Jump to content
Sturgeon's House

Leaderboard


Popular Content

Showing content with the highest reputation since 10/26/2014 in Posts

  1. 17 points
    Laviduce

    French flair

    For the mean time: Updated Special Armor Locations: Fuel Tank Locations: Main Gun Ammunition Locations: Crew Locations: Armament Locations: Powerpack Location:
  2. 17 points
    This is an article simply to show you guys here how Waffentrager is a faker. The original article ( https://www.weibo.com/ttarticle/p/show?id=2309404213101531682050) was written in Chinese and Japanese. For better understanding I will translate and edit the article and post it here. And I must tell you why I want to reveal this shit: Long time ago I found many sayings from Waffentrager’s blog which I had never heard of, so I turned to my Japanese friend and IJA tank researcher Mr.Taki and asked him to confirm a few of them. In the end it turned out that none of Waffentrager’s article is true. I once argued with him and he not only failed to give out his reference but also deleted my replies! I’m very angry! Now let’s get started. At the very beginning I recommend all of you who opened this post to take a look at Waffentrager’s original article, that will help you understand what I’m debating. Here is the link to the original article: https://sensha-manual.blogspot.jp/2017/09/the-ho-ri-tank-destroyer.html?m=0 In China we need to use VPN(aka “ladder-梯子” or “the scientific way of browsing the Internet-科学上网” in Chinese)to open that link above so at first I post out Waffentrager’s original post in the form of screenshots in my article. I’ll skip that here. Fig.1: I will skip his original article. Now, I had raised my first question here: Please take a look at the screenshot: Fig.2: My first question In the original article, Waffentrager insisted that the Type 5 gun tank was built in July, 1944 and fully assembled in August. It was also put into trials at the same time. Fig.3: Waffentrager’s original article. But, is that true? Let’s have a look at the Japanese archive: Important Fig.4: Archive code C14011075200, Item 4 Notice the part with the red, this is the research and develop plan for the Japanese Tech Research center in 1943, and had been edited in 1944. ◎砲100(Gun-100) is the project name for the 105mm gun used by Type 5 gun tank. The column under it says: “Research a tank gun with 105mm caliber and a muzzle velocity of 900m/s”. This means that the gun had just begun to be developed and from the bottom column we can know that it was PLANNED to be finished in 1945-3[完成豫定 means ”plan to be finished” and 昭20、3 means ”Shouwa 20-3”. Shouwa 20 is 1945 in Japan (you can wiki the way for Japanese to count years I’m not going to explain it here)] Next let’s move on to the Type 5 gun tank itself, here is the Japanese archive: Important Fig.5: Archive code C14011075200, Item 7 “新砲戦車(甲)ホリ車” is the very very first name of Type 5 gun tank, it should be translated into:”New gun tank(A), Ho-Ri vehicle”. “ホリ” is the secret name of it. Still from the column we can easily know that Ho-Ri was also planned to be finished in 1945-3. But under that column there is another one called:”摘要(Summary or outline)”, in this it says:”砲100、第一次試作完了昭和19、8”, In English it is: “Gun-100, First experimental construction(prototype construction) finished in Shouwa 19-8(1944-8)” What does it mean? It means that in 1944-8, Only the 105mm gun used by the Type 5 gun tank was finished! If the Ho-Ri tank itself was finished why it was not in the 摘要 column? So how could an unfinished tank mounted the prototype gun? Waffentrager is talking bullshit. Also from Mr.Kunimoto’s book, he gave the complete schedule of the 105mm gun, here it is: Important Fig.6: Kunimoto’s schedule “修正機能試験” means ”Mechanical correctional test”, it took place in 1944-8, this matches the original Japanese archive(though this chart was also made from original archives). At that time the gun had just finished, not the tank. Next is this paragraph from Waffentrager’s article: Fig.7: Weighing 35 tons From the archive above(important Fig.5) we can learn from the second large column”研究要項(Research items)” that Ho-Ri was only PLANNED to be 35 tons, and maximum armour thickness was PLANNED to be 120mm, not was. Waffentrager is lying, he used the PLANNED data as the BUILT data. I will post out the correct data below later to see what Ho-Ri is really like when its design was finished. Fig.8: 全備重量-約三五屯(Combat weight-app.35t), 装甲(最厚部)-約一二〇粍(Armour, thickest part-app.120mm) At this time, some of the people might inquire me that:”Maybe the Type 5 gun tanks were really finished! You just don’t know!” Well, I will use the archives and books to tell these guys that they are totally wrong. None of the Type 5 gun tank was finished. Always let’s look at Waffentrager’s article first. He said that a total of 5 Ho-Ri were completed. Fig.9: Waffentrager said 5 Ho-Ri were completed. He also put an original Japanese archive(C13120839500) to “enhance” his “facts”. Fig.10: Waffentrager’s archive Everyone can see the”ホリ車,1-3-1” in the document, and someone might actually believe that 5 Ho-Ri were actually built. But they are wrong! Waffentrager is cheating you with “only a part of the original document”! Here is what the original archive really looks like: Important Fig.11: Archive code C13120839500, Item 7 “整備計画” is “Maintenance plan” in English, again it was PLAN! The whole plan was made in 1944-12-26. I don’t actually know how Waffentrager can misunderstand this, maybe he doesn’t even know Japanese or Chinese! Important Fig.12: The cover of the same archive, “昭和十九年十二月二十六日” is 1944-12-26” in English. I have other archives to prove that Ho-Ri were not finished as well: Important Fig. 13 and 14: Mitsubishi’s tank production chart made by the American survey team after the war ends. From the chart you can only find out Type 4 and Type 5 medium tanks’ record. There is no existence of Type 5 gun tank Ho-Ri, or the”M-5 Gun Tank” in the chart’s way. Except for the archives, many books written by Japanese also mentioned that Type 5 gun tank were not finished: Fig.15: Kunimoto’s record. “二〇年五月完成予定の五両の終戦時の工程進捗度は、やっと五〇パーセントであり、完成車両出せずに終戦となった。” In English it’s: “When the war ended, the five Ho-Ri planned to be finished in 1945-5 had finally reached 50% completion. No completed vehicle were made when the war ended.” Here is another book written by Japanese with the help of former IJA tank designer, Tomio Hara: Important Fig.16: Tomio Hara’s book “完成をみるには至らなかった” Again he emphasized that the tank was not finished. Also when Ho-Ri’s design was finished its combat weight was raised to 40 tons, not the planned 35 tons. It was only powered by one “Modified BMW watercooled V12 gasoline engine”, rated 550hp/1500rpm. In Waffentrager’s article he said later a Kawasaki 1100hp engine were installed, but obviously that’s none sense. There was really existed a Kawasaki 1100hp engine but that is the two BMW V12 engine(Same engine on Type 5 gun tank or Type 5 medium tank) combined together for Japanese super-heavy tank O-I use. It will take much more room which Ho-Ri do not have. Fig.17: O-I’s engine compartment arrangement. There’s no such room in Ho-Ri for this engine set. And last here are the other questions I asked Fig.18: Other questions I asked I have already talked about the questions regarding C13120839500 and the engine. As for the gun with 1005m/s muzzle velocity, the Japanese never planned to make the 105mm gun achieve such a high velocity because they don’t have the enough tech back then. Also from the archive C14011075200(important fig.4) the 105mm gun was designed only to reach about 900m/s. So, after all these, how did Waffentrager replied? I will post out the replies from my E-mail(because he deleted my replies on his blog). Fig.19: Waffentrager’s first reply He kept saying that my archive is not the same as his and he is using his own documents. I didn’t believe in these shit and I replied: Fig.20: My reply Last sentence, the Ho-Ri III he was talking about is fake. There are only Ho-Ri I(The one resembles the Ferdinand tank destroyer) and Ho-Ri II(The another one resembles the Jagdtiger tank destroyer). He even photoshoped a picture: Fig.21: Waffentrager’s fake Ho-Ri III Fig.22: The real Ho-Ri I and the base picture of Waffentrager’s photoshoped Ho-Ri III in Tomio Hara’s book. Many same details can be seen in Waffentrager's fake Ho-Ri III The 4 variants of up-armoured Type 3 Chi-Nu medium tank is also fake, I will post his original article and the confirmed facts I got from Mr.Taki by E-mail. Fig.23: 4 models of up-armoured Chi-Nu by Waffentrager Fig.24: Mr.Taki’s reply Waffentrager used every excuses he could get to refuse giving out the references, and finally he deleted my comments. What an asshole! Fig.25: Our last “conversation” Fig.26 He deleted my comment. So, as you can see, Waffentrager is really a dick. He is cheating everybody because he think that we can’t read Japanese. Anyway I still hope he could release his reference and documents to prove me wrong. After all, I’m not here to scold or argue with somebody, but to learn new things. Also if you guys have any questions about WWII(IJA) Japanese tanks, feel free to ask me, I’m happy to help.
  3. 14 points
    You've seen them before; poorly edited videos with an alternating loop of John Phillips Sousa and Weird Al, purporting to tell you about the various design mistakes armored fighting vehicle designers have made over the years: But does the maker of these videos one Blacktail Defense, know shit about AFV design himself? Haha, no, no he does not. Because of Sturgeon's House strict hate-speech enforcement laws, I am compelled to mention that Blacktail Defense is a furry. So know that should you click any of the links to his material, you will need to decontaminate yourself per protocol DG-12-23A with bleach. Blacktail Defense is a military reformer, a storied and interesting political movement in the United States that has gone from being a force of some consequence to being a ragtag group of scoundrels. I'm not going to say that they weren't idiots and scoundrels when they were of consequence, n.b. Military reformers are at they're strongest when they're on the attack. They're a lot like creationists that way; when they can hurl invective at (mostly imaginary) weaknesses within whatever it is they hate, they can look like concerned citizens campaigning for the taxpayer's right to have their money spent wisely and the soldier's right to have the best practical equipment. But give a military reformer some lined paper and a slide rule and tell them to come up with a design, rather than tear down an existing one, and you will quickly see that these people have no idea what they're talking about. Ready? This is taken directly from Blacktail's furaffinity page. Careful analysis shows that, no, this man has no idea what the everliving fuck he's talking about. Are you ready? No, you're not, but let's go ahead anyway. "The Tigerwolf may look vaguely similar to contemporary MBTs, such as the ubiquitous M1-series Abrams, but is in fact wrapped around a lot of design features and technology that are comlpetely alien to today's tanks." Blacktail is going to prove to you that he's a better tank designer than all those idiots at Chrysler by designing a tank using technologies that didn't exist at the time of the design of the Abrams. "For starters the crew is quite large, with a Commander, Driver, Gunner, TWO loaders, and an Engineer. Many designers favor a smaller crew, usually adding an autoloader to eliminate the Loader from the crew (like in the Russian T-64 through 90, the French Leclerc, and the Chinese Type 85 through 99)." ... What? "However, there are a lot of problems with a smaller crew. First, autoloaders work at a painfully slow pace (14 seconds to reload in a T-72), which gives manual-loading tanks a huge rate-of-fire advantage (just 4 seconds in the M1A1 Abrams)." "There's no autoloader either, as that only slows the ROF, requires smaller, less powerful and versitile ammo to be used, adds another complex, delicate set of moving parts to break, and only serves to expand the guantlet of things that can hurt you inside the vehicle.In fact, the Tigerwolf's main gun ammo is extremely large and heavy, and probably would break an autoloader --- it's would be an incredible feat of strength for a single Loader crewman to load in under 10 seconds." The Leclerc uses the same ammunition as the Abrams and Leopard 2. As for his 145mm smoothbore howitzer ammunition breaking an autoloader, does he not know that the Pz 2000 SPG has an autoloader for its 155mm gun? Of course he doesn't know that; Blacktail doesn't know what he's talking about. "The engineer is useful as well, because the large size of the Tigerwolf --- coupled with it's simple drivetrain (most modern tracked vehicles have a deceptively simple drivetrain) and small, flat engine (compred to a "Vee" or gas turbine) make for easy engine maintnance[sic] and repairs from inside the tank --- there's no need to abandon it if you lose a sparkplug while under small arms fire." Simple drivetrains, eh? Note that per the graphic, the Tigerwolf has a diesel wankel. Does Blacktail not know that diesel engines don't have spark plugs? Of course he doesn't know that; Blacktail doesn't know what he's talking about. (Diesel wankels don't exist. Three companies have tried making them; Rolls Royce, John Deere and some Japanese company I CBA to look up. None of the three ever got them to mass production. I'm not sure what the problem was.) "As for the armor, instead of using a large amount of steel and other metals, most of the Tigerwolf's armor is made up of thick panels and blocks of woven fabric Carbon 60 and 70 --- which are genarically[sic] known as "Fullerine". [sic] Fullerine has ove 100 times the tensile strength of steel, it's 10's of times lighter, and theoretically could be manufactured quickly and inexpensively. Essentially, the Tigerwolf has a sort of "Super Kevlar" armor, but unlike current Kevlars (which are made of polimers[sic] or composites), fullerine does not have a molecular structure that distorts or melts under heat or pressure --- a single piece of this new type of armor can withstand MANY direct hits from rounds with tank-killing power, KE and CE alike." Ah yes, fullerenes; every hack futurist's favorite crutch. Fullerenes have many interesting and useful properties, but their large-scale bulk mechanical properties may not be that amazing. Many materials have amazing strength at small scales, but disappointing strength at macro scales. Sapphire whiskers are an example. Moreover, high tensile strength (which is what fullerenes have going for them), does not necessarily imply that a material will make good armor. The properties that make materials effective against high-velocity threats are somewhat esoteric. Aluminum alloys, for instance, have a better strength to weight ratio than does steel, and while several of them do protect better on a weight basis than steel against lower velocity threats like artillery fragments and small arms fire, suffer badly against high-velocity penetrators and HEAT threats due to sheer failure modes that only exist at those higher velocity ranges. Also, why the fuck does Blacktail think that "Kevlars" melt under pressure? Aramids don't melt. "Even though it's much larger than an M1A1 Abrams, the Mk.75 Tigerwolf is over 30% lighter, and can swim over water obstacles, rather than slog though on the bottom. And because it floats, there are no depths that it cannot cross." This is how big a 40 tonne boat is. "Also important is it's low ground pressure, stemming from it's low 40-ton weight, super-wide tracks, low height, and enourmous horizontal size --- it has the ground pessure of a "Light Track" vehicle, like the M113 Gavin. This is important because almost half the world's surface is closed to heavy tracks (again, the M1A1 Abrams), due to thier height, ground pressure, and high centers of gravity. The Tigerwolf can directly cut across many areas that no existing or projected MBT will ever be able to --- not to mention traverse certain terrain features, such as bridges and paved roads, without damaging them." Is Blacktail under the impression that it's ground pressure that damages bridges? Jesus, if that were true the last thing you'd want to get anywhere near a bridge is a car. "As the Tigerwolf has 40% more power and torque than the M1, and weighs 30% less, it is 40% faster and could probably accelerate as quickly as a Humvee. This would make contemporary tanks very hard-pressed to cut-off a Tigerwolf, and no current or projected tanks could ever hope to pursue a Tigerwolf. Other advantages offered by the powerpack include a small number of moving parts, extremely low vibration and ocillation (inherent to Wankel Rotaries; not in piston engines), low heat emissions (less than in 700+ degree piston engines, or 1500+ degrees in Gas Turbines), a very small, flat, light engine block, and stonger individual components than in any current or projected tank engine, and a 5-speed AT, to take advantage of the high engine output. " Uh huh... So this is a magical wank(el) engine that has equal SFC to a diesel, rather than falling between a diesel and a turbine as existing ones do. "Other advantages offered by the powerpack include a small number of moving parts, extremely low vibration and ocillation (inherent to Wankel Rotaries; not in piston engines), low heat emissions (less than in 700+ degree piston engines, or 1500+ degrees in Gas Turbines), a very small, flat, light engine block, and stonger individual components than in any current or projected tank engine, and a 5-speed AT, to take advantage of the high engine output." WHAT THE FUCK KIND OF TURBINE REJECTS HEAT AT 1,500 DEGREES?! The highest turbine inlet temperature on record is 1,600C! Per Honeywell, AGT-1500's exhaust temperature is 500 C, but it's unclear if that is before or after it enters the recuperator. And if he's using bullshit Imperial units he's still wrong. If you don't know the difference between heat rejection temperature and turbine inlet temperature, you have no business discussing turbines. "All tanks require high firepower, and the Mk.75 Tigerwolf has plenty of it. The large size of the Tigerwolf's hull and turret enables a heavier-caliber howitzer to be used than on any tank currently in service --- a 145mm Smooth-Bore Howitzer. Because the German-designed M256 120mm smoothbore (M1A1, M1A2, Leopard 2, etc.) has a 40% larger punch than the British-designed M67 105mm Rifled-bore (the standard to which ALL other tank guns are judged --- used on too many tanks to list), the Tigerwolf's gun probaly has at least 20% more punch than the M256 --- enough to outrange any of today's tank guns, with enough penetration to destroy an M1A1 from well beyond it's maximum gun range." Any fictional Main Battle Wank needs to have a smitey, terrifying weapon... I'm not sure why Blacktail has saddled his design with a howitzer. Also, how many places on Earth are there where you can even see further than the engagement range of an M1's armament? "The Co-Axial MachineGun (COAX) fires 7x50mm rifle rounds, which combine the low cost and recoil of the 5.56x45mm NATO round, with the accuracy and penetration of the 7.62x51mm NATO round. 7mm rounds would also have a smaller casing daimeter than a 7.62mm round, which when coupled with significantly larger magazines and canisters, means the Tigerwolf totes one hell of a lot of MG ammo. As such, it is unlikely that a Tigerwolf will have to resupply MG ammo during a battle, and may even have thousands of rounds to spare --- if it is supporting friendly troops, the Tigerwolf may be able to spare a few thousand rounds for them." Someone doesn't know the difference between case head diameter and caliber. "A smooth ride and steady aim are achieved through hydropneumatic suspension and stabilization (versus the comparatively rougher torsion and hydraulics used in current and projected tanks) . The gun, turret, and hull each have thier own stabilization. While each of these are mechanically independant, they are balanced and co-ordinated via computer (which also feeds stability data to the gunnery computer, adjusting the GPS crosshairs in real time). This is unlike current tanks, whose ballistics comuters only react indirectly to the actual stability of the vehicle." I don't know what any of this means, except that Blacktail doesn't know how suspension and stabilization work. That's all I can stand. I'm done. Go read it if you want to, or not, whatever.
  4. 14 points
    My Dad was in the Navy from 1965 to 1969. He's been dead since 2000, so there is no asking him for info on this stuff, my mom is around but won't knot much about the Navy details so I am putting this together from memory and whats in the photos. The slides were not in great shape, and the first set of scans were rough, and then the scanner broke. So, since Amazon didn't have the same model anymore, I spent a little more money and got a much nice scanner, with a better "technology" for film scanning, and it fixes the flaws when it scans them. The results are remarkable. As far as I know these images were taken with a Minolta 35mm Camera, I guess an SLR, since he had a bunch of lenses for it. I learned photography with it, and have a few pictures of my GTO I took with his Camera. This was the type of camera you focuses, and set the light settings, and had to hand wind. Considering how much harder a camera was to work back then, I think my old man was a reasonably talented photographer. As far as I can remember he went to boot camp in San Diego, then he went to schools for Ejection Seat Maintenance and Air Condition systems on the F4J Phantom. He got assigned to VF-33, part of CAG-6, with VF-102, VA-82, VA-86, VA-85, RVAH-13, VAW-122, VAW-13 Det. 66, and VAH-10 Det. 66. CAG-6 was assigned to the USS America, who was about three years old and about to go on a world cruise, that would include the Ships only Vietnam deployment in 1968. When the ship got back, it was stationed on the east coast, and VF-33 went to CAG-7, and ended up on the Independence. My dad was with them for at least one work up cruise, since there are a set of photos from that ship. By mid 69 he was back in San Diego, working with VF-121, the west coast RAG, waiting to get out . I do not have any photos yet from San Diego, at least Navy stuff. Here is a shot of the CVA-66 USS America, she displaced 61,174 tons empty, 83,500 full load. She was the second Kitty Hawk Class Carrier, she would spend the majority of her Career in the Med. (if the logo for the Sherman Tank Site seems like its in odd places, its usually covering a flaw the scanner could not fix) Here's a VF-33 Phantom. A VF-102 Phantom, an F-4J the same as VF-33. Here are some pretty cool shots from an underway replenishment. It could be anywhere on the World cruise in 68. I think this is also from an Unrep, maybe the same one. This photo is one of my favorite, you get an A-7 and Sea Night for the the price of one! Old shot with bad scanner as a place holder for a duplicate. This shot is of the flight deck, by the cats on the angle deck looking forward. Not the kill mark on the intake of the F-4J, 212 sitting there, pretty cool. These last three shots are all from the USS Independence, in early 69, I assume off the East Coast on work ups for their upcoming Med Cruise. This is my old Man, Rick T, I'm pretty sure that's a Martin Baker Ejection seat right next to him. Several VF-33 Phantoms got shot down, and the seats always worked, so he had that going for him. This image was scanned on the original scanner, note how cruddy it looks, when get to this slide again, I'll post the improved version. Compare the below image to the one above too. I'll posts more as I water mark them and host them. There was a crossing of the line ceremony, that my Dad took a ton of pics on, its pretty interesting. It was really nice to find these, I had thought hey got lost in a move.
  5. 14 points
    (M4A3E8, ultimate production Sherman) This is a work in progress, please feel free to comment, or help me with info and links. Click here to see the new The Sherman Tank Website! All content is still discussed and previewed in this thread. If you have feedback or want to help with the content, this thread is the best place to do it. The Epic M4 Sherman Tank Information Post. SHERMAN: M4: M4A1: M4A2: M4A3: M4A4: M4A6: M50: M51 The Sherman tank over the last several decades has had its reputation severely soiled by several documentaries, TV shows, and books, all hailing it as a death trap, engineering disaster, or just a bad tank. The Sherman tank may be the most important, and arguably the best tank of the war. The only other contender for the best tank award would be the Soviet T-34. These two tanks are very comparable and would fight each other in later wars, staying very comparable through their service lives. This post will cover why the Sherman was a better tank than anything Germany, Italy or Japan produced during the war, on both a tactical and strategic level. I will not be reproducing the work of others, and will link to the places that already cover some information. I will cover all the major changes made to the each Sherman model. I will try and cover the many post war variants as well, but that could take months, there are a lot of variants of this venerable tank, including ones that involve putting the engine from one hull type into another hull type and or tanks modified by other countries with no feedback from the American designers. I’ll try and get civilian use in here as well. Some variants have heavily modified turrets, or replaced it with a new one. Basic Sherman History: The Big Stuff To really know why the Sherman was designed the way it was, you have to know about the M3 Lee. The M3 was the predecessor of the M4. It was based on M2 medium, the US Army’s only foray into modern medium tank design, and was the fastest way a tank could be designed with a 75 mm M3 canon fitted. The US lacked the jigs to make a turret ring big enough to house a gun that large in a turret; the Lee went into production while the turret ring problem was being solved, by mounting the gun in a sponson mount. It had become clear to the US Army that the 75mm canon would be needed based on feedback from the British, and observations of how the war was developing in Europe. One of the reasons for the reliability of the M4 design was the use of parts that started their design evolution in the M2 medium and were improved through the M3 production run. Over the life of M3 Lee and M4 Sherman the designs were continually improved as well, so a final production, M3, or M4A1, bared little resemblance to an initial production M3 or M4A1, yet many parts would still interchange. This is one of the reasons the Israelis had so much success updating the Sherman to the M50 and M51, these tanks used early small hatch hulls, that never had HVSS suspension installed, but the hulls took the updated suspension with few problems. When the Lee went into production, though it was far from an ideal design, it still outclassed the German and Italian armor it would face, and its dual purpose 75mm gun would allow it to engage AT guns with much more success than most British tanks it replaced. It was reliable, and well-liked by its users. When the British got enough Shermans, the Lees and Grants were sent to the Far East and saw use until the end of the war fighting the Japanese. The Lee excelled at infantry support, since it had a 37mm canon that could fire canister rounds, along with the 75mm gun and a lot of machine guns. Many of these Lee tanks ended up in Australia after the war. Lee variants: The Combat RV (early M3 Lee) M3 Lee: This was the first version of the tank and used a riveted hull with the R975 radial engine powering it, the suspension and tracks were very similar to the M2 medium. Early production tanks had an M2 75mm instead of the improved M3 gun. These tanks had a counter weight mounted on the shorter barrel. All Lees had a turret with 37mm M5 gun. The early production version had two hull mounted, fixed .30 caliber machine guns, another mounted coaxially with the 37mm gun, and another in a small turret, mounted on top of the 37mm turret for the commander. They built nearly 5000 of these tanks. The M3 was improved on the production line with things like removal off hull machine guns, and hull side doors. The mini turret mounted M1919A4 was not a popular feature, and was hard to use, but it remained on all Lees, and were only deleted from the Grant version produced exclusively for the British. If this version had a major flaw, it would be the riveted armor plates could shed rivets on the inside of the tank and these rivets bounced around like a bullet. This was bad for the crew, but, rarely resulted in a knocked out tank. A field fix for this was welding the rivets in place on the interior of the tank. Most of the M3 Lees produced went to the British. (cast hull M3A1) M3A1 Lee: This version of the Lee had a cast hull, and R975 radial power. It was really the same as the base Lee in most respects including improvements. 300 built. These cast hull tanks have a very odd and distinctive look. They look almost like a M3 Lee was melted. This hull casting was huge and more complicated than the M4A1 casting. Most of these tanks were used in the United States for training. M3A2 Lee: This Lee had a welded hull and the R975 powering it. 12 built. This version was more of a ‘proof of concept’ on welding a hull than anything. M3A3 Lee: Another welded hull but this one powered by the GM 6046 Twin Diesel. 322 built, like the base Lee, with the same improvements. This is the first vehicle the 6046 was used in, and most of the bugs were worked out on this model. M3A4 Lee: This version had a riveted hull and was powered by the A-57 multibank motor. This motor was so large the hull had to be stretched for it to fit; it also required a bulge in the top and bottom of the hull to fit the cooling fan. They also had to beef up the suspension, and the suspension units designed for this would become standard units on the Sherman. This would be the only version of the Lee with the improved bolt on offset return roller VVSS, otherwise this tank was very much like the base M3. 109 built. This motor’s bugs were worked out on this tank and would go on to power a large chunk of Sherman production. (Monty's M3A5) M3A5 Grant: Another welded hull, powered by the GM 6046 Twin diesel with a new bigger turret to house British radios. 591 built. This new turret deleted the small machine gun turret on the roof of the 37mm turret. This version was used only by the British. The famous General Montgomery’s personal M3A5 is on display in England, at the Imperial War Museum in London. . . . The majority of Lee and all Grants saw service with the British, and many Lees went to the Soviet Union. They were generally well liked by both nations and more reliable than most of its British and German contemporaries. These tanks were better than the enemy tanks they faced until the Germans up gunned the Panzer IV series. When they were replaced with M4s of various types the M3 were shipped to the Far East for use in Burma and New Guinea. The Japanese had no tank that could take on a Lee, let alone a Sherman. Using soldiers as suicide bombers, and mines still worked though, there was also a pesky 47mm AT gun, but it was rare. They saw limited use in the US Army’s hands some seeing combat in North Africa, because US combat units lost their Shermans to replace British losses, and a few were used in the PTO. The Sherman owes it success to the lessons learned producing the Lee and from its use in combat. The 75mm gun and automotive systems, even the more complicated ones, would be perfected in the Lee and re-used in M4, and the Sherman only had one motor not tested in the Lee first. Many of the Lee variants were produced at the same time and the numbering system was more to distinguish between hull and engine types, not to model progression like in aircraft, and other tanks. This practice was carried over to the M4 series as were all the engines used in the Lee. Many people familiar with the way the United States designated aircraft during the war figure it was carried over to tanks and think an M3A1 was an improved M3, and an M3A2 was an improved A1. This is not the case, as many of these versions were produced at the same time, and they all received the same sets of improvements, though some factories took longer to implement things than others. The M4 went into production as soon as the jigs for the turret ring were produced and ready to be used. Production actually started on the cast hull M4A1 first, with the welded M4 following right behind it. Like the Lee, there were many version of the Sherman in production at the same time. There are many photos of Lee’s coming off the production line, with Shermans in the line right behind the last Lee, so there was no real gap in production between the two tanks at most of the factories. The Sherman variants: The Design Matures First off, Americans referred to the Sherman as the M4, or M4 Medium, or Medium, the Sherman name was not commonly used until post WWII. The British came up with the name for the M4 and referred to it with their own designation system that will be covered in more detail later. They also named the Lee, and Stuart, and at some point the US Army just stuck with the naming scheme. The full story behind this is still a minor mystery, with US war time documents confirming the ‘general’ names were at least used on paper by the US Army during the war. Now let’s cover the factory production versions of the Sherman. Also keep in mind, it is very hard to define just how a Sherman may be configured without really knowing where and when it was produced. In some rare cases, large hull, 75mm armed Shermans got produced with normal ammo racks, when the norm for large hatch hull tanks was wet ammo racks. . . . (this is a very early production M4 with DV ports that are not welded closed and have not had armor added over them) M4 Sherman: These tanks used the same R975 motor as the M3, and M3A1. The vast majority of the bugs in this automotive system were worked out before the M4 even started production. This really helped give the Sherman its reputation for reliability and ease of repair. The M4 had a welded hull with a cast turret mounting the M3, 75mm gun. Early variants had three hull machine guns, and two turret mounted machine guns. The hull guns were all M1919A4 .30 caliber machine guns, two fixed, and one mounted in a ball mount for the co-drivers use. The fixed guns were deleted from production very rapidly. The turret armament remained unchanged for the whole production run: Using the M3 75mm gun with the M1919A4 coaxial machine gun and M2 .50 caliber mounted on the roof. The turret would be the same turret used on all early Shermans and would be interchangeable on all production Shermans. This version was not produced with the later improved T23 turret but did get some large hatch hulls in special variants. There were two variants of the M4 to be built with the large hatch hull. The first, the M4(105) was a large hatch hull mated to the 105mm howitzer, on the M52 mount, in the standard 75mm turret. These hulls did not have wet ammo racks or gyro stabilizers, and the 105mm turrets had an extra armored ventilator, the only turrets to have them. The M4 (105) gun tanks had a special mantlet, with four large screws in the face, unique to 105 tanks. Production started in February of 44, and continued well into 45, with late production M4(105) tanks getting HVSS suspension. These tanks were used as replacements for the M7 Priest in tank units, and spent most of their time being used as indirect fire support, like the M7 they replaced. One other variant of the M4 to get the large hatch hull(100 or so small hatch casting were made as well), this was the M4 ‘hybrid’, this hull was welded, but used a large casting very similar to the front of the M4A1 on the front of the hull. It was found that most of the welding hours building the welded hull tanks were spent on the glacis plate. They figured by using one large casting, incorporating the hatches and bow gun would save on welding time and labor costs. (This is an M4 hybrid, large hatch tank. but with no wet ammo racks) These M4 hybrids were used by the British to make Ic Fireflies. They liked the 75mm turret these tanks came with since they already had a loaders hatch, this saved them time on the conversion since they didn’t have to cut one. These large hatch M4s did not get the improved T23 turret, but did have wet ammo racks and all the large hatch hull improvements. Most of these tanks were shipped to Europe or the Pacific, making survivors rare. The M4 along with the M4A1 were the preferred US Army version of the Sherman until the introduction of the M4A3. This tanks was made in five factories from July of 42 to March of 45, 7584 produced. (this image is a small hatch M4A1 with DV ports welded closed and add on armor over them, not the very early turret with small mantlet. The suspension on this tank was probably updated from the early built in roller type during a depot rebuilt. Image from the awesome sherman minutia site) M4A1 Sherman: This was virtually the same tank as the M4, with the same motor and automotive systems and armament. The key difference was the cast upper hull. This huge upper hull casting was one piece. This was a very hard thing to do with casting technology at the time, and something the Germans could not have reproduced, they lacked the advanced technology, and facilities needed to do so. Everything from hatches to wheels, and turrets, and guns were interchangeable with the M4 and other Sherman models. This version saw production longer than any other hull type. It also saw all the upgrades like the improved large hatch hull with wet ammo racks, the T23 turret with 76mm gun, and HVSS suspension system. It was 30 of these M4A1 76 HVSS tanks that were the last Shermans ever produced. The M4A1 was also the first to see combat use with the improved M1 gun and T23 turret during operation Cobra. Three factories produced 9527 M4A1s with all turret types from Feb 42 to July of 45. The US Marines used one Battalion of these tanks on the Cape Gloucester campaign, small hatch M4A1 75 tanks. This was the only use of this tank by the Marines. (M4A2 75 mid production with improved drivers hoods, from this angle you can not tell the difference between an M4 M4A2, M4A3, image courtesy of the sherman Miniutia site) M4A2 Sherman: This version of the Sherman used a welded hull nearly identical to the M4, but with a pair of vented armored grates on the rear hull deck. The M4A2 tanks used the GM 6046 twin diesel. This version was produced with all the improvements the other types got, like the large hatch hull with wet ammo racks, the T23 turret with improved M1 gun, and HVSS suspension. This version would see very limited combat in US hands, most being shipped to Russia with a few early hulls going to the Brits and USMC. This was the preferred version for Soviet lend lease deliveries, since the USSR was using all diesel tanks. It was produced in six factories with 10,968 of all turret types produced from April of 42 to July 45. A little trivia about this version, the Sherman used in the movie Fury, was actually a late production M4A2 76 HVSS tank. The only way you can tell a late A2 from a late A3 is by the size of the armored grills on the back deck. They did a great job of hiding this area in the movie. The Marines operated a lot of small hatch and a fairly large number of large hatch M4A2 tanks, until the supply of 75mm armed version dried up in late 1944. Then they switched over to large hatch M4A3 75w tanks, but there were some A2 holdouts amongst the six battalions. (this is an M4A3 large hatch 75mm tank, it has wet ammo racks and a hatch for the loader.) M4A3 Sherman: This would be the base for what would be the final Sherman in US Army use, seeing action all the way out to the Korean War in US Army hands. This tank had a welded hull just like the M4, A2, and A4, but used a new motor. The Ford GAA V8, this motor took some time for its bugs to be worked out, so unlike say, the Nazi Germans, the US Army didn’t use it until it was ready for serious production. When it was, it became the preferred US Army version of the tank in both the 75mm and 76mm armed tanks. It would see all the improvements, and be the first hull type to take the HVSS suspension system into combat for the US Army. The M4A3E8 or M4A3 tank with T23 turret and HVSS suspension bolted on would be the final and ultimate US Army Sherman. It would be produced in three factories with all turret types, 12,596 built in total between June 42 and June of 45. After WWII when the Army wanted to standardize on one Sherman type, any M4A3 large hatch hull they could find would have a T23 turret and HVSS suspension installed on it. The Army was so thorough in these conversions no M4A3 large hatch 75mm gun tanks are known to have survived with the original turrets installed. Any M4A1 HVSS 76 and M4A2 HVSS 76 tanks in Army inventory would have been robbed of their suspensions and turrets so they could be installed on M4A3 large hatch hulls. (an M4A3E2 Jumbo with correct M3 75mm gun) The M4A3E2 Jumbo, Fishers fat and special baby! FTA was the sole producer of one very special variant of the Sherman, the M4A3E2 Jumbo. This version of the Sherman was the assault Sherman, though not expressly designed for it, was manufactured to be able to lead a column up a road and take a few hits from German AT guns or tanks so they could be spotted without having to sacrifice the tank. It had a lot of extra armor, and could take a lot of hits before being knocked out, but was still not impervious to German AT gun fire. Only 254 of these tanks were produced, and all but four were shipped to Europe for use by the US Army. They were all armed with the M3 75mm gun. There was a surplus of M1A1 76mm guns in Europe due to an aborted program re arm 75mm Sherman tanks with the guns. Many of the Jumbo’s ended up with these guns, but none were ever factory installed. The tank was no different in automotive components from the M4A3 tanks, with the sole difference being the slightly lower final drive gear ratio, going from a 2.84:1 ratio in the base Shermans, to 3.36:1 on the Jumbos. This reduced the top speed slightly but helped the tank get all the extra armor moving. The Jumbos were well liked by their crews and in great demand; no more were built though, the only batch being produced from May to July of 1944. Had the invasion of Japan been needed, a special Jumbo with larger turret that included a flame thrower was considered, but we all know how that story ended. This version of the Sherman was issued to the Marines when the M4A2 75mm tanks went out of production. The version they would have been issued, would all have been large hatch M4A3 75w tanks, and they may have gotten some with HVSS. (this is an M4A4, the best way to tell is the extra space between the road wheels) M4A4 Sherman: This tank is the oddball of Sherman tanks. It had a welded hull and used the A-57 multibank motor. A tank motor made from combining five car motors on one crank case. As complicated as this sounds, it was produced in large numbers and was reliable enough to see combat use, though not in American hands in most cases. In US use they tried to limit it to stateside training duty. The Brits found it more reliable than their native power plants, and liked it just fine. This version never got the improved large hatch hull or T23 turret with M1 gun. Most were shipped to the Brits via lend lease and many were turned into Vc Fireflies, making it the most common Firefly type. The Free French also got at least 270 of these tanks in 1944. The Chinese also received these tanks through lend lease but not many. The US Marines operating these tanks in the states as training tanks, 22 of them for two months before they were replaced by M4A2s. This tank had a longer hull, like its Lee cousin to accommodate the big A-57 motor. It was the first Sherman version to go out of production. It was produced in one factory (CDA) from July of 42, to November of 43 with 7499 built. The A4 has the honor of being the heaviest and largest standard Sherman. The larger hull to accommodate the A57 motor, and the motor itself added weight. The British used these tanks extensively in combat. These tanks show up in British test reports as well, often pitted against tanks like the Cromwell in reliability or other tests, and usually coming out ahead. Anyone who has ever changed the spark plugs on their car should really be able to appreciate how hard a motor made by tying five six cylinder automobile engines together, on one crank would be. . . . All Sherman variants share a lot of details and most spare parts interchange. Only the motors really call for different parts. All early Sherman tanks had 51mm of armor at 56 degrees on the front hull, and 76mm on the front of the turret. The 56 degree hulls are called small hatch hulls because the driver and co-driver had small hatches that forced them to twist sideways to get in and out. They also started out with direct vision ports along with periscopes for crew vision. Even the cast tanks matched these specs and the hatches from a cast tank could be used on a welded tank. These early hulls had some of the ammo racks in the sponsons above the tracks. Not a great place for ammo, but not an uncommon one for it either. As they improved the hull, they added plates over the direct vision ports and eventually removed them from the castings. Large plates were eventually welded over the ammo racks on the sides, and this extra armor was eventually just added into the casting on the cast hulls. It’s safe to say no small hatch tanks were factory produced with a 76mm gun or improved T23 turret. The major hull change came when they upgraded the drivers and co drives hatches making them bigger. They also thickened the front armor to 64mm but reduced the slope to 47 degrees to fit the new driver’s hatches. The M4 (hybrid and 105 only), M4A1, A2, and A3 were produced with these improved large hatch hulls. Many of these improved large hull tanks had the original 75mm gun and turret. Even the M4A3 with HVSS suspension was produced with the 75mm gun and turret. Most of the large hatch production was with the new and improved T23 turret. These larger hatch hulls would still accept the majority of the spares the older hulls used and the lower hull remained largely unchanged and would accept all the suspension types. Any large hatch M4A3 hull was likely converted to an M4A3 76 HVSS post WWII. Through the whole production run minor details were changed. The suspension saw many different version before the final HVSS type was produced. The track types also changed and there were many variants made from rubber and steel, or steel. There were even at least six different types of road wheel! There are so many minor detail changes, the scope is to big to cover in this post, needless to say, the only other tank I know of with so many minor changes over the production run was the Tiger, and in the Tigers case it’s just sad, with so few produced, it means almost no two tigers were the same. This was not the case for the Shermans and the changes did not slow production down at all and in many cases were just different because a particular part, like an antenna mount, or driver’s hood, could have been sourced from a different sub-contractor, and the parts may look different, but would function exactly the same. Tiger parts are not good at interchanging without modification, and a crew a craftsmen to custom fit them. The changes made to the Sherman were either to incorporate better parts, or to use a locally made substitute part for one in short supply, so making their own version allowed them to continue production without a slowdown. To really get a handle on these differences there are two really great sources. This is the easy, way: Sherman Minutia site a great site that really covers the minor detail changes on the Sherman tank very well. You can spend hours reading it and looking over the pictures. It explains little of the combat history of the Sherman but covers the minor changes on the vehicles themselves very well. You can spend hours on this site learning about minor Sherman details. It is also a primary source for this post. Another great way is to get a copy of: Son of a Sherman volume one, The Sherman design and Development by Patrick Stansell and Kurt Laughlin. This book is a must have for the Sherman plastic modeler or true enthusiast. It is filled with the tiny detail changes that took place on the Sherman production lines from start to finish. They cover everything from lifting eyes to ventilators, casting numbers, to most minor change to the turrets. Get it now before it goes out of print and the price skyrockets. I liked it so much I bought two! The turret saw continual change as well, but remained basically the same. The 75mm gun never changed but its mount and sighting system did. The turret lost the pistol port, and then gained it back. It gained a rotor shield over time and an extra hatch. All these detail changes are covered on the site above and in the Son of a Sherman book. The important thing to note was the tank saw continual improvement to an already reliable, and easy to produce design. The Sherman was easy to produce for an industrial nation like the USA, but beyond Nazi Germany’s technical capabilities for several reasons, like large casting and the gun stabilization system, or even multiple reliable motors to power the tens of thousands of tanks made. In the basics section I’m only going to cover one more thing. The Sherman tank was not as blind as the tanks it faced. The M4 series, from the first production tank, to the final Sherman that rolled off any of the production lines, were covered in periscopes or view ports for the crew. The gunner had a wide angle periscope that had incorporated the site for the main gun, and they very quickly added a telescopic site to go with it. The commander had a large rotating periscope in his rotating copula. The loader had a rotating periscope and the driver and co-driver had two, one in their hatch, and another mounted in the hull right in front of them once the DV ports were deleted (non-rotating). Later version added a direct vision cupola and a periscope for the loader in his new hatch. All these periscopes could be lowered and the port closed, and if damage easily and quickly replaced from inside the tank. All this gave the Sherman an advantage in spotting things outside the tank; they were still blind, just not as blind as most of the tanks they would face. Finding an AT gun in a bush could be very challenging for any tank, and infantry if not scared off by the presence of a tank in the first place can sneak up on one pretty easy. This was a big advantage when it saw combat and throughout the tanks career it was always one of the best if not the best tank of the war. It was reliable, the crew had a good chance of spotting enemies before other tank crews, the gun was stabilized, fast firing, and accurate. It was as good or better than most of the tanks it faced, even the larger German tanks. These tanks were largely failures, with only long debunked Nazi propaganda propping up their war record. The Sherman has the opposite problem. Sherman Builders: Just How Many Tank Factories Did the US Have Anyway? They Had 10 and 1 in Canada. Most of the information in this section will be a summation of the section in Son of a Sherman. Other stuff I had to dig around on the internet for. Anyone who has more info on the tank makers, please feel free to contact me. Parts from all these tank makers would interchange. Many used the same subcontractors. I don’t think anyone has tried or if it’s even possible to track down all the sub-contractors who contributed parts to the Sherman at this point. Some of the manufactures were more successful than others, some only producing a fraction of the total Sherman production, others producing large percentages. By the end of production, all the US and her allies needs for Shermans were being handled by just three of these factories. American Locomotive (ALCO) ALCO also produced M3 and M3A1 Lees, and made Shermans up to 1943. They were a fairly successful pre-war locomotive manufacturer founded in 1901 in Schenectady, New York. They also owned Montreal Locomotive works. ALCO made several version of the Sherman, and stayed in the tank game until the late 50s, helping with M47 and M48 production. The company went under in 1969. Baldwin Locomotive Works (BLM) Baldwin was another early producer, building three versions of the Lee, The M3A2, M3A3, and M3A5. They mostly built small hatch M4s, with just a handful of M4A2(12). They were out of the Sherman game by 1944 and out of business by 72. They were founded in Philly in 1825, and produced 70,000 steam locomotives before it died. (M4A4 and M3s being built side by side at CDA, photo courtesy of the Sherman Minutia site ) Chrysler Defense Arsenal (CDA) Chrysler Defense Arsenal is kind of special. It was a purpose built tank factory, funded by the US Government, and managed and built by Chrysler. Construction on the factory started in September of 1940. Completed M3 Lee tanks were rolling of the line by April of 1941. This was before the factory was even finished being built. It was built to stand up to aerial bombing. They produced M4A4, and M4 tanks as well and M4 105s, M4A3(105)s, and M4A3 76 tank and nearly 18,000 of them. Chrysler was the sole producer of M4A3E8 76 w Shermans, or the tank commonly known and the Easy 8. They produced 2617 units, but post war many A3 76 tanks were converted over to HVSS suspension. A very big chunk of the overall Sherman production came from this factory and it went on to produce M26 Pershing tanks. Chrysler built this factory in a suburb of Detroit, Warren Township Michigan. Chrysler used it’s many other facilities in the Detroit area as sub manufacturers, and many of their sub-contractors got involved too. CDA not only produced the tanks, it had the capacity to pump out huge numbers of spare parts. CDA lived into 90s before Chrysler defense systems got sold off to General Dynamics. It took part in making the M26, M46, M47, M48, M60 and M1 tanks. Federal Machine & Welder (FMW) I couldn’t find much out about FMW, Son of a Sherman says they were founded in Warren Ohio in 1917. They produced less than a thousand M4A2 small hatch tanks. They were slow to produce them, making about 50 a month. They were not contracted to make any more Shermans after their first 540 total, 1942 contract. They did build some M7, and M32 tank retrievers. They were out of business by the mid-fifties. Fisher Tank Arsenal (FTA) Fisher Tanks Arsenal (FTA) has a lot of common with Chrysler Defense Arsenal, except this time Uncle Sam went to Fisher Body, a division of General Motors. Fisher decided to build the tank plant in Grand Blanc, south of Flint Michigan. The factory broke ground in November of 1941 and the first M4A2 Sherman rolled off the line in January of 1942, before the factory was fully built. The M4A2 was something of this factory specialty, in particular early on, with them producing a large number of the small hatch M4A2 sent off to Russia, and a few of the rarer large hatch 75mm gun tanks, around 986 small hatch tanks, and about 286 large hatch tanks. They also produced nearly 1600 large hatch, 76mm gun tanks, or the M4A2 (76)w. These tanks went exclusively to Russia as part of Lend Lease. These tanks were ordered over four different contracts and the final ones off the production line were all HVSS tanks. The HVSS suspension may have seen combat with the Russians before the US Army used it. Oddly, this factory also produced M4A3 76w tanks, but never with the HVSS suspension. Fisher produced a significant number M4A3 and Large hatch 75mm tanks at their factory, but nowhere near their M4A2 production. Ford Motor Company (FMC) Ford was a surprisingly small player in the Sherman tale. They are very important in that they developed the Ford GAA V8 covered earlier, and a lot of spare parts. But they only produced 1690 small hatch Shermans between June of 42 and Oct 43. They built a few M10s as well. All these tanks and tank destroyers were produced at their Highland Park facility. After 1943, they stopped building tanks, and wouldn’t get back into until the 50s, and even then it was just for a large production run over a short time, of M48s. Lima Locomotive Works (LLW) Lima was one of the first producers of the cast hull M4A1. It did not produce any Lee tanks. Its production capacity had been taken by locomotives to the point just before Sherman production started. They produced the first production M4A1, that was shipped to England, named ‘Michael’, and it’s still on display at the Bovington Museum. They produced Shermans from February of 42, to September of 1943, producing M4A1s exclusively, and they built 1655 tanks. The war was a boon for Lima, they’d been in business since 1870, and the contracts from the military for locomotives really helped them out. Post war, they failed to successfully convert to diesel electric locomotives and merged with another firm. Montreal Locomotive Works (MCW) MLW was owned by American Locomotive. They produced some wacky Canadian tank based off the Lee chassis, called the Ram, and Ram II, these floppy creations were only armed with a 2 pounder in the Rams case, and a 6 pounder, in the Ram IIs case, and they produced almost 2000 of the wacky things, what’s that all aboot? They eventually got around to producing a proper Sherman tank, the M4A1 “Grizzly”, producing only about 188 tanks. A very few had an all metal track system that required a different sprocket. Other than that, there was no difference between a grizzly and an M4A1 manufactured by any other Sherman builder. Don’t believe the Canadian propaganda about it having thicker armor! Pacific Car & Foundry (PCF) PCF was founded in 1905 in Bellevue Washington. The only west coast tank maker, PCF produced 926 M4A1s from May of 1942, to November of 1943. As soon as production stopped they started production on the M26 tractor, the truck portion of the M26 tank transporter. They never got back into tank production, but still exist today as PACCAR Inc., one of the largest truck makers in the world. Pressed Steel Car (PST) PSC was one of the big boys of Sherman production, and they also produced the final M4s made, a group of 30 M4A1 76 HVSS tanks. PSC was founded in Pittsburg in 1899, but their tank factory was in Joliet, Illinois. They were the second manufacturer to make the tank and across all the versions they made, they produced 8147 Sherman tanks. They started tank production with the M3 Lee in June of 41, and stopped production on that in August of 1942. They then produced the M4A1 from March of 42, to December of 43, and the standard M4 from October of 42 to August of 43. They were one of the final three tank makers to stay in the tank making business after 1943, along with CDA and FTA. PSC would produce large hatch M4A1 76 tanks, including HVSS models late in the run, totaling more than 3400 M4A1 tanks. They produced 21, M4A2 76 HVSS tanks, towards the end of 45. They were out of business by 56, with no tank production after those final 30 M4A1 76 HVSS tanks. Pullman Standard (PSCC) Pullman Standard was a pretty famous luxury train passenger car maker, and another company that made rolling stock combined into one company. Pullman Palace Car Co was founded in 1867, or there about. I’m sure some train geek will be dying to fill me in on the company’s history but I’m not really going to look deeply into it. It does make for one of the more interesting stories about a Sherman tank producer. Their main tank factory was in Butler, Pennsylvania. And they helped produce some Grant tanks before they started Sherman production. They produced the M4A2 from April of 42 to September of 43, and produced 2737 tanks. They also produced 689 standard M4 Sherman tanks from May of 43, to September of 43. Soon after these contracts were finished the US Government broke the company up due to some anti-trust complaint. … The thing to remember about all the Sherman makers is each one had a small imprint on the tanks they produced. So, yes, an M4A1 small hatch tank was the same no matter who made it and all parts would interchange with no modification needed, but the tanks from different makers still had small, cosmetic differences. They may have been something like nonstandard hinges on the rear engine doors to the use of built up antenna mounts instead of cast. Or wide drivers hoods or narrow, to where the lift rings on the hull were and how they were made or even Chrysler's unique drive sprocket they put on all their post A4 tanks. None of this meant the parts couldn't be salvaged and used on another Sherman from another factory without much trouble. Some factories may have produced tanks faster than others, but they all produced them within the contracts specification or they were not accepted.
  6. 14 points
    I've been meditating a lot lately on humans that I hate. I would say "people I hate," but once I take to hating a someone enough I de-classify them as a person. I've been focusing on hate more because I've realized that there is no point in marinating in negative emotions. What I had mistaken for righteous indignation was really jealousy. I'm not angry at the fraudulent because I hate fraud; I'm angry because they're talentless hacks and I could do a far better job. But I'm lazy, so you, my talented reader, you must do a better job, and become a more ravenous, vicious, and unstoppable leech than ever these mediocre reprobates could dream. I got the idea when I was reading the latest drivel from our favorite poly sci majors, and I realized that the authors are fundamentally parasitic con artists, and, more to the point, half-assed ones. The article is only worth reading if you want to heckle it. It has no factual content. The funniest part is probably where they're talking up the threat of firearms made on 3D printers, and then bring up the Ghost Gunner, which isn't a 3D printer. It's a fucking mill. You know, an example of that old-fashioned subtractive manufacture that's supposed to be obsolete now. This is as intellectually honest as hyping the threat of being stung to death by zebras in the streets, and pointing out that tapirs will bite your fucking arm off as evidence of the severity of the threat. I am, of course, heartened to see that these worms have doubled down on their claim that 3D printing is somehow applicable to clandestine manufacture of nuclear weapons, and are, as before, aggressively misunderstanding fundamental facts about isotope enrichment. If there's anything that these scum are good at, it's ignoring basic fucking nuclear physics. But other than that, it's not a particularly slick attempt to sew panic and profit thereby. The best possible result from this sort of scaremongering is that some useless government regulatory agency will be set up to strangle 3D printing with useless regulations. This useless agency will have some number of jobs that will be filled with poly sci majors and other unemployable refuse. Anyone employed in this hypothetical useless agency would work nine to five in a cubicle, watching whatever their favorite deviant sort of porn is, calling in sick about a third of the time, and occasionally writing internal correspondence that will be beautifully devoid of meaning. Is this sort of soul-raping mediocrity anyone's idea of a big steal? Because if getting a fake job at a fake agency to police a fake threat is your notion of making it, please enclose yourself in a running incinerator. You have some sort of pathogen that causes you to aspire to being a moderate nuisance, and that sort of plague needs to stop now. The problem with these people is that their lies are small. As we all know, big lies are better than little ones. Don't stretch the truth; snap it right the fuck off. The only thing standing between you and gigantic yachts made of cocaine is a sentimental attachment to the truth. The lord of this world will only reward you fully if you embrace him fully. Highly successful liars don't embroider the truth, they dispense with it entirely. Consummate your marriage to darkness and falsity, and receive glorious rewards. Don't say that the Eisenhower administration should have been more aggressive in defense spending and research. Say that the Soviets have more bombers and more missiles. You'll get to be president of Camelot, fuck Marilyn Monroe and will be spared the indignity of old age. Don't say that 3D printing could change the way nuclear weapons are made in the future. Claim that the Iranians and North Koreans, and hell, that the South Africans all made their nuclear weapons by using 3D printers. When asked for evidence of your nonsense, point to the South African invasion of Sudan. Say so with absolute arrogance and an unshakable air of moral superiority. If you are loud and persistent enough, and lie outrageously enough, Satan will come through. Don't shill for big coal companies by claiming that coal gasification technology will improve atmospheric conditions. That's only stretching the truth. You've got to go all the way, and just burn regular coal that you painted with Elmer's glue. Your enemies will end up under review, and you'll get millions in tax credits. Satan delivers. Praise Satan. But you have to be willing to go all the way with Satan. Satan despises spineless, cowering wretches who sin a little to get ahead but still consider themselves fundamentally decent people. Satan came through for the solar roadways bastards. Satan came through for Leroy Jenkins. Trust in Satan, and you will excel. Don't you trust Satan? Do you think that Satan is ignorant of your duplicity? You cannot serve two masters. Drink deep or taste not.
  7. 13 points
    Hello, my friends and Kharkovites, take a sit and be ready for your brains to start to work - we are going to tell you a terrible secret of how to tell apart Soviet tanks that actually works like GLORIOUS T-80 and The Mighty T-72 from Kharkovites attempt to make a tank - the T-64. Many of capitalists Westerners have hard time understanding what tank is in front of them, even when they know smart words like "Kontakt-5" ERA. Ignoramus westerners! Because you are all were raised in several hundreds years old capitalism system all of you are blind consumer dummies, that need big noisy labels and shiny colorful things to be attached to product X to be sold to your ignorant heads and wallets, thats why we will need to start with basics. BASICS, DA? First - how to identify to which tank "family" particular MBT belongs to - to T-64 tree, or T-72 line, or Superior T-80 development project, vehicles that don't have big APPLE logo on them for you to understand what is in front of you. And how you can do it in your home without access to your local commie tank nerd? Easy! Use this Putin approved guide "How to tell appart different families of Soviet and Russian tanks from each other using simple and easy to spot external features in 4 steps: a guide for ignorant western journalists and chairborn generals to not suck in their in-depth discussions on the Internet". Chapter 1: Where to look, what to see. T-64 - The Ugly Kharkovite tank that doesn't work We will begin with T-64, a Kharkovite attempt to make a tank, which was so successful that Ural started to work on their replacement for T-64 known as T-72. Forget about different models of T-64, let's see what is similar between all of them. T-72 - the Mighty weapon of Workers and Peasants to smash westerners Unlike tank look-alike, made by Kharkovites mad mans, T-72 is true combat tank to fight with forces of evil like radical moderate barbarians and westerners. Thats why we need to learn how identify it from T-64 and you should remember it's frightening lines! The GLORIOUS T-80 - a Weapon to Destroy and Conquer bourgeois countries and shatter westerners army And now we are looking at the Pride of Party and Soviet army, a true tank to spearhead attacks on decadent westerners, a tank that will destroy countries by sucking their military budgets and dispersing their armies in vortex of air, left from high-speed charge by the GLORIOUS T-80! The T-80 shooting down jets by hitting them behind the horizont
  8. 13 points
    AAV-P7A1 CATFAE (Catapult launched Fuel Air Explosives). Troop carrying capabilities were exchanged for 21 fuel-air ordnance launchers for the purpose of clearing minefields and other obstacles during an amphibious assault.
  9. 13 points
    I forgot to post out my reference: JACAR C14011075200 JACAR C13120839500 Tomio Hara: "Japanese tank" Gakken: "Tank and Gun Tank" KAMADO: "Japanese Heavy Tanks" and help from Mr.Taki.
  10. 13 points
    *cracks fingers* Something that has interested me for a while, are shape stabilised projectiles. As in, projectiles that are stable due to their shape. Everybody has heard of rotation stabilised and fin stabilised projectiles, but shape stabilised is kind of different. I guess most of you here have seen shape stabilised projectiles without actually knowing how and why they work. Geek sidenote: Fin stabilised projectiles are actually fin and rotation stabilised. As I said, shape stabilised projectile have a stable flight path due to their unique shape. Figure 1: A 84mm Carl Gustav shape stabilised HEAT-round Note the slightly ogive front and the stand-off, which are characteristic of shape stabilised projectiles (SSP). Both features are absolutely crucial for the SSP to work. I'm going to throw you guys into the deep end by showing a .gif of the airflow in front of an SSP. Here's a link because I can't embed .gifv apparently The first thing you should notice is the air circulating in some-sort of pocket, and that this airflow is subsonic. Before I continue, here's the airflow in front of a blunt projectile: Clicketyclick While that projectile has a subsonic airflow in front of it as well, it is not circulating. Here's the airspeed of both projectiles as a normal picture: Figure 2: Airspeed in front of an SSP Figure 3: Airspeed in front of a blunt projectile It's clear that an SSP has a ogive-shaped subsonic airpocket in front of the projectile. This basically emulates the ogive of a normal rotation stabilised projectile. In other words, it makes it more aerodynamic. But does that airpocket stabilise the projectile? No it does not. So why is this projectile stabilised? The key is in what happens when it starts to tumble. Right now, there is nothing stopping the projectile from tumbling, and that's the interesting thing. There is literally nothing stopping the projectile from tumbling, except... the projectile itself. Lets take a look at what happens when an SSP starts to tumble. (If I remember correctly, I rotated the projectile 10 degrees) First off, the airflow in front of the projectile. It's fairly obvious that the airflow has changed. Lets check that again, but this time as a picture. Figure 4: Airflow in front of a tumbling SSP Again, it's obvious that the airflow has changed. The subsonic pocket has mainly shifted to one side and the air itself isn't really circulating in the pocket. This change causes a huge change in the Cd of the projectile. Let me show you why. Figure 5: Pressure in front of a tumbling SSP Next, the pressure in front of an SSP flying straight. Figure 6: Pressure in front of an SSP flying straight Please note the approximate pressure in front of both projectiles. The tumbling projectile has, on one side, twice the pressure as the projectile that's flying straight. Very interesting. What's even more interesting is that the pressure occurs on the opposite of the side it's turning to! The projectile is turning upwards, but the pressure builds up at the bottom. This pressure forces the projectile to start turning down again, forcing the projectile in a state where the pressure on all sides is equal. Voila, a shape stabilised projectile. But... why does it work? The subsonic airpocket is created by the stand-off and that little flange, or whatever you want to call it. The dimensions and placement of both are equally important. The stand-off and its side create the airpocket and the flange give the airpocket the required shape. The stand-off size can vary, but the flange size and placement is very important. If the flange is too far forward or too far back, the airpocket will be either too small or too big. Why does the size of the pocket matter? Because of this: Figure 7: Subsonic pocket in front of an SSP I changed the parameters slightly and made all airflow above Mach 1 red. Whatever is not red, is trans- or subsonic. The interesting thing to note here, is the pocket extends to the edge of the projectile (if I made the projectile better it should be exactly on the edge). (Sidenote: Here's the same picture of an SSP at a 10° angle) While the airpocket does not start at the flange, the flange determines where the pocket starts. If, at this velocity, the flange was further back, there would be supersonic flow hitting the front of the projectile, massively increasing drag. If the flange was further forward, the airpocket would be further forward too. This would mean the airpocket would not end at the edge of the projectile, but further out. Creating an airpocket which is wider than the projectile. This would allow the projectile to tumble a bit, because pressures wouldn't change much unless there is supersonic flow hitting the projectile. It is also possible to change the size of the airpocket by changing the front of the projectile itself. If the radius connecting the front and the stand-off is too big, the airflow inside the pocket would disrupt the circulation. The same would happen if the radius is too small. The angle of the front is important as well, but I haven't expermented that much with it so I don't know how important it exactly is, but it has an effect on the airflow. By the way, if the flange did not exist at all, the airpocket would start at around a third to half of the stand-off. Which would completely ruin the airpocket. Without a flange, the stand-off itself would have to be way bigger and longer to create the same kind of airpocket. But Bronezhilet, I hear you cry, if the airspeed changes, the pocket changes as well! I'm glad you brought that up, because you are right. A shape stabilised projectile only works properly within a certain flight envelope. If the projectile is moving too fast, the airpocket would compress allowing supersonic flow to hit the front of the projectile. Which in turns increases drag. By a lot. If the projectile is moving too slow the airpocket widens, allowing the projectile to tumble a bit before it would stabilise. I've been brainstorming with Colli a bit, and we've come to the conclusion that is why some projectiles are both shape stabilised and fin stabilised. When the projectile is moving too slow for shape stabilisation, the fins would keep it pointing in the right direction. And that concludes today's lesson. Thank you for reading.
  11. 12 points
    LostCosmonaut

    J2M Raiden

    Compared to the most well known Japanese fighter of World War 2, the A6M “Zero”, the J2M Raiden (“Jack”) was both less famous and less numerous. More than 10,000 A6Ms were built, but barely more than 600 J2Ms were built. Still, the J2M is a noteworthy aircraft. Despite being operated by the Imperial Japanese Navy (IJN), it was a strictly land-based aircraft. The Zero was designed with a lightweight structure, to give extreme range and maneuverability. While it had a comparatively large fuel tank, it was lightly armed, and had virtually no armor. While the J2M was also very lightly built, it was designed that way to meet a completely different set of requirements; those of a short-range interceptor. The J2M's design led to it being one of the fastest climbing piston-engine aircraft in World War 2, even though its four 20mm cannons made it much more heavily armed than most Japanese planes. Development of the J2M began in October 1938, under the direction of Jiro Hirokoshi, in response to the issuance of the 14-shi interceptor requirement (1). Hirokoshi had also designed the A6M, which first flew in April 1939. However, development was slow, and the J2M would not make its first flight until 20 March 1942, nearly 3 ½ years later (2). Initially, this was due to Mitsubishi's focus on the A6M, which was further along in development, and of vital importance to the IJN's carrier force. Additionally, the J2M was designed to use a more powerful engine than other Japanese fighters. The first aircraft, designated J2M1, was powered by an MK4C Kasei 13 radial engine, producing 1430 horsepower from 14 cylinders (3) (compare to 940 horsepower for the A6M2) and driving a three bladed propeller. The use of such a powerful engine was driven by the need for a high climb rate, in order to fulfill the requirements set forth in the 14-shi specification. The climb rate of an aircraft is driven by specific excess power; by climbing an aircraft is gaining potential energy, which requires power to generate. Specific Excess Power is given by the following equation; (Airspeed*(Thrust-Drag))/Weight It is clear from this equation that weight and drag must be minimized, while thrust and airspeed are maximized. The J2M was designed using the most powerful engine then available, to maximize thrust. Moreover, the engine was fitted with a long cowling, with the propeller on an extension shaft, also to minimize drag. In a more radical departure from traditional Japanese fighter design (as exemplified by aircraft such as the A6M and Ki-43), the J2M had comparatively short, stubby wings, only 10.8 m wide on the J2M3 variant, with a relatively high wing loading of 1.59 kN/m2 (33.29 lb/ft2) (2). (It should be noted that this wing loading is still lower than contemporary American aircraft such as the F6F Hellcat. The small wings reduced drag, and also reduced weight. More weight was saved by limiting the J2M's internal fuel, the J2M3 had only 550 liters of internal fuel (2). Hirokoshi did add some weight back into the J2M's design. 8 millimeters of steel armor plate protected the pilot, a luxurious amount of protection compared to the Zero. And while the J2M1 was armed with the same armament as the A6M (two 7.7mm machine guns and two Type 99 Model 2 20mm cannons), later variants would be more heavily armed, with the 7.7mm machine guns deleted in favor of an additional pair of 20mm cannons. Doubtlessly, this was driven by Japanese wartime experience; 7.7mm rounds were insufficient to deal with strongly built Grumman fighters, let alone a target like the B-17. The first flight of the J2M Raiden was on March 20th, 1942. Immediately, several issues were identified. One design flaw pointed out quickly was that the cockpit design on the J2M1, coupled with the long cowling, severely restricted visibility. (This issue had been identified by an IJN pilot viewing a mockup of the J2M back in December 1940 (1).) The landing speed was also criticized for being too high; while the poor visibility over the nose exacerbated this issue, pilots transitioning from the Zero would be expected to criticize the handling of a stubby interceptor. Wrecked J2M in the Philippines in 1945. The cooling fan is highly visible. However, the biggest flaw the J2M1 had was poor reliability. The MK4C engine was not delivering the expected performance, and the propeller pitch control was unreliable, failing multiple times. (1) As a result, the J2M1 failed to meet the performance set forth in the 14-shi specification, achieving a top speed of only 577 kph, well short of the 600 kph required. Naturally, the climb rate suffered as well. Only a few J2M1s were built. The next version, the J2M2, had several improvements. The engine was updated to the MK4R-A (3); this engine featured a methanol injection system, enabling it to produce up to 1,800 horsepower for short periods. The propeller was switched for a four blade unit. The extension shaft in the J2M1 had proved unreliable, in the J2M2 the cowling was shortened slightly, and a cooling fan was fitted at the the front. These modifications made the MK4R-A more reliable than the previous engine, despite the increase in power. However, there were still problems; significant vibrations occurred at certain altitudes and speeds; stiffening the engine mounts and propeller blades reduced these issues, but they were never fully solved (1). Another significant design flaw was identified in the summer of 1943; the shock absorber on the tail wheel could jam the elevator controls when the tailwheel retracted, making the aircraft virtually uncontrollable. This design flaw led to the death of one IJN pilot, and nearly killed two more (1). Ultimately, the IJN would not put the J2M2 into service until December 1943, 21 months after the first flight of the J2M1. 155 J2M2s would be built by Mitsubishi (3). By the time the J2M2 was entering service, the J2M3 was well into testing. The J2M3 was the most common variant of the Raiden, 260 were produced at Mitsubishi's factories (3). It was also the first variant to feature an armament of four 20mm cannons (oddly, of two different types of cannon with significantly different ballistics (2); the 7.7mm machine guns were replace with two Type 99 Model 1 cannons). Naturally, the performance of the J2M3 suffered slightly with the heavier armament, but it still retained its excellent rate of climb. The Raiden's excellent rate of climb was what kept it from being cancelled as higher performance aircraft like the N1K1-J Shiden came into service. The J2M's was designed to achieve a high climb rate, necessary for its intended role as an interceptor. The designers were successful; the J2M3, even with four 20mm cannons, was capable of climbing at 4650 feet per minute (1420 feet per minute) (2). Many fighters of World War 2, such as the CW-21, were claimed to be capable of climbing 'a mile a minute', but the Raiden was one of the few piston-engine aircraft that came close to achieving that mark. In fact, the Raiden climbed nearly as fast as the F8F Bearcat, despite being nearly three years older. Additionally, the J2M could continue to climb at high speeds for long periods; the J2M2 needed roughly 10 minutes to reach 30000 feet (9100 meters) (4), and on emergency power (using the methanol injection system), could maintain a climb rate in excess of 3000 feet per minute up to about 20000 feet (about 6000 meters). Analysis in Source (2) shows that the J2M3 was superior in several ways to one of its most common opponents, the F6F Hellcat. Though the Hellcat was faster at lower altitudes, the Raiden was equal at 6000 meters (about 20000 feet), and above that rapidly gained superiority. Additionally, the Raiden, despite not being designed for maneuverability, still had a lower stall speed than the Hellcat, and could turn tighter. The J2M3 actually had a lower wing loading than the American plane, and had flaps that could be used in combat to expand the wing area at will. As shown in the (poorly scanned) graphs on page 39 of (2), the J2M possessed a superior instantaneous turn capability to the F6F at all speeds. However, at high speeds the sustained turn capability of the American plane was superior (page 41 of (2)). The main area the American plane had the advantage was at high speeds and low altitudes; with the more powerful R-2800, the F6F could more easily overcome drag than the J2M. The F6F, as well as most other American planes, were also more solidly built than the J2M. The J2M also remained plagued by reliability issues throughout its service life. In addition to the J2M2 and J2M3 which made up the majority of Raidens built, there were a few other variants. The J2M4 was fitted with a turbo-supercharger, allowing its engine to produce significantly more power at high altitudes (1). However, this arrangement was highly unreliable, and let to only two J2M4s being built. Some sources also report that the J2M4 had two obliquely firing 20mm Type 99 Model 2 cannons in the fuselage behind the pilot (3). The J2M5 used a three stage mechanical supercharger, which proved more reliable than the turbo-supercharger, and still gave significant performance increases at altitude. Production of the J2M5 began at Koza 21st Naval Air Depot in late 1944 (6), but ultimately only about 34 would be built (3). The J2M6 was developed before the J2M4 and J2M6, it had minor updates such as an improved bubble canopy, only one was built (3). Finally, there was the J2M7, which was planned to use the same engine as the J2M5, with the improvements of the J2M6 incorporated. Few, if any, of this variant were built (3). A total of 621 J2Ms were built, mostly by Mitsubishi, which produced 473 airframes (5). However, 128 aircraft (about 1/5th of total production), were built at the Koza 21st Naval Air Depot (6). In addition to the reliability issues which delayed the introduction of the J2M, production was also hindered by American bombing, especially in 1945. For example, Appendix G of (5) shows that 270 J2Ms were ordered in 1945, but only 116 were produced in reality. (Unfortunately, sources (5) and (6) do not distinguish between different variants in their production figures.) Though the J2M2 variant first flew in October 1942, initial production of the Raiden was very slow. In the whole of 1942, only 13 airframes were produced (5). This included the three J2M1 prototypes. 90 airframes were produced in 1943, a significant increase over the year before, but still far less than had been ordered (5), and negligible compared to the production of American types. Production was highest in the spring and summer of 1944 (5), before falling off in late 1944 and 1945. The initial J2M1 and J2M2 variants were armed with a pair of Type 97 7.7mm machine guns, and two Type 99 Model 2 20mm cannons. The Type 97 used a 7.7x56mm rimmed cartridge; a clone of the .303 British round (7). This was the same machine gun used on other IJN fighters such as the A5M and A6M. The Type 99 Model 2 20mm cannon was a clone of the Swiss Oerlikon FF L (7), and used a 20x101mm cartridge. The J2M3 and further variants replaced the Type 97 machine guns with a pair of Type 99 Model 1 20mm cannons. These cannons, derived from the Oerlikon FF, used a 20x72mm cartridge (7), firing a round with roughly the same weight as the one used in the Model 2 at much lower velocity (2000 feet per second vs. 2500 feet per second (3), some sources (7) report an even lower velocity for the Type 99). The advantage the Model 1 had was lightness; it weighed only 26 kilograms vs. 34 kilograms for the model 2. Personally, I am doubtful that saving 16 kilograms was worth the difficulty of trying to use two weapons with different ballistics at the same time. Some variants (J2M3a, J2M5a) had four Model 2 20mm cannons (3), but they seem to be in the minority. In addition to autocannons and machine guns, the J2M was also fitted with two hardpoints which small bombs or rockets could be attached to (3) (4). Given the Raiden's role as an interceptor, and the small capacity of the hardpoints (roughly 60 kilograms) (3), it is highly unlikely that the J2M was ever substantially used as a bomber. Instead, it is more likely that the hardpoints on the J2M were used as mounting points for large air to air rockets, to be used to break up bomber formations, or ensure the destruction of a large aircraft like the B-29 in one hit. The most likely candidate for the J2M's rocket armament was the Type 3 No. 6 Mark 27 Bomb (Rocket) Model 1. Weighing 145 pounds (65.8 kilograms) (8), the Mark 27 was filled with payload of 5.5 pounds of incendiary fragments; upon launch it would accelerate to high subsonic speeds, before detonating after a set time (8). It is also possible that the similar Type 3 No. 1 Mark 28 could have been used; this was similar to the Mark 27, but much smaller, with a total weight of only 19.8 pounds (9 kilograms). The first unit to use the J2M in combat was the 381st Kokutai (1). Forming in October 1943, the unit at first operated Zeros, though gradually it filled with J2M2s through 1944. Even at this point, there were still problems with the Raiden's reliability. On January 30th, a Japanese pilot died when his J2M simply disintegrated during a training flight. By March 1944, the unit had been dispatched to Balikpapan, in Borneo, to defend the vital oil fields and refineries there. But due to the issues with the J2M, it used only Zeros. The first Raidens did not arrive until September 1944 (1). Reportedly, it made its debut on September 30th, when a mixed group of J2Ms and A6Ms intercepted a formation of B-24s attacking the Balikpapan refineries. The J2Ms did well for a few days, until escorting P-47s and P-38s arrived. Some 381st Raidens were also used in defense of Manila, in the Phillipines, as the Americans retook the islands. (9) By 1945, all units were ordered to return to Japan to defend against B-29s and the coming invasion. The 381st's J2Ms never made it to Japan; some ended up in Singapore, where they were found by the British (1). least three units operated the J2M in defense of the home islands of Japan; the 302nd, 332nd, and 352nd Kokutai. The 302nd's attempted combat debut came on November 1st, 1944, when a lone F-13 (reconaissance B-29) overflew Tokyo (1). The J2Ms, along with some Zeros and other fighters, did not manage to intercept the high flying bomber. The first successful attack against the B-29s came on December 3rd, when the 302nd shot down three B-29s. Later that month the 332nd first engaged B-29s attacking the Mitsubishi plant on December 22nd, shooting down one. (1) The 352nd operated in Western Japan, against B-29s flying out of China in late 1944 and early 1945. At first, despite severe maintenace issues, they achieved some successes, such as on November 21st, when a formation of B-29s flying at 25,000 feet was intercepted. Three B-29s were shot down, and more damaged. In general, when the Raidens were able to get to high altitude and attack the B-29s from above, they were relatively successful. This was particularly true when the J2Ms were assigned to intercept B-29 raids over Kyushu, which were flown at altitudes as low as 16,000 feet (1). The J2M also had virtually no capability to intercept aircraft at night, which made them essentially useless against LeMay's incendiary raids on Japanese cities. Finally the arrival of P-51s in April 1945 put the Raidens at a severe disadvantage; the P-51 was equal to or superior to the J2M in almost all respects, and by 1945 the Americans had much better trained pilots and better maintained machines. The last combat usage of the Raiden was on the morning of August 15th. The 302nd's Raidens and several Zeros engaged several Hellcats from VF-88 engaged in strafing runs. Reportedly four Hellcats were shot down, for the loss of two Raidens and at least one Zero(1). Japan surrendered only hours later. At least five J2Ms survived the war, though only one intact Raiden exists today. Two of the J2Ms were captured near Manila on February 20th, 1945 (9) (10). One of them was used for testing; but only briefly. On its second flight in American hands, an oil line in the engine failed, forcing it to land. The aircraft was later destroyed in a ground collision with a B-25 (9). Two more were found by the British in Singapore (1), and were flown in early 1946 but ex-IJN personnel (under close British supervision). The last Raiden was captured in Japan in 1945, and transported to the US. At some point, it ended up in a park in Los Angeles, before being restored to static display at the Planes of Fame museum in California. Sources: https://www.docdroid.net/gDMQra3/raiden-aeroplane-february-2016.pdf#page=2 F6F-5 vs. J2M3 Comparison http://www.combinedfleet.com/ijna/j2m.htm http://www.wwiiaircraftperformance.org/japan/Jack-11-105A.pdf https://babel.hathitrust.org/cgi/pt?id=mdp.39015080324281;view=1up;seq=80 https://archive.org/stream/corporationrepor34unit#page/n15/mode/2up http://users.telenet.be/Emmanuel.Gustin/fgun/fgun-pe.html http://ww2data.blogspot.com/2016/04/imperial-japanese-navy-explosives-bombs.html https://www.pacificwrecks.com/aircraft/j2m/3008.html https://www.pacificwrecks.com/aircraft/j2m/3013.html https://www.pacificwrecks.com/aircraft/j2m/3014.html Further reading: An additional two dozen Raiden photos: https://www.worldwarphotos.info/gallery/japan/aircrafts/j2m-raiden/
  12. 12 points
    Collimatrix

    Trade-offs in WWII Fighter Design

    But if you try sometimes... Fighter aircraft became much better during the Second World War. But, apart from the development of engines, it was not a straightforward matter of monotonous improvement. Aircraft are a series of compromises. Improving one aspect of performance almost always compromises others. So, for aircraft designers in World War Two, the question was not so much "what will we do to make this aircraft better?" but "what are we willing to sacrifice?" To explain why, let's look at the forces acting on an aircraft: Lift Lift is the force that keeps the aircraft from becoming one with the Earth. It is generally considered a good thing. The lift equation is L=0.5CLRV2A where L is lift, CL is lift coefficient (which is a measure of the effectiveness of the wing based on its shape and other factors), R is air density, V is airspeed and A is the area of the wing. Airspeed is very important to an aircraft's ability to make lift, since the force of lift grows with the square of airspeed and in linear relation to all other factors. This means that aircraft will have trouble producing adequate lift during takeoff and landing, since that's when they slow down the most. Altitude is also a significant factor to an aircraft's ability to make lift. The density of air decreases at an approximately linear rate with altitude above sea level: Finally, wings work better the bigger they are. Wing area directly relates to lift production, provided that wing shape is kept constant. While coefficient of lift CL contains many complex factors, one important and relatively simple factor is the angle of attack, also called AOA or alpha. The more tilted an airfoil is relative to the airflow, the more lift it will generate. The lift coefficient (and thus lift force, all other factors remaining equal) increases more or less linearly until the airfoil stalls: Essentially what's going on is that the greater the AOA, the more the wing "bends" the air around the wing. But the airflow can only become so bent before it detaches. Once the wing is stalled it doesn't stop producing lift entirely, but it does create substantially less lift than it was just before it stalled. Drag Drag is the force acting against the movement of any object travelling through a fluid. Since it slows aircraft down and makes them waste fuel in overcoming it, drag is a total buzzkill and is generally considered a bad thing. The drag equation is D=0.5CDRV2A where D is drag, CD is drag coefficient (which is a measure of how "draggy" a given aircraft is), R is air density, V is airspeed and A is the frontal area of the aircraft. This equation is obviously very similar to the lift equation, and this is where designers hit the first big snag. Lift is good, but drag is bad, but because the factors that cause these forces are so similar, most measures that will increase lift will also increase drag. Most measures that reduce drag will also reduce lift. Generally speaking, wing loading (the amount of wing area relative to the plane's weight) increased with newer aircraft models. The stall speed (the slowest possible speed at which an aircraft can fly without stalling) also increased. The massive increases in engine power alone were not sufficient to provide the increases in speed that designers wanted. They had to deliberately sacrifice lift production in order to minimize drag. World War Two saw the introduction of laminar-flow wings. These were wings that had a cross-section (or airfoil) that generated less turbulent airflow than previous airfoil designs. However, they also generated much less lift. Watch a B-17 (which does not have a laminar-flow wing) and a B-24 (which does) take off. The B-24 eats up a lot more runway before its nose pulls up. There are many causes of aerodynamic drag, but lift on a WWII fighter aircraft can be broken down into two major categories. There is induced drag, which is caused by wingtip vortices and is a byproduct of lift production, and parasitic drag which is everything else. Induced drag is interesting in that it actually decreases with airspeed. So for takeoff and landing it is a major consideration, but for cruising flight it is less important. However, induced drag is also significant during combat maneuvering. Wing with a higher aspect ratio, that is, the ratio of the wingspan to the wing chord (which is the distance from the leading edge to the trailing edge of the wing) produce less induced drag. So, for the purposes of producing good cruise efficiency, reducing induced drag was not a major consideration. For producing the best maneuvering fighter, reducing induced drag was significant. Weight Weight is the force counteracting lift. The more weight an aircraft has, the more lift it needs to produce. The more lift it needs to produce, the larger the wings need to be and the more drag they create. The more weight an aircraft has, the less it can carry. The more weight an aircraft has, the more sluggishly it accelerates. In general, weight is a bad thing for aircraft. But for fighters in WWII, weight wasn't entirely a bad thing. The more weight an aircraft has relative to its drag, the faster it can dive. Diving away to escape enemies if a fight was not going well was a useful tactic. The P-47, which was extremely heavy, but comparatively well streamlined, could easily out-dive the FW-190A and Bf-109G/K. In general though, designers tried every possible trick to reduce aircraft weight. Early in the war, stressed-skin monocoque designs began to take over from the fabric-covered, built-up tube designs. The old-style construction of the Hawker Hurricane. It's a shit plane. Stressed-skin construction of the Spitfire, with a much better strength to weight ratio. But as the war dragged on, designers tried even more creative ways to reduce weight. This went so far as reducing the weight of the rivets holding the aircraft together, stripping the aircraft of any unnecessary paint, and even removing or downgrading some of the guns. An RAF Brewster Buffalo in the Pacific theater. The British downgraded the .50 caliber machine guns to .303 weapons in order to reduce weight. In some cases, however, older construction techniques were used at the war's end due to materials shortages or for cost reasons. The German TA-152, for instance, used a large amount of wooden construction with steel reinforcement in the rear fuselage and tail in order to conserve aluminum. This was not as light or as strong as aluminum, but beggars can't be choosers. Extensive use of (now rotten) wood in the rear fuselage of the TA-152 Generally speaking, aircraft get heavier with each variant. The Bf-109C of the late 1930s weighed 1,600 kg, but the Bf-109G of the second half of WWII had ballooned to over 2,200 kg. One notable exception was the Soviet YAK-3: The YAK-3, which was originally designated YAK-1M, was a demonstration of what designers could accomplish if they had the discipline to keep aircraft weight as low as possible. Originally, it had been intended that The YAK-1 (which had somewhat mediocre performance vs. German fighters) would be improved by installing a new engine with more power. But all of the new and more powerful engines proved to be troublesome and unreliable. Without any immediate prospect of more engine power, the Yakovlev engineers instead improved performance by reducing weight. The YAK-3 ended up weighing nearly 300 kg less than the YAK-1, and the difference in performance was startling. At low altitude the YAK-3 had a tighter turn radius than anything the Luftwaffe had. Thrust Thrust is the force propelling the aircraft forwards. It is generally considered a good thing. Thrust was one area where engineers could and did make improvements with very few other compromises. The art of high-output piston engine design was refined during WWII to a precise science, only to be immediately rendered obsolete by the development of jet engines. Piston engined aircraft convert engine horsepower into thrust airflow via a propeller. Thrust was increased during WWII primarily by making the engines more powerful, although there were also some improvements in propeller design and efficiency. A tertiary source of thrust was the addition of jet thrust from the exhaust of the piston engines and from Merideth Effect radiators. The power output of WWII fighter engines was improved in two ways; first by making the engines larger, and second by making the engines more powerful relative to their weight. Neither process was particularly straightforward or easy, but nonetheless drastic improvements were made from the war's beginning to the war's end. The Pratt and Whitney Twin Wasp R-1830-1 of the late 1930s could manage about 750-800 horsepower. By mid-war, the R-1830-43 was putting out 1200 horsepower out of the same displacement. Careful engineering, gradual improvements, and the use of fuel with a higher and more consistent octane level allowed for this kind of improvement. The R-1830 Twin Wasp However, there's no replacement for displacement. By the beginning of 1943, Japanese aircraft were being massacred with mechanical regularity by a new US Navy fighter, the F6F Hellcat, which was powered by a brand new Pratt and Whitney engine, the R-2800 Double Wasp. The one true piston engine As you can see from the cross-section above, the R-2800 has two banks of cylinders. This is significant to fighter performance because even though it had 53% more engine displacement than the Twin Wasp (For US engines, the numerical designation indicated engine displacement in square inches), the Double Wasp had only about 21% more frontal area. This meant that a fighter with the R-2800 was enjoying an increase in power that was not proportionate with the increase in drag. Early R-2800-1 models could produce 1800 horsepower, but by war's end the best models could make 2100 horsepower. That meant a 45% increase in horsepower relative to the frontal area of the engine. Power to weight ratios for the latest model R-1830 and R-2800 were similar, while power to displacement improved by about 14%. By war's end Pratt and Whitney had the monstrous R-4360 in production: This gigantic engine had four rows of radially-arranged pistons. Compared to the R-2800 it produced about 50% more power for less than 10% more frontal area. Again, power to weight and power to displacement showed more modest improvements. The greatest gains were from increasing thrust with very little increase in drag. All of this was very hard for the engineers, who had to figure out how to make crankshafts and reduction gear that could handle that much power without breaking, and also how to get enough cooling air through a giant stack of cylinders. Attempts at boosting the thrust of fighters with auxiliary power sources like rockets and ramjets were tried, but were not successful. Yes, that is a biplane with retractable landing gear and auxiliary ramjets under the wings. Cocaine is a hell of a drug. A secondary source of improvement in thrust came from the development of better propellers. Most of the improvement came just before WWII broke out, and by the time the war broke out, most aircraft had constant-speed propellers. For optimal performance, the angle of attack of the propeller blades must be matched to the ratio of the forward speed of the aircraft to the circular velocity of the propeller tips. To cope with the changing requirements, constant speed or variable pitch propellers were invented that could adjust the angle of attack of the propeller blades relative to the hub. There was also improvement in using exhaust from the engine and the waste heat from the engine to increase thrust. Fairly early on, designers learned that the enormous amount of exhaust produced by the engine could be directed backwards to generate thrust. Exhaust stacks were designed to work as nozzles to harvest this small source of additional thrust: The exhaust stacks of the Merlin engine in a Spitfire act like jet nozzles A few aircraft also used the waste heat being rejected by the radiator to produce a small amount of additional thrust. The Meredith Effect radiator on the P-51 is the best-known example: Excess heat from the engine was radiated into the moving airstream that flowed through the radiator. The heat would expand the air, and the radiator was designed to use this expansion and turn it into acceleration. In essence, the radiator of the P-51 worked like a very weak ramjet. By the most optimistic projections the additional thrust from the radiator would cancel out the drag of the radiator at maximum velocity. So, it may not have provided net thrust, but it did still provide thrust, and every bit of thrust mattered. For the most part, achieving specific design objectives in WWII fighters was a function of minimizing weight, maximizing lift, minimizing drag and maximizing thrust. But doing this in a satisfactory way usually meant emphasizing certain performance goals at the expense of others. Top Speed, Dive Speed and Acceleration During the 1920s and 1930s, the lack of any serious air to air combat allowed a number of crank theories on fighter design to develop and flourish. These included the turreted fighter: The heavy fighter: And fighters that placed far too much emphasis on turn rate at the expense of everything else: But it quickly became clear, from combat in the Spanish Civil War, China, and early WWII, that going fast was where it was at. In a fight between an aircraft that was fast and an aircraft that was maneuverable, the maneuverable aircraft could twist and pirouette in order to force the situation to their advantage, while the fast aircraft could just GTFO the second that the situation started to sour. In fact, this situation would prevail until the early jet age when the massive increase in drag from supersonic flight made going faster difficult, and the development of heat-seeking missiles made it dangerous to run from a fight with jet nozzles pointed towards the enemy. The top speed of an aircraft is the speed at which drag and thrust balance each other out, and the aircraft stops accelerating. Maximizing top speed means minimizing drag and maximizing thrust. The heavy fighters had a major, inherent disadvantage in terms of top speed. This is because twin engined prop fighters have three big lumps contributing to frontal area; two engines and the fuselage. A single engine fighter only has the engine, with the rest of the fuselage tucked neatly behind it. The turret fighter isn't as bad; the turret contributes some additional drag, but not as much as the twin-engine design does. It does, however, add quite a bit of weight, which cripples acceleration even if it has a smaller effect on top speed. Early-war Japanese and Italian fighters were designed with dogfight performance above all other considerations, which meant that they had large wings to generate large turning forces, and often had open cockpits for the best possible visibility. Both of these features added drag, and left these aircraft too slow to compete against aircraft that sacrificed some maneuverability for pure speed. Drag force rises roughly as a square function of airspeed (throw this formula out the window when you reach speeds near the speed of sound). Power is equal to force times distance over time, or force times velocity. So, power consumed by drag will be equal to drag coefficient times frontal area times airspeed squared times airspeed. So, the power required for a given maximum airspeed will be a roughly cubic function. And that is assuming that the efficiency of the propeller remains constant! Acceleration is (thrust-drag)/weight. It is possible to have an aircraft that has a high maximum speed, but quite poor acceleration and vice versa. Indeed, the A6M5 zero had a somewhat better power to weight ratio than the F6F5 Hellcat, but a considerably lower top speed. In a drag race the A6M5 would initially pull ahead, but it would be gradually overtaken by the Hellcat, which would eventually get to speeds that the zero simply could not match. Maximum dive speed is also a function of drag and thrust, but it's a bit different because the weight of the aircraft times the sine of the dive angle also counts towards thrust. In general this meant that large fighters dove better. Drag scales with the frontal area, which is a square function of size. Weight scales with volume (assuming constant density), which is a cubic function of size. Big American fighters like the P-47 and F4U dove much faster than their Axis opponents, and could pick up speed that their opponents could not hope to match in a dive. A number of US fighters dove so quickly that they had problems with localized supersonic airflow. Supersonic airflow was very poorly understood at the time, and many pilots died before somewhat improvisational solutions like dive brakes were added. Ranking US ace Richard Bong takes a look at the dive brakes of a P-38 Acceleration, top speed and dive speed are all improved by reducing drag, so every conceivable trick for reducing parasitic drag was tried. The Lockheed P-38 used flush rivets on most surfaces as well as extensive butt welds to produce the smoothest possible flight surfaces. This did reduce drag, but it also contributed to the great cost of the P-38. The Bf 109 was experimentally flown with a V-tail to reduce drag. V-tails have lower interference drag than conventional tails, but the modification was found to compromise handling during takeoff and landing too much and was not deemed worth the small amount of additional speed. The YAK-3 was coated with a layer of hard wax to smooth out the wooden surface and reduce drag. This simple improvement actually increased top speed by a small, but measurable amount! In addition, the largely wooden structure of the aircraft had few rivets, which meant even less drag. The Donier DO-335 was a novel approach to solving the problem of drag in twin-engine fighters. The two engines were placed at the front and rear of the aircraft, driving a pusher and a tractor propeller. This unconventional configuration led to some interesting problems, and the war ended before these could be solved. The J2M Raiden had a long engine cowling that extended several feet forward in front of the engine. This tapered engine cowling housed an engine-driven fan for cooling air as well as a long extension shaft of the engine to drive the propeller. This did reduce drag, but at the expense of lengthening the nose and so reducing pilot visibility, and also moving the center of gravity rearward relative to the center of lift. Designers were already stuffing the most powerful engines coming out of factories into aircraft, provided that they were reasonably reliable (and sometimes not even then). After that, the most expedient solution to improve speed was to sacrifice lift to reduce drag and make the wings smaller. The reduction in agility at low speeds was generally worth it, and at higher speeds relatively small wings could produce satisfactory maneuverability since lift is a square function of velocity. Alternatively, so-called laminar flow airfoils (they weren't actually laminar flow) were substituted, which produced less drag but also less lift. The Bell P-63 had very similar aerodynamics to the P-39 and nearly the same engine, but was some 80 KPH faster thanks to the new laminar flow airfoils. However, the landing speed also increased by about 40 KPH, largely sacrificing the benevolent landing characteristics that P-39 pilots loved. The biggest problem with reducing the lift of the wings to increase speed was that it made takeoff and landing difficult. Aircraft with less lift need to get to higher speeds to generate enough lift to take off, and need to land at higher speeds as well. As the war progressed, fighter aircraft generally became trickier to fly, and the butcher's bill of pilots lost in accidents and training was enormous. Turn Rate Sometimes things didn't go as planned. A fighter might be ambushed, or an ambush could go wrong, and the fighter would need to turn, turn, turn. It might need to turn to get into a position to attack, or it might need to turn to evade an attack. Aircraft in combat turn with their wings, not their rudders. This is because the wings are way, way bigger, and therefore much more effective at turning the aircraft. The rudder is just there to make the nose do what the pilot wants it to. The pilot rolls the aircraft until it's oriented correctly, and then begins the turn by pulling the nose up. Pulling the nose up increases the angle of attack, which increases the lift produced by the wings. This produces centripetal force which pulls the plane into the turn. Since WWII aircraft don't have the benefit of computer-run fly-by-wire flight control systems, the pilot would also make small corrections with rudder and ailerons during the turn. But, as we saw above, making more lift means making more drag. Therefore, when aircraft turn they tend to slow down unless the pilot guns the throttle. Long after WWII, Col. John Boyd (PBUH) codified the relationship between drag, thrust, lift and weight as it relates to aircraft turning performance into an elegant mathematical model called energy-maneuverability theory, which also allowed for charts that depict these relationships. Normally, I would gush about how wonderful E-M theory is, but as it turns out there's an actual aerospace engineer named John Golan who has already written a much better explanation than I would likely manage, so I'll just link that. And steal his diagram: E-M charts are often called "doghouse plots" because of the shape they trace out. An E-M chart specifies the turning maneuverability of a given aircraft with a given amount of fuel and weapons at a particular altitude. Turn rate is on the Y axis and airspeed is on the X axis. The aircraft is capable of flying in any condition within the dotted line, although not necessarily continuously. The aircraft is capable of flying continuously anywhere within the dotted line and under the solid line until it runs out of fuel. The aircraft cannot fly to the left of the doghouse because it cannot produce enough lift at such a slow speed to stay in the air. Eventually it will run out of sky and hit the ground. The curved, right-side "roof" of the doghouse is actually a continuous quadratic curve that represents centrifugal force. The aircraft cannot fly outside of this curve or it or the pilot will break from G forces. Finally, the rightmost, vertical side of the doghouse is the maximum speed that the aircraft can fly at; either it doesn't have the thrust to fly faster, or something breaks if the pilot should try. The peak of the "roof" of the doghouse represents the aircraft's ideal airspeed for maximum turn rate. This is usually called the "corner velocity" of the aircraft. So, let's look at some actual (ish) EM charts: Now, these are taken from a flight simulator, but they're accurate enough to illustrate the point. They're also a little busier than the example above, but still easy enough to understand. The gray plot overlaid on the chart consists of G-force (the curves) and turn radius (the straight lines radiating from the graph origin). The green doghouse shows the aircraft's performance with flaps. The red curve shows the maximum sustained turn rate. You may notice that the red line terminates on the X axis at a surprisingly low top speed; that's because these charts were made for a very low altitude confrontation, and their maximum level top could only be achieved at higher altitudes. These aircraft could fly faster than the limits of the red line show, but only if they picked up extra speed from a dive. These charts could also be overlaid on each other for comparison, but in this case that would be like a graphic designer vomiting all over the screen, or a Studio Killers music video. From these charts, we can conclude that at low altitude the P-51D enjoys many advantages over the Bf 109G-6. It has a higher top speed at this altitude, 350-something vs 320-something MPH. However, the P-51 has a lower corner speed. In general, the P-51's flight envelope at this altitude is just bigger. But that doesn't mean that the Bf 109 doesn't have a few tricks. As you can see, it enjoys a better sustained turn rate from about 175 to 325 MPH. Between those speed bands, the 109 will be able to hold on to its energy better than the pony provided it uses only moderate turns. During turning flight, our old problem induced drag comes back to haunt fighter designers. The induced drag equation is Cdi = (Cl^2) / (pi * AR * e). Where Cdi is the induced drag coefficient, Cl is the lift coefficient, pi is the irrational constant pi, AR is aspect ratio, or wingspan squared divided by wing area, and e is not the irrational constant e but an efficiency factor. There are a few things of interest here. For starters, induced drag increases with the square of the lift coefficient. Lift coefficient increases more or less linearly (see above) with angle of attack. There are various tricks for increasing wing lift nonlinearly, as well as various tricks for generating lift with surfaces other than the wings, but in WWII, designers really didn't use these much. So, for all intents and purposes, the induced drag coefficient will increase with the square of angle of attack, and for a given airspeed, induced drag will increase with the square of the number of Gs the aircraft is pulling. Since this is a square function, it can outrun other, linear functions easily, so minimizing the effect of induced drag is a major consideration in improving the sustained turn performance of a fighter. To maximize turn rate in a fighter, designers needed to make the fighter as light as possible, make the engine as powerful as possible, make the wings have as much area as possible, make the wings as long and skinny as possible, and to use the most efficient possible wing shape. You probably noticed that two of these requirements, make the plane as light as possible and make the wings as large as possible, directly contradict the requirements of good dive performance. There is simply no way to reconcile them; the designers either needed to choose one, the other, or come to an intermediate compromise. There was no way to have both great turning performance and great diving performance. Since the designers could generally be assumed to have reduced weight to the maximum possible extent and put the most powerful engine available into the aircraft, that left the design of the wings. The larger the wings, the more lift they generate at a given angle of attack. The lower the angle of attack, the less induced drag. The bigger wings would add more drag in level flight and reduce top speed, but they would actually reduce drag during maneuvering flight and improve sustained turn rate. A rough estimate of the turning performance of the aircraft can be made by dividing the weight of the aircraft over its wing area. This is called wing loading, and people who ought to know better put far too much emphasis on it. If you have E-M charts, you don't need wing loading. However, E-M charts require quite a bit of aerodynamic data to calculate, while wing loading is much simpler. Giving the wings a higher aspect ratio would also improve turn performance, but the designers hands were somewhat tied in this respect. The wings usually stored the landing gear and often the armament of the fighter. In addition the wings generated the lift, and making the wings too long and skinny would make them too structurally flimsy to support the aircraft in maneuvering flight. That is, unless they were extensively reinforced, which would add weight and completely defeat the purpose. So, designers were practically limited in how much they could vary the aspect ratio of fighter wings. The wing planform has significant effect on the efficiency factor e. The ideal shape to reduce induced drag is the "elliptical" (actually two half ellipses) wing shape used on the Supermarine spitfire. This wing shape was, however, difficult to manufacture. By the end of the war, engineers had come up with several wing planforms that were nearly as efficient as the elliptical wing, but were much easier to manufacture. Another way to reduce induced drag is to slightly twist the wings of the aircraft so that the wing tips point down. This is called washout. The main purpose of washout was to improve the responsiveness of the ailerons during hard maneuvering, but it could give small efficiency improvements as well. Washout obviously complicates the manufacture of the wing, and thus it wasn't that common in WWII, although the TA-152 notably did have three degrees of tip washout. The Bf 109 had leading edge slats that would deploy automatically at high angles of attack. Again, the main intent of these devices was to improve the control of the aircraft during takeoff and landing and hard maneuvering, but they did slightly improve the maximum angle of attack the wing could be flown at, and therefore the maximum instantaneous turn rate of the aircraft. The downside of the slats was that they weakened the wing structure and precluded the placement of guns inside the wing. leading edge slats of a Bf 109 in the extended position One way to attempt to reconcile the conflicting requirements of high speed and good turning capability was the "butterfly" flaps seen on Japanese Nakajima fighters. This model of a Ki-43 shows the location of the butterfly flaps; on the underside of the wings, near the roots These flaps would extend during combat, in the case of later Nakajima fighters, automatically, to increase wing area and lift. During level and high speed flight they would retract to reduce drag. Again, this would mainly improve handling on the left hand side of the doghouse, and would improve instantaneous turn rate but do very little for sustained turn rate. In general, turn performance was sacrificed in WWII for more speed, as the two were difficult to reconcile. There were a small number of tricks known to engineers at the time that could improve instantaneous turn rate on fast aircraft with high wing loading, but these tricks were inadequate to the task of designing an aircraft that was very fast and also very maneuverable. Designers tended to settle for as fast as possible while still possessing decent turning performance. Climb Rate Climb rate was most important for interceptor aircraft tasked with quickly getting to the level of intruding enemy aircraft. When an aircraft climbs it gains potential energy, which means it needs spare available power. The specific excess power of an aircraft is equal to V/W(T-D) where V is airspeed, W is weight, T is thrust and D is drag. Note that lift isn't anywhere in this equation! Provided that the plane has adequate lift to stay in the air and its wings are reasonably efficient at generating lift so that the D term doesn't get too high, a plane with stubby wings can be quite the climber! The Mitsubishi J2M Raiden is an excellent example of what a fighter optimized for climb rate looked like. A captured J2M in the US during testing The J2M had a very aerodynamically clean design, somewhat at the expense of pilot visibility and decidedly at the expense of turn rate. The airframe was comparatively light, somewhat at the expense of firepower and at great expense to fuel capacity. Surprisingly for a Japanese aircraft, there was some pilot armor. The engine was, naturally, the most powerful available at the time. The wings, in addition to being somewhat small by Japanese standards, had laminar-flow airfoils that sacrificed maximum lift for lower drag. The end result was an aircraft that was the polar opposite of the comparatively slow, long-ranged and agile A6M zero-sen fighters that IJN pilots were used to! But it certainly worked. The J2M was one of the fastest-climbing piston engine aircraft of the war, comparable to the F8F Bearcat. The design requirements for climb rate were practically the same as the design requirements for acceleration, and could generally be reconciled with the design requirements for dive performance and top speed. The design requirements for turn rate were very difficult to reconcile with the design requirements for climb rate. Roll Rate In maneuvering combat aircraft roll to the desired orientation and then pitch. The ability to roll quickly allows the fighter to transition between turns faster, giving it an edge in maneuvering combat. Aircraft roll with their ailerons by making one wing generate more lift while the other wing generates less lift. The physics from there are the same for any other rotating object. Rolling acceleration is a function of the amount of torque that the ailerons can provide divided by the moment of inertia of the aircraft about the roll axis. So, to improve roll rate, a fighter needs the lowest possible moment of inertia and the highest possible torque from its ailerons. The FW-190A was the fighter best optimized for roll rate. Kurt Tank's design team did everything right when it came to maximizing roll rate. The FW-190 could out-roll nearly every other piston fighter The FW-190 has the majority of its mass near the center of the aircraft. The fuel is all stored in the fuselage and the guns are located either above the engine or in the roots of the wings. Later versions added more guns, but these were placed just outside of the propeller arc. Twin engined fighters suffered badly in roll rate in part because the engines had to be placed far from the centerline of the aircraft. Fighters with armament far out in the wings also suffered. The ailerons were very large relative to the size of the wing. This meant that they could generate a lot of torque. Normally, large ailerons were a problem for pilots to deflect. Most World War Two fighters did not have any hydraulic assistance; controls needed to be deflected with muscle power alone, and large controls could encounter too much wind resistance for the pilots to muscle through at high speed. The FW-190 overcame this in two ways. The first was that, compared to the Bf 109, the cockpit was decently roomy. Not as roomy as a P-47, of course, but still a vast improvement. Cockpit space in World War Two fighters wasn't just a matter of comfort. The pilots needed elbow room in the cockpit in order to wrestle with the control stick. The FW-190 also used controls that were actuated by solid rods rather than by cables. This meant that there was less give in the system, since cables aren't completely rigid. Additionally, the FW-190 used Frise ailerons, which have a protruding tip that bites into the wind and reduces the necessary control forces: Several US Navy fighters, like later models of F6F and F4U used spring-loaded aileron tabs, which accomplished something similar by different means: In these designs a spring would assist in pulling the aileron one way, and a small tab on the aileron the opposite way in order to aerodynamically move the aileron. This helped reduce the force necessary to move the ailerons at high speeds. Another, somewhat less obvious requirement for good roll rate in fighters was that the wings be as rigid as possible. At high speeds, the force of the ailerons deflecting would tend to twist the wings of the aircraft in the opposite direction. Essentially, the ailerons began to act like servo tabs. This meant that the roll rate would begin to suffer at high speeds, and at very high speeds the aircraft might actually roll in the opposite direction of the pilot's input. The FW-190s wings were extremely rigid. Wing rigidity is a function of aspect ratio and construction. The FW-190 had wings that had a fairly low aspect ratio, and were somewhat overbuilt. Additionally, the wings were built as a single piece, which was a very strong and robust approach. This had the downside that damaged wings had to be replaced as a unit, however. Some spitfires were modified by changing the wings from the original elliptical shape to a "clipped" planform that ended abruptly at a somewhat shorter span. This sacrificed some turning performance, but it made the wings much stiffer and therefore improved roll rate. Finally, most aircraft at the beginning of the war had fabric-skinned ailerons, including many that had metal-skinned wings. Fabric-skinned ailerons were cheaper and less prone to vibration problems than metal ones, but at high speed the shellacked surface of the fabric just wasn't air-tight enough, and a significant amount of airflow would begin going into and through the aileron. This degraded their effectiveness greatly, and the substitution of metal surfaces helped greatly. Stability and Safety World War Two fighters were a handful. The pressures of war meant that planes were often rushed into service without thorough testing, and there were often nasty surprises lurking in unexplored corners of the flight envelope. This is the P-51H. Even though the P-51D had been in mass production for years, it still had some lingering stability issues. The P-51H solved these by enlarging the tail. Performance was improved by a comprehensive program of drag reduction and weight reduction through the use of thinner aluminum skin. The Bf 109 had a poor safety record in large part because of the narrow landing gear. This design kept the mass well centralized, but it made landing far too difficult for inexpert pilots. The ammunition for the massive 37mm cannon in the P-39 and P-63 was located in the nose, and located far forward enough that depleting the ammunition significantly affected the aircraft's stability. Once the ammunition was expended, it was much more likely that the aircraft could enter dangerous spins. The cockpit of the FW-190, while roomier than the Bf 109, had terrible forward visibility. The pilot could see to the sides and rear well enough, but a combination of a relatively wide radial engine and a hump on top of the engine cowling to house the synchronized machine guns meant that the pilot could see very little. This could be dangerous while taxiing on the ground.
  13. 12 points
    The mean goons over on SA roped me into writing an effortpost, so I figured it's only fair that you freeloaders get to enjoy it too. So, suspensions. I'm going to introduce the book as well because it's probably the most Soviet book that ever existed. It is called TANK. What makes this book so Soviet? Well, here's the first paragraph of the introduction: "Under the guidance of the Communist party of the Soviet Union, our people built socialism, achieved a historical victory in the Great Patriotic War, and in launched an enormous campaign for the creation of a Communist society." The next paragraph talks about the 19th Assembly of the CPSU, then a bit about how in the Soviet Union man no longer exploits man (now it's the other way around :haw:), then a little bit about the war again, then spends another three pages stroking the party's dick about production and growth. The word "tank" does not appear in the introduction. The historical prelude section is written by someone who is a little closer to tanks and might be a little less politically reliable, since they actually give Tsarists credit for things. I guess they have to, since foreigners are only mentioned in this section when they are amazed by Russian progress. The next chapter is a Wikipedia-grade summary of various tank designs that gives WWI designs a pretty fair evaluation, then a huge section on Soviet tank development, then a tiny section on foreign tanks in WWII mostly consisting of listing all the mistakes their designers made. The party must have recuperated since the intro since we're in for another three pages of fellatio. Having read so far, you might think that there is very little value in this sort of book, but then the writing style does a complete 180 and the rest of the book is 100% apolitical and mostly looks like this. Which is what we care about, so let's begin. Bonus points to anyone who can identify what the diagram above is about. Sorry in advance if my terminology isn't 100% correct, there aren't exactly a lot of tank dictionaries lying around. The book skips over primitive unsprung suspensions of WWI and starts off with describing the difference between independent suspensions and road-arm suspensions. In the former, every wheel is independently sprung. In the latter, two or more wheels are joined together by a spring. Some suspensions have a mix of these designs. For example, here's a simple road-arm suspension used in some Vickers designs and their derivatives. The two road wheels are connected by a spring and to the hull by a lever. A weight pushing down on top of the pair of wheels is going to compress the spring that's perpendicular to the ground, bringing the wheels closer together. Here's a more complex road-arm suspension, with four wheels per unit instead of one, also AFAIK first used by Vickers and then migrating to an enormous amount of designs from there. This suspension provides springiness through a leaf spring that you can see above the four road wheels. The two pairs of wheels don't have their own springs. The black circles in the image show where the suspension elements can turn, keeping the tank flat while hugging the terrain. Here's another road-arm suspension, similar to the first one. In this case, the spring is made of rubber instead of metal. Otherwise, the design is very similar. Two rubber bungs on the bottom of the axles prevent the wheels from slamming into each other too hard. This design was used by French tanks and nobody else. For some reason, volute spring suspensions are completely absent from this section. This is the best image of a Vertical Volute Spring Suspension (early Shermans) that I could find. It's kind of similar to the first image, except the spring is a volute spring, and it's vertical instead of horizontal. Later Shermans used horizontal volute springs. Of course, as the book points out, these suspension elements are very easy to damage externally and knocking out one part of the suspension will typically take out the rest of the assembly, so independent suspensions are the way to go. The best way to do this are torsion bars. The bar is attached to a lever that holds your road wheel. As pressure is applied to the road wheel, the bar subtly twists, remaining elastic enough to reset once the pressure is off. This image is kind of weird, but the part in the center is the part on the far left, zoomed in, showing you where the lever and the opposite side's torsion bar are attached. As you can see, road wheels in a torsion bar suspension are going to be a little off on one side, unlike what you're used to on cars and such. Now, since torsion bars are metal bars on the floor, they are going to make your tank taller. If you want a tank that's as short as possible at the expense of width, you may want to consider a Christie like suspension. Here, much like in torsion bars, the pressure is transferred inside the tank, but instead of a bar to absorb it, it's a spring in a vertical (or angled) tube. In most tanks with this kind of suspension, the springs are on the inside, but if you want to make the tank roomier on the inside, you can have them on the outside too. If you're really fancy, you can put a spring within the spring like in this diagram. Since this is a Soviet tank book, you gotta have a huge T-34 diagram. Here it is. The T-34 uses Christie springs, which you can see in the diagram. The road wheel configuration is a mix of the externally dampened and internally dampened "Stalingrad type" road wheels. The former have more rubber for absorbing hits from terrain, but the latter use less rubber. When you're in Stalingrad and you have to make tanks with a rubber deficit, that's the kind you want. When road wheels from other factories were available, they would go in the front and then the back to absorb most of the impact from harsh terrain features, and the steel-rimmed wheels went in the middle. The diagram shows how both types of wheels work. Rubber can't really take too much punishment, so the KV, being a heavy tank, went with internally dampened road wheels from the very beginning, with a ring of rubber on the inside around the axle. And finally, idlers. If you don't have big Christie type wheels, you gotta have idlers so your saggy track doesn't fall off. This diagram shows the rubber coating on an idler, and also how the rear idler can adjust to tighten the track. A loose track makes more noise, gets worn more, and is liable to slip off. Keep those tracks tight, and you'll be zooming towards glorious victory in no time flat! Now, the book ends and my own stuff begins. I mentioned rubber, but not what a headache it was to tank designers. In hot weather, the rubber in your tracks and wheels tends to fall apart. If you go fast enough, tires that don't have proper ventilation are going to melt too. There was a lot of pre-war panic in the USSR about the German PzIII being able to do 70 kph on tracks, but once the Soviets started building SU-76Is on the PzIII chassis they found out that the speed had to be limited to a whopping 25 kph to keep the wear to a reasonable level.
  14. 11 points
    Tied has been trying to get me to post here for months, and he has finally convinced me to join up. So without further ado here is a post I made on the SA forums since I see there isn't a T-80 thread. ________________________________________________________________________________ T-80 Program The T-80 MBT was another offshoot of the T-64 program. It entered service around the same time as the new generation of NATO tanks such as the Leopard 2, M1 Abrams and Challenger. While it was a capable and effective tank, it also carried a horrifically high price to deliver these qualities. Which considering the economic conditions of the USSR at the time of its introduction, could charitably be considered "negligent". To borrow a phrase, it was an example of "The best being the enemy of the good". Despite its problems, The T-80U was certainly aesthetic. Video "Made in the USSR: T-80 main battle tank". Origins The T-80 was a child of two lineages, primarily, the T-64 design from Kharkov, and secondly the various tank turbine engine projects that had existed in the USSR for decades. In 1971, the soviet tank industry began work on new designs that would replace the T-64 and T-72 after 1981. These new designs were nicknamed "Perspektivy" or "NST" from "New Standard Tank". There was a number of submissions, such as the unorthodox T-74 offered by Kharkov. Leningrad's Kirov KB offered the turbine powered Object 225 and the diesel Object 226, while Chelyabinsk offered the Object 780. Over time these projects were refined and replaced with the Leningrad Object 258, Chelyabinsk Object 785 and Kharkov adding the Object 480. Out of the three, only Kharkov remained enthusiastic about their project. Chelyabinsk had been moving away from the tank business after a change in management, and Leningrad had shifted their efforts onto a new T-64 remix, the Object 219T. After the problems with the T-64, along with Morozov's upcoming retirement, the army rejected the T-74. Turbines, a Primer. Interest in turbine engines for tanks had existed since the 1950's. Turbine technology offered engines that would be significantly smaller, lighter and more powerful than equivalent diesel engines. However they also had much higher requirements in terms of air filtering, maintenance and foremost, fuel. The appetites of a Turbine averaged at 240kg/hour of fuel to the 83kg/hour of a comparable diesel, a significant increase! These engines would also cost more than 10x equivalent diesels, an example figure is R9,600 for the V-46 to the R104,000 demanded of the GTD-1000. Object 219 Development The first experimental GTD-1000T turbine engine was mounted on a modified T-64 tank chassis. During early trials, it was found that the T-64 running gear would limit the top speed of the vehicle due to the extreme vibrations of the metal road wheels and the track at high speed. As a result, a new suspension was designed for the Obj.219 but with no attempted made to standardize this with the rival T-72's suspension. During trials from 1968 to 1971, various suspension and subcomponent options were explored. Dust ingestion was a significant problem for the new tank, leading to a redesign of the air filters and the fitting of rubber side skirts to reduce the amount of dust kicked up during movement. The Curse of the 5TDF lived on however and the engines had woefully low average times before failure, falling far below the targeted life of 500hrs. Trials also showed that the voracious fuel appetite of the engine forced the use of external fuel drums to meet the basic range requirement of 450km. Fuel consumption of the engine was an astounding 1.6 to 1.8 times higher than the T-64A. Wisely, Minister of Defense Andrei Grechko rejected plans to put the new Object 219 into production, citing that it offered no improvements to firepower or armor and consumed twice as much fuel as the T-64A. Unfortunately for the soviets, Grechko died in 1976 and replaced by Dmitry Ustinov, who immediately set about getting his pet project approved. Production was to start at LKZ and Omsk. Furthermore, any major tank system upgrades would be earmarked for priority use on the T-80 platform, such as new fire controls, stabilizers and etc. In the original production configuration, the much delayed T-80 was essentially a T-64A with a turbine engine and new suspension. In all other respects the vehicle was equivalent, armor, armament, fire control and etc. But not the price! The T-80 was hideously expensive at R480,000 to the R143,000 of the T-64A. Not to mention, the tank had already fallen behind the T-64's newest version; the T-64B (which cost R318,000 I might add). As a result, the T-80 did not last long in production, with about less than 200 tanks made between 1976 and 1978. T-80B Ustinov used his position to ensure that the T-80 would be the new standard tank of the Soviet Army, and it was imperative that the quality of its systems be brought up to the level of the T-64B. To achieve this, the systems of the T-64B turret such as the LRF, ballistic computer, autoloader, Kobra complex, and etc were adapted to a new T-80B turret. This turret used the same protective technology as well (combination-K) and offered the same protection. The hull was unchanged. This upgrade was designated the Object 219R. The T-80B would be the primary production variant of this tank. The T-80B was put into production in 1978 at LKZ and at Omsk in 1979. The T-80B would also later be fitted with Kontakt-1 ERA, Unfortunately there is not much to be said about the T-80B really as it was essentially a T-64B with a turbine engine that in cost more in total. T-80U The evolutionary links between the T-80B and what would become known as the T-80U were the Object 219A and 219V. The Object 219A would be a combination of a T-80B hull and a new T-64 turret that had been developed in Kharkov as another upgrade for their tank line, the Object 476. This time, rather than waste time and resources on another pissing match where a perfectly fine T-64 turret would be remade for the T-80, the turret was dropped in directly. This new combined effort would leave the LKZ responsible for the overall program, while Kharkov would continue to work on the turret and armament. The Object 476 turret included a new generation of technology, such as the 1A45 fire control system, a new 1G46 sight and new laminate armor in the turret. This new generation of Laminate armor had been developed at NII Stali, with two versions. A simpler “reflecting-plate” system that would be used in the T-72B. The Object 476 turret however used the more expensive “semi-active filled-cell” armor design. In this design, plates of steel were suspended in polymer filled cells backed by a plate of resin and another layer of resin. When penetrated by HEAT, the shockwaves from the detonation would cause the reverberation of the semi-liquid filler, degrading the penetrating jet. While the Object 219A was ready for production in 1982, only a handful were made for use in technology trials. The new tank would have to wait for new technology initiatives to bear fruit, such as the Refleks missile complex and Kontakt-5 ERA. The Refleks laser beam riding missile was a brother of the Svir mounted on the T-72B, and both had been based of the Bastion/Sheksna missiles developed for the T-55 and T-62 respectively. The Refleks and Svir offered the most penetration of all, at 700mm RHA equivalent, compared to the 600mm offered by Kobra. The range was also extended from 4km to 5km. Kontakt-5 ERA also provided an impressive degree of protection against HEAT, and in a first for ERA, against APFSDS rounds as well. Against KE rounds, it is claimed that it will degrade their performance by 20% to 35%. While integration of the object 476 turret with the 219A hull, the object 219V was fitted with a new GTD-1000F engine with a supercharger and the refleks missile complex. Both of these designs have been sometimes dubbed the T-80A, even though they were never accepted for service under this name. A new object 219AS merged the features of both the 219A and the 219V. Twenty were produced in late 1983 with eight sent for troop trials and the remainder used in factory and state trials. The Object 219AS was accepted for Soviet Army service in 1985 as the T-80U. Series production of this type began in 1987 at Omsk, which would be the primary producer of this type as production at LKZ had been winding down and Kharkov was busy retooling for the job. The T-80U would be the definitive version of this tank, and offered impressive protection against APFSDS (780mm), HEAT (1,320mm) on the turret front, a very high degree of cross country capability and high speed. However this astronomical performance also came with astronomical cost: a VNII Transmash study found that the T-80U offered only 10% improvement over the T-72B but cost 824,000Ru compared to only 280,000Ru; nearly three times more. After Ustinov popped his clogs in December 1984, his turbine fetish was finally pried from his cold, dead hands. The following death of Leningrad party-boss Romanov 7 months later in July 1985 removed the second major benefactor of the T-80 program. This cleared the way for a return to more conventional engines for the T-80. The pushback concerning turbine engines was focused primarily on cost. A GTD-1000 cost R104,000 which is ten times more than the R9,600 cost of the V-46 used in the T-72. Additionally, turbines had shorter running life, consumed an atrocious amount of fuel and were complicated and expensive to repair. Kharkov had been working on a diesel powered T-80 since 1976 (object 478), which used the new 6TD 1,000hp diesel that had been destined for the Object 476. This would be used in the new diesel powered T-80 Kharkov’s production of the T-80U had been limited, only reaching 45 until the government approved the creation of a new diesel powered T-80U. Kharkov had wanted to follow the tradition of the T-34, T-44, T-54 and T-64 and name the new tank the T-84. Their hopes were dashed and it was called the T-80UD (UD= Improved diesel), to avoid the embarrassment of acknowledging having not three, but actually four similar tanks in production. This slap fight over names had to actually go all the way up to Gorby’s desk in order to be resolved. The T-80UD was approved for trials in September 2nd, 1985 and for production in 1986. About 500 T-80UD were produced before the fall of the Soviet Union and eventually found life beyond death of revolution in one country, morphing into the Ukrainian T-84 program. ~Controversial Opinions Zone~ While I feel like I am about to trigger Lost Cosmonaut or T___A here. I feel that having now read about the tank I got say that I am flabbergasted and have no idea what the fuck the Soviets were thinking. The T-80 was a tank design that seemed to offer only the dubious benefit over its competition of a high speed and considerable power to weight ratio. While these two qualities may be very important on the tank show circuit, the famous “flying tank” demonstration, it is questionable just how much benefit this would confer over its older brothers the T-64 and T-72 on a real battlefield. Not to mention, this impressive performance came as a significant cost to fuel range. The engine would always be drawing the same quantity of fuel, be the tank rolling at maximum speed down a road or idling at a position. In short, and more technical terms, they were increasing their tactical mobility while severely compromising the operational mobility of the tank. When one considers that the armor and armament of the T-80U were effectively stolen from the T-64 program, and that the T-72 had managed to produce a roughly equivalent vehicle at a fraction of the cost, you have to ask, what was the point? The money and effort that had gone into the T-80 program would have been better spent on the T-64 and T-72 lines. Consider the benefits; T-64 could have been upgraded in line with the object 476 program which would have given a spiritual T-80UD much sooner. The T-72B could have received the upgraded fire controls, stabilizers and etc reserved for the T-80U that were eventually fitted anyway in the form of the T-72BU (aka T-90). Along this line of thought, the main thing that had been holding back the T-72 program was its designation as the “cheaper” line that was not deserving of the extra funding to turn a solid vehicle into a superior one (as what happened with the T-90). At the very least, you could justifiably assume that these options would be cheaper due to the lack of the expensive gas turbine. The only thing that I can really give separate praise for in my current impression was that the suspension. To what I gather, it is quite effective and offered a very smooth ride compared to the T-64 or T-72 suspension. But this system could have been adapted for either of these two tanks anyway which brings us back to the original question: what was the point, really? While the new generation of NATO tanks in the form of the Leopard 2, M1 Abrams and Challenger were a major step up, the soviets should have waited for a much more substantially improved design to appear, rather than making their bets with a fattened T-64 with a turbine stuck in it. While overall the tank was not a failure that we in the thread mock the Tiger2 for being (the T-80 at least didn’t set itself on fire, ho ho), it however does share the same fundamental problem in that it just wasn’t appropriate for the strategic needs of the state at the time of its production. It cost too much, consumed too much fuel and offered only mild performance increases over more workhorse designs
  15. 11 points
    Collimatrix

    Bash the EM-2 Thread

    Here at Sturgeon's House, we do not shy from the wholesale slaughter of sacred cows. That is, of course, provided that they deserve to be slaughtered. The discipline of Military Science has, perhaps unavoidably, created a number of "paper tigers," weapons that are theoretically attractive, but really fail to work in reality. War is a dangerous sort of activity, so most of the discussion of it must, perforce, remain theoretical. Theory and reality will at some point inevitably diverge, and this creates some heartaches for some people. Terminal, in some cases, such as all those American bomber crews who could never complete a tour of duty over Fortress Europe because the pre-war planners had been completely convinced that the defensive armament of the bombers would be sufficient to see them through. In other cases though, the paper tiger is created post-facto, through the repetition of sloppy research without consulting the primary documents. One of the best examples of a paper tiger is the Tiger tank, a design which you would think was nearly invincible in combat from reading the modern hype of it, but in fact could be fairly easily seen off by 75mm armed Shermans, and occasionally killed by scout vehicles. Add to this chronic, never-solved reliability problems, outrageous production costs, and absurd maintenance demands (ten hours to change a single road wheel?), and you have a tank that really just wasn't very good. And so it is time to set the record straight on another historical design whose legend has outgrown its actual merit, the British EM-2: EM-2ology is a sadly under-developed field of study for gun nerds. There is no authoritative book on the history and design of this rifle. Yes, I am aware of the Collector's Grade book on the subject. I've actually read it and it isn't very good. It isn't very long, and it is quite poorly edited, among other sins devoting several pages to reproducing J.B.S. Haldane's essay On Being the Right Size in full. Why?!!?!! On top of that, there's quite a bit of misinformation that gets repeated as gospel. Hopefully, this thread can serve as a collection point for proper scholarship on this interesting, but bad design. Question One: Why do you say that the EM-2 was bad? Is it because you're an American, and you love trashing everything that comes out of Airstrip One? Why won't America love us? We gave you your language! PLEASE LOVE ME! I AM SO LONELY NOW THAT I TOLD THE ENTIRE REST OF EUROPE TO FUCK OFF. Answer: I'm saying the EM-2 was a bad design because it was a bad design. Same as British tanks, really. You lot design decent airplanes, but please leave the tanks, rifles and dentistry to the global superpower across the pond that owns you body and soul. Oh, and leave cars to the Japanese. To be honest, Americans can't do those right either. No, I'm not going to launch into some stupid tirade about how all bullpup assault rifle designs are inherently a poor idea. I would agree with the statement that all such designs have so far been poorly executed, but frankly, very few assault rifles that aren't the AR-15 or AK are worth a damn, so that's hardly surprising. In fact, the length savings that a bullpup design provides are very attractive provided that the designer takes the ergonomic challenges into consideration (and this the EM-2 designers did, with some unique solutions). Actually, there were two problems with the EM-2, and neither had anything to do with being a bullpup. The first problem is that it didn't fucking work, and the second problem is that there was absolutely no way the EM-2 could have been mass-produced without completely re-thinking the design. See this test record for exhaustive documentation of the fact that the EM-2 did not work. Points of note: -In less than ten thousand rounds the headspace of two of the EM-2s increased by .009 and .012 inches. That is an order of magnitude larger than what is usually considered safe tolerances for headspace. -The EM-2 was less reliable than an M1 Garand. Note that, contrary to popular assertion, the EM-2 was not particularly reliable in dust. It was just less unreliable in dust than the other two designs, and that all three were less reliable than an M1 Garand. -The EM-2 was shockingly inaccurate with the ammunition provided and shot 14 MOA at 100 yards. Seriously, look it up, that's what the test says. There are clapped-out AKs buried for years in the Laotian jungle that shoot better than that. -The EM-2 had more parts breakages than any other rifle tested. -The EM-2 had more parts than any other rifle tested. -The fact that the EM-2 had a high bolt carrier velocity and problems with light primer strikes in full auto suggests it was suffering from bolt carrier bounce. As for the gun being completely un-suited to mass production, watch this video: Question Two: But the EM-2 could have been developed into a good weapon system if the meanie-head Yanks hadn't insisted on the 7.62x51mm cartridge, which was too large and powerful for the EM-2 to handle! Anyone who repeats this one is ignorant of how bolt thrust works, and has done zero research on the EM-2. In other words, anyone who says this is stupid and should feel bad for being stupid. The maximum force exerted on the bolt of a firearm is the peak pressure multiplied by the interior area of the cartridge case. You know, like you'd expect given the dimensional identities of force, area and pressure, if you were the sort of person who could do basic dimensional analysis, i.e. not a stupid one. Later version of the British 7mm cartridge had the same case head diameter as the 7.62x51mm NATO, so converting the design to fire the larger ammunition was not only possible but was actually done. In fact, most the EM-2s made were in 7.62x51mm. It was even possible to chamber the EM-2 in .30-06. I'm not going to say that this was because the basic action was strong enough to handle the 7x43mm, and therefore also strong enough to handle the 7.62x51mm NATO, because the headspace problems encountered in the 1950 test show that it really wasn't up to snuff with the weaker ammunition. But I think it's fair to say that the EM-2 was roughly equally as capable of bashing itself to pieces in 7mm, 7.62 NATO or .30-06 flavor. Question Three: You're being mean and intentionally provocative. Didn't you say that there were some good things about the design? I did imply that there were some good aspects of the design, but I was lying. Actually, there's only one good idea in the entire design. But it's a really good idea, and I'm actually surprised that nobody has copied it. If you look at the patent, you can see that the magazine catch is extremely complicated. However, per the US Army test report the magazine and magazine catch design were robust and reliable. What makes the EM-2 special is how the bolt behaves during a reload. Like many rifles, the EM-2 has a tab on the magazine follower that pushes up the bolt catch in the receiver. This locks the bolt open after the last shot, which helps to inform the soldier that the rifle is empty. This part is nothing special; AR-15s, SKSs, FALs and many other rifles do this. What is special is what happens when a fresh magazine is inserted. There is an additional lever in each magazine that is pushed by the magazine follower when the follower is in the top position of the magazine. This lever will trip the bolt catch of the rifle provided that the follower is not in the top position; i.e. if the magazine has any ammunition in it. This means that the reload drill for an EM-2 is to fire the rifle until it is empty and the bolt locks back, then pull out the empty magazine, and put in a fresh one. That's it; no fussing with the charging handle, no hitting a bolt release. When the first magazine runs empty the bolt gets locked open, and as soon as a loaded one is inserted the bolt closes itself again. This is a very good solution to the problem of fast reloads in a bullpup (or any other firearm). It's so clever that I'm actually surprised that nobody has copied it. Question Four: But what about the intermediate cartridge the EM-2 fired? Doesn't that represent a lost opportunity vis a vis the too powerful 7.62 NATO? Sort of, but not really. The 7mm ammunition the EM-2 fired went through several iterations, becoming increasingly powerful. The earliest versions of the 7mm ammunition had similar ballistics to Soviet 7.62x39mm, while the last versions were only a hair less powerful than 7.62x51mm NATO. As for the 7mm ammunition having some optimum balance between weight, recoil and trajectory, I'm skeptical. The bullets the 7mm cartridges used were not particularly aerodynamic, so while they enjoyed good sectional density and (in the earlier stages) moderate recoil, it's not like they were getting everything they could have out of the design. note the flat base In addition, the .280 ammunition was miserably inaccurate. Check the US rifle tests; the .280 chambered proto-FAL couldn't hit anything either.
  16. 11 points
    Tied

    Tankograd T-62: Khruschev's bastard

    Source All Credit goes to: Mike Ennamoro and Tiles Murphy I highly recommend checking out there other articles, espically that on T-72 BLACK SHEEP Ask anybody politically savvy aged 50 and above and they will tell you that the unending string of proxy wars during the Cold War exuded a mostly artificial, but ever-present atmosphere of an imminent danger of a escalation into a full-blown nuclear world war. Fear and paranoia drove an age of accelerated technology growth predominantly concentrated in the military sector, producing various innovations which have crossed over into the non-military world. The proof is in our history textbooks today. The first rockets that sent satellites to space, for example, were modified ICBMs, and the Internet was originally a military project. New tanks sprang up like mushrooms after rain all over the world in approximately decadal increments, always to counter the last, always eclipsed by the next, but sometimes bordering on obsolescence from the moment they were created. One unfortunate example of the latter is the T-62. The T-62 is undeniably the least memorable among all of its world-famous post war era brothers - the T-54/55, T-64, T-72, T-80 and T-90 all come to mind - and it is also arguably the least historically significant among them all, but it was a step nonetheless in the evolutionary path to the modern T-14 we know today, and its relevance on the battlefield was certainly undeniable for the better part of two decades. The sentiment among the few amateur academic-enthusiasts that haven't forgotten the T-62's existence is that it was a highly mediocre design with a whopping gun, and in many ways, that is perfectly true from a technological standpoint in the evolution of armoured warfare during the Cold War. Between former Soviet tankers, however, the sentiment is slightly different. Many remember the T-62 fondly as a fairly reliable and endearing sweetheart that certainly had its own faults, but rarely ever disappointed - a sentiment echoed by Syrian and Iraqi tankers. The ones that lived, at least. Although woefully obsolete at present (it had already been totally purged from the Russian Armed Forces' inventories since 2013), it could at least boast of having the second most powerful tank cannon in the world for a few short years before being usurped by the T-64. Indeed, the sole reason of the T-62's existence was its pioneering smoothbore cannon. Tactically speaking, there were very few differences between it and its predecessor the T-54 in the mobility and armour protection departments, and the T-62 and the T-55, and indeed, both shared the same make of equipment to a large degree, thus simplifying both production and logistics. In fact, the technology of the T-62 was almost entirely derived from the T-55, and most of the interior instruments and controls are practically identical, making the transition from the T-54/55 to the T-62 wonderfully seamless. This degree of commonality wasn't entirely positive, though, because this meant that there was an unacceptable stagnation in armour technology - the type of stagnation seen on the American side of the Iron Curtain in their Patton series of tanks, which began service in the early 50's and dominated U.S Army tank units up til the early 80's. Had the designers decided to only continually modernize a T-54-type design like the Americans did with the Patton, then surely the Soviets would have never achieved the level of armoured superiority and technological excellence as they did in the late 60's, 70's and early 80's. The T-62 is an example of what Soviet tank armies could have been, but never was. It was flawed, redundant, unnecessary, and downright wasteful. But it was still valuable in its own little ways, and some of the technologies found in the T-62 even carried over to its successors. Many of its flaws (such as the U.S Army-propagated myth that it took 6 seconds to eject a spent shell casing) were in fact totally made up, but the tank was undeniably mediocre all the same. Tactically speaking, it had only a few advantages over its predecessor in the firepower department, but otherwise, the T-62 was nothing more than a more expensive T-55. It was plain to see that the T-62 was considered nothing more than a stopgap solution until the new and radically superior T-64 arrived on the scene, though it is some consolation that the T-62 was considered the most advanced Soviet main battle tank during its brief tenure. Being a mere evolutionary stepping stone, though, we can observe the way Soviet school of thought on mechanized warfare evolved with it. In the early 60's, tank riding infantry was still considered a core part of mechanized warfare. The armoured APC had arrived on the scene in the form of the wheeled BTR-152 and tracked BTR-50, but infantry were sometimes obliged to move and fight as one with a tank, and so to that end, the T-62 had handrails over the circumference of the turret for tank riders to hold on to. When the BMP-1 was introduced in 1966, it drove a major revision of contemporary tank tactics, and the shift in paradigm can be very well seen in the T-62's successors. The T-64 did not have any handrails, nor did the T-72, and the T-62M introduced in the late 60's abolished them too. The changes to the T-62 dutifully followed international trends too, most notably the global shift to jet power in the aviation industry. Too fast to be harmed by machine gun fire, the ground attack jet rendered the normally obligatory DShKM machine gun obsolete. The birth of the AH-1 Huey Cobra and the subsequent heavy use of helicopters for fire support and landing missions radically shifted the landscape, and the men and women at Uralvagonzavod obeyed. The DShKM was back by 1972. In the Soviet Union, the T-62 was produced from 1963 to 1975, with the first pre-production models appearing in 1961. After 1975, all "new" T-62s are actually simply upgraded, modified, or otherwise overhauled versions from the original production run. COMMANDER'S STATION The commander is seated on the port side of the turret, directly behind the gunner, and to his left is the R-113 radio station, created just as the T-62 first entered service in 1961. ' The R-113 radio operates in the 20.00 to 22.375 MHz range and has a range of 10 to 20 km with its 4 m-long antenna. It could be tuned into 96 frequencies within the limits of its frequency range. In 1965, the radio was swapped out for a newer and much more advanced R-123 radio. The R-123 radio had a frequency range of between 20 MHZ to 51.5 MHZ. It could be tuned to any frequency within those limits via a knob, or the commander could instantly switch between four preset frequencies for communications within a platoon. It had a range of between 16km to 50km. The R-123 had a novel, but rather redundant frosted glass prism window at the top of the apparatus that displayed the operating frequency. An internal bulb illuminated a dial, imposing it onto the prism where it is displayed. The R-123 had an advanced modular design that enabled it to be repaired quickly by simply swapping out individual modules. It is quite clear that the commander's station is the most habitable one by far in the very spartan T-62. The close proximity between all the turret occupants with each other and the shortage of breathing space makes the internal climate hot and humid, contributing to the overall discomfort. This is compounded by the fact that the crew isn't provided with any local ventilators such as fans or directed air vents, so it can get quite stuffy inside. However, the commander seems to be the most well off, since he sits right in front of the sole ventilator in the turret and he isn't required to exert himself physically, unlike the loader. Unique to the rest of the dome-shaped turret, the area around his station was cast to be devoid of any vertical sloping or rounding whatsoever, which was necessary to enable his rotating cupola to be installed. This meant that the debilitating effects of the ostensibly dome-shaped turret are completely lost on him. The cupola is mounted on a race ring. The fixed part constitutes half of the total size of the cupola, while the other half is occupied by the semicircular hatch, which has a maximum width of 590mm. The hatch opens forward, which is quite convenient for when the commander wants to survey the landscape from outside - perhaps with a pair binoculars - because being as thick as it is, the hatch is a superb bulletproof shield for protecting the commander from sniper fire. There is also a small porthole in the hatch. It is meant for an panoramic periscope tube for indirect fire. As befitting his tactical role, the commander's general visibility is facilitated by two TNPO-170 periscopes on either side of the primary surveillance periscope in the fixed forward half of the cupola, and further augmented by two more 54-36-318-R periscopes embedded in the hatch, aimed to either side for additional situational awareness. Overall, this scheme was sufficient for most purposes, but was deficient if compared to the much more generous allowance of periscopes and vision ports found on NATO tanks. The TNPO-170 periscope has a total range of vision of 94° in the horizontal plane and 23° in the vertical plane. The four periscopes in addition to the TKN-type periscope aimed directly forward gives the commander a somewhat acceptable field of vision over the turret's front arc. The use of periscopes instead of direct glass vision blocks presents pros and cons - for one, the lack of any direct vision means that the viewer's eyes is protected from machine gun fire or glass specks if the device is destroyed, but a bank of periscopes offer a much more limited panorama than vision blocks like the type found in the commander's cupola on the M60 tank. TKN-2 "Karmin" The original 1961 model of the T-62 featured the TKN-2 binocular periscopic surveillance device (above) mounted in the rotating cupola. It had a fixed x5 magnification in the day mode, with an angular field of view of 10°, allowing a nominal maximum detection range of a tank-sized target at approximately 3 km, though this was greatly dependent on geography as well as weather conditions. The periscope could be manipulated up by +10° and down by -5°, while the cupola would have to be turned for horizontal surveillance. The TKN-2 had an active night channel which picked up infrared light from the OU-3 IR spotlight attached to the periscope aperture to provide a limited degree of night vision to the commander. With a nominal viewing range of only about 300 to 400 m, the TKN-2 was all but useless for serious target acquisition at night, serving only to give away the tank's position the moment the spotlight was turned on. Performance could be improved with mortar-delivered IR flares, of course, but that doesn't count as an intrinsic merit of the device itself. Due to the fact that the periscope is unstabilized, identifying another tank at a distance is very difficult while on the move over very rough terrain. However, the commander is meant to bear down and brace against the handles of the periscope for improvised stabilization, which is adequate for when driving over a dirt road, but not when traversing over especially rough terrain. The periscope's small elevation allowance was for this purpose. The left handle has a thumb button for turning the OU-3 spotlight on or off. The OU-3 is a high-powered xenon arc lamp with an IR filter to create only infrared light. The filter isn't opaque, though, and the spotlight will glow faintly red. It is mechanically linked to the periscope, enabling it to elevate with the TKN-2. ^OU-3 IR spotlight with the IR filter removed to transform it into a regular white light spotlight^ TKN-3 "Kristal" In 1964, the revised T-62 was instead equipped with the TKN-3 pseudo-binocular combined periscope, which is a direct descendant of the TKN-2. Pseudo-binocular meaning that although the device has two eyepieces, the two optic tubes are combined to feed from one aperture, which the viewer sees out of. It has a fixed 5x magnification in the day channel with an angular field of view of 10°, and a fixed 3x magnification in the night channel with an angular field of view of 8°. The periscope can be manipulated up and down for elevation, and the commander's cupola must be turned for horizontal viewing. The TKN-3 was a sufficiently modern observation device of its time. It featured target cuing, was very compact, and had a relatively advanced passive light intensification system, but it wasn't stabilised, and featured only rudimentary rangefinding capabilities as a cost saving measure. It offered rudimentary night vision capability in two flavours; passive light intensification or active infrared. In the passive mode of operation, the TKN-3 intensifies ambient light to produce a more legible image. This mode is useful down to ambient lighting conditions of at least 0.005 lux, which would be equivalent to an overcast, moonless and starless night. In these conditions, the TKN-3 can be used to identify a tank-type target at a nominal distance of 400m, but as the amount of ambient light increases such as on starlit or moonlit nights, the distance at which a tank-sized target is discernible can be extended to up to 800m in dark twilight hours. Any brighter, though, and the image will be oversaturated and unintelligible. The active mode requires the use of the OU-3K IR spotlight, which is practically identical to the OU-3 performance-wise. With active infrared imaging, the commander can identify a tank at 800m, or potentially more if the opposing side is also using IR spotlights, in which case, the TKN-3 can be set to the active mode but without turning on the IR spotlight. Rangefinding is accomplished through the use of a stadiametric scale sighted for a target with a height of 2.7 m, which is the average size of the average NATO tank. Like the TKN-2, the TKN-3 is unstabilized, making it exceedingly difficult to reliably identify enemy tanks or other vehicles at extended distances while the tank is travelling over rough terrain, let alone determine the range. The left thumb button initiated turret traverse for target cuing, and the right thumb button turned the OU-3K spotlight on or off. The range of elevation is +10° to -5°, just like the TKN-2. The OU-3K spotlight is also directly mechanically linked to the periscope (the arm to which the spotlight is linked to can be seen in the photo above) to enable it to elevate with the TKN-3. Target cuing is done by placing the crosshair reticle in the periscope's viewfinder over the intended target and pressing the cue button. The system only accounts for the cupola's orientation, though, and not the periscope's elevation, so the cannon will not elevate to meet the target; only the turret will. Because the cupola did not was not counter rotated as turret traverse was initiated, it will be spun along with the turret as it rotates to meet the target cued by the commander, potentially causing him to lose his bearings. To prevent this, there is a simple U-shaped steel rung for him to brace with his right arm as he uses his left hand to designate the target. This wasn't as convenient as a counter rotating motor, of course, but it was better than nothing. Ventilation for the crew is facilitated by the KUV-3 ventilator, identifiable on the rear of the turret as a large, overturned frying pan-shaped tumor on the rear of the turret. A centrifugal fan inside the ventilator housing sucks in air and performs some low level filtration, ejecting dust and larger particles out of a small slit at the base of the housing (refer to photo above), and then released into the crew compartment, passing through a drum-shaped NBC filter unit inside the tank proper. The air can be optionally cleaned of chemical and biological contaminants by the filter in contaminated environments where the centrifugal fan is simply not enough. The filter unit also contains a supercharger to increase the positive pressure inside the tank to produce an overpressure, preventing chemical and biological agents from seeping into the tank. Notice the PVC pipe connecting it to the ventilation dome on the outside of the turret rear But being the commander is still a mixed blessing, because his seat is seated right in front of the hydraulic pump, subjecting him to more acoustic fatigue than anyone else in the tank (the green canister is the hydraulic pump). Nevertheless, the commander's station is the second most roomy one in the tank, besides the loader's station. Here in the photo below, you can see his seat back and the few pieces of equipment that he is responsible for. Sometime during the 70's, a select few T-62s received a shield of sorts over the commander's hatch. It is a sheet steel face shield with a canvas skirt draping down. Being so thin, the face shield is not bulletproof, though perhaps resistant to hand grenade fragments and small mortar splinters. Since it doesn't really do very well as ballistic protection, the main function of the shield appears to be to conceal the opening of the commander's hatch to disguise his exit from the prying eyes of snipers, and to keep away dust if the commander feels like sitting outside during road marches. Either way, not many T-62s received the addition, though almost all T-72s did. The reason for the bias is unknown. GUNNER'S STATION The gunner is squeezed into his corner of the turret, wedged between the turret wall to the left and the cannon breech to the right, and between the commander and the sights. It is so cramped that the commander must partially wrap his knees around him. As was, and still is common among manually loaded tanks, the gunner doesn't have a hatch of his own. Instead, he must ingress and egress through the commander's hatch. The biggest flaw with this layout is that if the commander is unconscious, incapacitated or killed, then the gunner will suddenly find it extremely difficult to leave the tank unless the commander was somehow completely vaporized. Even worse, if the tank has been struck, there is a very distinct possibility that the interior is catching fire. Plus, another flaw with the layout is if the turret was perforated through the front on the port side cheek, both the gunner and commander would be killed, effectively rendering the tank useless in combat. For extra visibility, the gunner has a single TNP-165 periscope pointed forward and slightly to the right, though for what exact purpose this lone periscope is meant for is unknown, since the field of view from it is so small that the gunner can't really see very much, nor can the commander seated behind him. It is more useful for the commander for checking directly in front of the tank. In addition to all of the necessary switches and toggle buttons to activate this and that, there are also some other odds and ends at his station, including a turret azimuth indicator, which is used to orient the turret for indirect fire. It is akin to a clock, having two hands - one for general indication measured in degrees, and the other in 100 mil increments for precise turret traverse. SIGHTING COMPLEX TSh2B-41 sight aperture port, with nuclear attack seal in place The gunner is provided with either a monocular TSh2B-41 or a TSh2B-41U (in later models) primary sight and a TPN-1-41-11 night sight, which also functions as a backup sight in the event of the failure or destruction of the primary sight. TSh2B-41 The TSh2B-41 is a monocular telescopic sight, functioning as the gunner's primary sight for direct fire purposes. It has two magnification settings, x3.5 or x7, and an angular field of view of 18° in the former setting and 9° in the latter setting. As was and still is common for all tank sights, it has an anti-glare coating for easier aiming when facing the sun. It comes with a small wiper to clean it from moisture, and it comes with an integrated heater for defrosting. Like most other tanks of its time, the T-62 lacked a ballistic computer, but it was also unusually deficient in the rangefinding department. For rangefinding, the gunner had to make use of a stadiametric ranging scale embossed on the sight aperture. Compared to optical coincidence rangefinders, stadia rangefinding was terribly imprecise, but also much simpler in both production and employment, and much more economical than, say, optical coincidence rangefinding. In fact, stadia rangefinding is essentially free, since all that is needed are some etchings into the sight lens. The savings made from the exclusion of an optical coincidence rangefinder were enormous, amounting to many thousands of rubles. Ranging errors of up to several hundred meters is often the norm, especially if some of the lower part of the target vehicle is obscured behind vegetation or other terrain features. It isn't uncommon for the first shot on faraway tank-sized targets to fall woefully short or fly clear over. Below is the sight picture: From left to right: APFSDS, HEAT, HE-Frag, Co-Axial Machine Gun When the gunner has obtained range data, he manually enters the necessary correction into the sighting system by turning a dial. The dial adjusts the sight to calibrate it for that range. Calibration is when the chevron is elevated or depressed to account for range. If the target is very far away, for example, then the chevron will be dropped significantly, forcing the gunner to sharply elevate the gun to line up the target with the chevron, thus forming a ballistic solution. Because APFSDS, HEAT and HE-Frag shells all have different ballistic characteristics, the gunner must refer to a set of fixed range scales drawn on the upper half of the sight in order to get the proper gun elevation. For instance, if the target is 1.6 km away, and the gunner wishes to engage it with high explosive shells, then he must line up a horizontal bar (which moves up and down with the targeting chevron but at different speeds due to a reduction gear) with a notch on the range scale for "OF" shells that says "16". If the gunner wishes to use APFSDS instead, then he need only line up the horizontal bar with the "16" notch on the "BR" scale. Then, the chevron will show how much supraelevation is needed in order to hit the target with the selected ammunition. The gunner will then lay the chevron on the target and open fire. The sight has an internal light bulb that when turned on, illuminates the reticle for easier aiming in poor lighting conditions such as during twilight hours or dawn. Unless the gunner had 20/20 vision and the tank was completely still, considerable ranging errors in the neighborhood of 100 or so meters was the norm, and as the distance from the target increased, the accuracy of the measurement decreased exponentially, deteriorating drastically past 2000 m. As such, it is more difficult hitting targets with lower velocity ammunition like HE-Frag and HEAT shells, and even harder for moving targets. However, the inclusion of near-hypersonic APFSDS ammunition in the T-62's loadout greatly helped counterbalance this issue, making it markedly easier for the gunner to hit both stationary and moving tank-type targets, while most targets requiring HE-Frag shells like machine gun nests and pillboxes and other fortifications would be stationary anyway, thus making pinpoint accuracy much less of a priority. Even so, on account of the extremely high speed of the APFSDS rounds fired from the 2A20 gun, the sight can be battlesighted at a very generous 1000 m, allowing the gunner to confidently hit a tank of NATO-type dimensions at any distance between 200 to 1600 m by aiming at center mass without needing to ascertain the range beforehand. However, one inescapable flaw of the TSh2B-41U was that it lacked independent vertical stabilization, being directly mechanically linked to the 2A20 cannon, forcing it to elevate with it when the loading procedure is underway. This causes the gunner to (very annoyingly) lose sight of anything he is aiming at at the moment, making the commander's the only pair of eyes to observe the 'splash' and give corrections or search for new targets. This led to the development of the independently stabilized TSh2B-41U.
  17. 11 points
    Beer

    Czechoslovak interwar bits

    Hello guys, I think that possibly some of you might be interested in our interwar Czechoslovak stuff. For starter I've decided to share with you a wonderful online document about our fortification system. At the very beginning I'd like to say that I have nothing common with its creators. It's just an incredible gem that deserves to be shared with you. If you know it, sorry for that, nevertheless I think most of you don't. Since I am new here I will not waste your time debating what if scenarios. Don't worry. Well, enough of talking. What I want to share with you is a massive interactive map of our fortification system containing nearly 11 thousand objects with information about every single one of them. You can switch on even such crazy details like cable networks or construction facilities used for building of the fortifications. The map is directly linked with an online database of the fortification buildings where more than 2000 objects are listed with detailed description (plans, 3D models, photos, weapons, crew, important dates, recent state etc.). Unfortunately this database is only in Czech language but it can be a great source of information for you anyway (especially when linked with the map). The good thing is that the map alone supports other languages and you can easily switch them. This is the base view where I have already switched on all objects. You can change background map type, information etc. on the left side and visualise everything what You want to see on the right side. Let's zoom in a little bit. Here You can see one of the strongest fortified places - a valey at Králíky in north-east Czechia. As you can see the object marks have different shapes, colours etc. The shape is matching the menu on the right side. Triangles are concrete pillboxes vz. (mark) 36. Small circles are pillboxes vz. 37. The letter inside means type of the object (with one firing post, two on each side, angled one etc.). The color can be decoded from the information table in the bottom right corner. Basically it shows whether the object was actually built, if it was later destroyed or the works were only started or even not so. The heavy objects are the large circles. The numbers have also a meaning. It's a resistance class (1 -> 2 -> I -> IV from the lowest to the most resistant). You can switch on also the ground plans of the artilery groups (fortresses with underground network between the casemates). You can see it here (fortress Hůrka). You can also switch on the firing lines. Here You can see heavy artilery coverage of the most fortified section of the line (the sad thing is that no heavy artilery pieces were installed by the time of Münich crisis - but lets leave such details aside for now). You can switch on the firing lines even for the pillboxes as you can see here on the example from the souther border. Nearly all Czechoslovak objects were built for side fire having superheavy resistance frontal walls with stone and earth covers. If You zoom even more and switch for satelite map you get something like this. In this case the red color shows anti tank 47 mm guns and the blue color is 7,92 mm (sometimes double) heavy machine guns of a heavy separated casemate (possible use of light machine guns in observation cupolas is not marked). The grey color shows vz.26 light machine guns of the neighbouring pillbox. You can click on every single object and you get available details. The first icon shows detailed lines of fire including realistic range. Bellow the L: L1 M ZN 3-4 means: Left side: L1 = 47 mm anti tank gun with 7,92 mm coaxial heavy MG; M = twin 7,92 heavy MG; ZN is I think type of the cupola but I'm not actually sure about it. The codes for the weapons are shown at the table in the lower right corner (you need to keep the cursor on the question mark). The Second icon leads to a database of objects which is unfortunately only in our weird language. Anyway you can dig a lot of information from it as well (drawings, recent state, photos, exact location etc.). The best thing is that most of the objects still exist till today (all of those heavy ones). The Germans managed to destroy roughly 2000 light objects (and gain some 11000 tons of steels from them). They managed to damage also many heavy ones when they were testing weapons and tactics for the future use duirng the WW2. They even moved some cupolas (and of course the famous hedgehogs) to other fortifications along the Atlantic wall or elsewhere. Many of them are made into better or worse museums today (large quantity is private now). Huge number of them is just left alone and freely accessible for anyone. If you are more interested I can give you tips which ones to visit. On the Czech map portal You can use a mode panorama which is basically the same thing as Google street view but it's much more up to date and it's nearly everywhere where they got at least with a motorbike. Since the fortifications are also visible there, you check where they are for easier access. If you are interested I can continue the fortification topic with some other information (I'm no historian but I have visited quite many of the objects myself and read some books about them). OK, so this was my first post on the forum. I hope you find it interesting and maybe for some of you it can be a reason for a trip, who knows :-)
  18. 11 points
    What a Long, Strange Trip it's Been PC gaming has been a hell of a ride. I say "has been" both in the sense that exciting and dynamic things have happened, but also in the sense that the most exciting and dynamic times are behind us. No other form of video gaming is as closely tied to the latest developments in personal computing hardware, and current trends do not suggest that anything dramatically new and exciting is immediately around the corner. Indeed, fundamental aspects of semiconductor physics suggest that chip technology is nearing, or perhaps already on a plateau where only slow, incremental improvement is possible. This, in turn, will limit the amount of improvement possible for game developers. Gaming certainly will not disappear, and PC gaming will also not disappear, although the PC gaming share of the market may contract in the future. But I think it is a reasonable expectation that future PC game titles will not be such dramatic technological improvements over older titles as was the case in the past in the near term. In the long term, current technology and hardware design will eventually be replaced with something entirely different and disruptive, but as always it is difficult, maybe impossible to predict what that replacement will be. The Good Old Days The start of the modern, hardware-driven PC gaming culture that we all know and love began with Id Software's early first person shooter titles, most importantly 1993's Doom. PC gaming was around before Doom, of course, but Doom's combination of cutting edge graphics technology and massive, massive appeal is what really got the ball rolling. Doom was phenomenally popular. There were, at one point, more installs of Doom than there were installs of the Windows operating system. I don't think there is any subsequent PC title that can claim that. Furthermore, it was Doom, and its spiritual successor Quake that really defined PC gaming as a genre that pushed the boundaries of what was possible with hardware. Doom convincingly faked 3D graphics on computers that had approximately the same number-crunching might as a potato. It also demanded radically more computing power than Wolfenstein 3D, but in those days computing hardware was advancing at such a rate that this wasn't really unreasonable. This was followed by Quake, which was actually 3D, and demanded so much more of the hardware then available that it quickly became one of the first games to support hardware acceleration. Id software disintegrated under the stress of the development of Quake, and while many of the original Id team have gone on to do noteworthy things in PC gaming technology, none of it has been earth-shaking the way their work at Id was. And so, the next important development occurred not with Id's games, but with their successors. It had become clear, by that point, that there was a strong consumer demand for higher game framerates, but also for better-looking graphics. In addition to ever-more sophisticated game engines and higher poly-count game models, the next big advance in PC gaming technology was the addition of shaders to the graphics. Shaders could be used to smooth out the low-poly models of the time, apply lighting effects, and generally make the games look less like spiky ass. But the important caveat about shaders, from a hardware development perspective, was that shader code ran extremely well in parallel while the rest of the game code ran well in series. The sort of chip that would quickly do the calculations for the main game, and the sort of chip that would do quickly do calculations for the graphics were therefore very different. Companies devoted exclusively to making graphics-crunching chips emerged (of these, only Nvidia is left standing), and the stage was set for the heyday of PC gaming hardware evolution from the mid 1990s to the early 2000s. Initially, there were a great number of hardware acceleration options, and getting everything to work was a bit of an inconsistent mess that only enthusiasts really bothered with, but things rapidly settled down to where we are today. The important rules of thumb which have, hitherto applied are: -The IBM-compatible personal computer is the chosen mount of the Glorious PC Gaming Master Race™. -The two most important pieces of hardware on a gaming PC are the CPU and the GPU, and every year the top of the line CPUs and GPUs will be a little faster than before. -Even though, as of the mid 2000s, both gaming consoles and Macs were made of predominantly IBM-compatible hardware, they are not suitable devices for the Glorious PC Gaming Master Race™. This is because they have artificially-imposed software restrictions that keep them from easily being used the same way as a proper gaming PC. -Even though they did not suffer from the same compatibility issues as consoles or Macs, computers with integrated graphics processors are not suitable devices for the Glorious PC Gaming Master Race™. -Intel CPUs are the best, and Nvidia GPUs are the best. AMD is a budget option in both categories. The Victorious March of Moore's Law Moore's Law, which is not an actual physical law, but rather an observation about the shrinkage of the physical size of transistors, has held so true for most of the 21st century that it seemed like it was an actual fundamental law of the universe. The most visible and obvious indication of the continuous improvement in computer hardware was that every year the clock speeds on CPUs got higher. Now, clock speed itself isn't actually particularly indicative of overall CPU performance, since that is a complex interplay of clock speed, instructions per cycle and pipe length. But at the time, CPU architecture was staying more or less the same, so the increase in CPU clock speeds was a reasonable enough, and very marketing-friendly indicator of how swimmingly things were going. In 2000, Intel was confident that 10 GHZ chips were about a decade away. This reliable increase in computing power corresponded with a reliable improvement in game graphics and design year on year. You can usually look at a game from the 2000s and guess, to within a few years, when it came out because the graphical improvements were that consistent year after year. The improvement was also rapid. Compare 2004's Far Cry to 2007's Crysis. And so, for a time, game designers and hardware designers marched hand in hand towards ever greater performance. The End of the Low-Hanging Fruit But you know how this works, right? Everyone has seen VH1's Behind the Music. This next part is where it all comes apart after the explosive success and drugs and groupies, leaving just the drugs. This next part is where we are right now. If you look again at the chart of CPU clock speeds, you see that improvement flatlines at about 2005. This is due to the end of Dennard Scaling. Until about 2006, reductions in the size of transistors allowed chip engineers to increase clock speeds without worrying about thermal issues, but that isn't the case anymore. Transistors have become so small that significant amounts of current leakage occur, meaning that clock speeds cannot improve without imposing unrealistic thermal loads on the chips. Clock speed isn't everything. The actual muscle of a CPU is a function of several things; the pipeline, the instructions per clock cycle, clock speed, and, after 2005 with the introduction of the Athlon 64X2, the core count. And, even as clock speed remained the same, these other important metrics did continue to see improvement: The catch is that the raw performance of a CPU is, roughly speaking, a multiplicative product of all of these things working together. If the chip designers can manage a 20% increase in IPC and a 20% increase in clock speed, and some enhancements to pipeline design that amount to a 5% improvement, then they're looking at a 51.2% overall improvement in chip performance. Roughly. But if they stop being able to improve one of these factors, then to achieve the same increases in performance, they need to cram in the improvements into just the remaining areas, which is a lot harder than making modest improvements across the board. Multi-core CPUs arrived to market at around the same time that clock speed increases became impossible. Adding more cores to the CPU did initially allow for some multiplicative improvements in chip performance, which did buy time for the trend of ever-increasing performance. The theoretical FLOPS (floating point operations per second) of a chip is a function of its IPC, core count and clock speed. However, the real-world performance increase provided by multi-core processing is highly dependent on the degree to which the task can be paralleled, and is subject to Amdahl's Law: Most games can be only poorly parallelized. The parallel portion is probably around the 50% mark for everything except graphics, which has can be parallelized excellently. This means that as soon as CPUs hit 16 cores, there was basically no additional improvement to be had in games from multi-core technology. That is, unless game designers start to code games specifically for better multi-core performance, but so far this has not happened. On top of this, adding more cores to a CPU usually imposes a small reduction to clock speed, so the actual point of diminishing returns may occur at a slightly lower core count. On top of all that, designing new and smaller chip architecture has become harder and harder. Intel first announced 10nm chip architecture back in September 2017, and showed a timeline with it straddling 2017 and 2018. 2018 has come and gone, and still no 10nm. Currently Intel is hopeful that they can get 10nm chips to market by the end of 2019. AMD have had a somewhat easier time of it, announcing a radically different mixed 14nm and 7nm "chiplet" architecture at the end of 2018, and actually brought a 7nm discrete graphics card to market at the beginning of 2019. However, this new graphics card merely matches NVIDIA's top-of-the-line cards, both in terms of performance and in terms of price. This is a significant development, since AMD's graphics cards have usually been second-best, or cost-effective mid-range models at best, so for them to have a competitive top-of-the-line model is noteworthy. But, while CPUs and GPUs are different, it certainly doesn't paint a picture of obvious and overwhelming superiority for the new 7nm process. The release of AMD's "chiplet" Zen 2 CPUs appears to have been delayed to the middle of 2019, so I suppose we'll find out then. Additionally, it appears that the next-generation of Playstation will use a version of AMD's upcoming "Navi" GPU, as well as a Zen CPU, and AMD hardware will power the next-generation XBOX as well. So AMD is doing quite well servicing the console gaming peasant crowd, at least. Time will tell whether the unexpected delays faced by their rivals along with the unexpected boost from crypto miners buying literally every fucking GPU known to man will allow them to dominate the hardware market going forward. Investors seem optimistic, however: With Intel, they seem less sanguine: and with NVIDIA, well... But the bottom line is don't expect miracles. While it would be enormously satisfying to see Intel and NVIDIA taken down a peg after years of anti-consumer bullshit, the reality is that hardware improvements have fundamentally become difficult. For the time being, nobody is going to be throwing out their old computers just because they've gotten slow. As the rate of improvements dwindles, people will start throwing out their old PCs and replacing them only because they've gotten broken. OK, but What About GPUs? GPU improvements took longer to slow down than CPU improvements, in large part because GPU workloads can be parallel processed well. But the slowdown has arrived. This hasn't stopped the manufacturers of discrete GPUs from trying to innovate, of course. Not only that; the market is about to become more competitive with Intel announcing their plans for a discrete GPU in the near future. NVIDIA has pushed their new ray-tracing optimized graphics cards for the past few months as well. The cryptomining GPU boom has come and gone; GPUs turn out to be better than CPUs at cryptomining, but ASICs beat out GPUs but a lot, so that market is unlikely to be a factor again. GPUs are still relatively cost-competitive for a variety of machine learning tasks, although long-term these will probably be displaced by custom designed chips like the ones Google is mass-ordering. Things really do not look rosy for GPU sales. Every time someone discovers some clever alternative use for GPUs like cryptomining or machine learning, they get displaced after a few years by custom hardware solutions even more fine-tuned to the task. Highly parallel chips are the future, but there's no reason to think that those highly parallel chips will be traditional GPUs, per se. And speaking of which, aren't CPUs getting more parallel, with their ever-increasing core count? And doesn't AMD's "chiplet" architecture allow wildly differently optimized cores to be stitched together? So, the CPU of a computer could very easily be made to accommodate capable on-board graphics muscle. So... why do we even need GPUs in the future? After all, PCs used to have discrete sound cards and networking cards, and the CPU does all of that now. The GPU has really been the last hold-out, and will likely be swallowed by the CPU, at least on low and mid range machines in the next few years. Where to Next? At the end of 2018, popular YouTube tech channel LinusTechTips released a video about Shadow. Shadow is a company that is planning to use centrally-located servers to provide cloud-based games streaming. At the time, the video was received with (understandably) a lot of skepticism, and even Linus doesn't sound all that convinced by Shadow's claims. The technical problems with such a system seem daunting, especially with respect to latency. This really did seem like an idea that would come and go. This is not its time; the technology simply isn't good enough. And then, just ten days ago, Google announced that they had exactly the same idea: The fact that tech colossus Google is interested changed a lot of people's minds about the idea of cloud gaming. Is this the way forward? I am unconvinced. The latency problems do seem legitimately difficult to overcome, even for Google. Also, almost everything that Google tries to do that isn't search on Android fails miserably. Remember Google Glass? Google Plus? But I do think that games that are partially cloud-based will have some market share. Actually, they already do. I spent a hell of a lot of time playing World of Tanks, and that game calculates all line-of-sight checks and all gunfire server-side. Most online games do have some things that are calculated server-side, but WoT was an extreme example for the time. I could easily see future games offloading a greater amount of the computational load to centralized servers vis a vis the player's own PC. But there are two far greater harbingers of doom for PC gaming than cloud computing. The first is smart phones and the second is shitty American corporate culture. Smart phones are set to saturate the world in a way desktop PCs never did. American games publishers are currently more interested in the profits from gambling-esque game monetization schemes than they are in making games. Obviously, I don't mean that in a generic anti-capitalist, corporation-bashing hippie way. I hate hippies. I fuck hippies for breakfast. But if you look at even mainstream news outlets on Electronic Arts, it's pretty obvious that the AAA games industry, which had hitherto been part of the engine driving the games/hardware train forward, is badly sick right now. The only thing that may stop their current sleaziness is government intervention. So, that brings us to the least important, but most discussion-sparking part of the article; my predictions. In the next few years, I predict that the most popular game titles will be things like Fortnite or Apex Legends. They will be monetized on some sort of games-as-service model, and will lean heavily if not entirely on multiplayer modes. They may incorporate some use of server-side calculation to offload the player PC, but in general they will work on modest PCs because they will only aspire to have decent, readable graphics rather than really pretty ones. The typical "gaming rig" for this type of game will be a modest and inexpensive desktop or laptop running built-in graphics with no discrete graphics card. There will continue to be an enthusiast market for games that push the limits, but this market will no longer drive the majority of gaming hardware sales. If these predictions sound suspiciously similar to those espoused by the Coreteks tech channel, that's because I watched a hell of a lot of his stuff when researching this post, and I find his views generally convincing. Intel's Foveros 3D chip architecture could bring a surge in CPU performance, but I predict that it will be a one-time surge, followed by the return to relatively slow improvement. The reason why is that the Foveros architecture allows for truly massive CPU caches, and these could be used to create enormous IPC gains. But after the initial boon caused by the change in architecture, the same problems that are currently slowing down improvement would be back, the same as before. It definitely wouldn't be a return to the good old days of Moore's Law. Even further down the road, a switch to a different semiconducting material such as Gallium Nitride (which is already used in some wireless devices and military electronics) could allow further miniaturization and speed ups where silicon has stalled out. But those sort of predictions stretch my limited prescience and knowledge of semiconductor physics too far. If you are interested in this stuff, I recommend diving into Coretek's channel (linked above) as well as Adored TV.
  19. 11 points
    I'm sure that all the SH regulars will know this backwards and forwards, so this is more for the benefit of newer people, or people who stumble in via google, or people who want a quick link they can throw out as an answer to anyone who asks the question. So, what's with the goofy-ass road wheel design on German WWII AFVs? A puzzled and terrified worker struggles to comprehend and assemble the suspension of a tiger I You may have run into a variety of explanations for this running gear design; that it provided a smoother ride, that the design saved rubber, or possibly some other rubbish. Like the myth that frontal drive sprockets provide more traction (seriously, how in the hell is that supposed to make any sense?), these wrong explanations of the merits of interleaved road wheels seem to rise from some quote taken out of context. The interleaved road wheel running gear may have saved some rubber relative to an alternative design that was particularly wasteful of it. But interleaved road wheels are not particularly economic in this respect because, and I realize this is a complicated concept to explain so I'll try my best, they have more wheels. Interleaved road wheels do allow for large wheel diameters, and a larger diameter wheel will spread wear out over a larger circumference. So interleaved road wheels might allow for the rubber on the wheels to last longer, although their construction would require more in the first place. Interleaved road wheels would not improve ride quality either. The ride quality of a tank is not a function of the size or number of wheels it possesses, but of how they are sprung. So, it is possible that in certain competitive trials an interleaved road wheel design outperformed a design that lacked this feature. I could readily believe, for instance, that the tiger (H) had a better ride quality on rough terrain than the tiger (P), or that the SDKFZ. 251 had a smoother ride than the M3. However, this would be because the tiger (H) and SDKFZ. 251 have independently sprung road wheels on torsion bars while the tiger (P) and M3 do not. Torsion bar layout of the tiger II Volute spring suspension of the M3 half track So, what do interleaved road wheels do? They have two principal effects; one is a small benefit, and the other is an enormous detriment. The small benefit of interleaved road wheels is that they spread the weight of the vehicle out more evenly on the track links: The weight of a tank is not completely evenly spread out on the contact area of its tracks. This is because tracks are not rigid. If they were, they would be mainly ornamental and tanks' engines would just be for show. More of the weight of a tank is concentrated under the parts of the track that the road wheels are sitting directly on top of. Additionally, once a tank starts to sink into the soil a bit, larger road wheels work better than smaller ones because the larger ones have more contact area. But you can only fit so many large diameter road wheels in the space of a tank's hull. Dynamic! So, the only way to have lots of road wheels and have big road wheels at the same time is to interleave them. Simple as that. If you would like an exhaustive look at the development of the semi-empirical MMP equation, read this. The major, crippling downside to interleaved road wheels is that it makes changing the road wheels extremely time consuming. A pair of workers perform maintenance on a panther tank, and contemplate the futility of all human achievement Lucas Friedli reprints in his book on big cat maintenance a report from a training unit complaining that replacing the inner road wheels of a tiger tank took ten hours. That is completely outrageous, and was a contributor to the poor operational availability of the big cats. For this reason, interleaved road wheels have rarely been used after World War Two; only on a few French prototypes and a Swedish APC: PBV 302 variant with interleaved road wheels Some bizarre French tank
  20. 11 points
  21. 11 points
    About two and a half years ago i've stumbled across some russian book about western IFVs, which apparently was a mere compilation of articles from western magazines translated into russian. There was a mention of some 58-ton heavy IFV, called SAIFV, which was described as vehicle baised on Abrams chassis, and they also claimed that a prototype was biult and tested. (which seems dubious to me now) Than, two years ago, I've stumbled across this article about SAIFV https://medium.com/war-is-boring/the-u-s-army-wanted-to-replace-the-bradley-38-years-ago-dffb6728dd11 which has 3 drawings - "artist conceptions". Than, half a year ago I was reading some US DOD bidget hearings transcripts about MICV/IFV development, and stumbled across mentions of 50-55 metric tons $800,0000 - 1,000,000 SAIFV of Crizer study, and than I've googled a Mobility analysis of IFV task force alternatives (1978-07) report (which is allmost the same as Appendix D of that report which is described below). Unfortunatelly there weren't any proper pictures, (and also i've thought that those 3 drawings from medium.com article are modern "artist conceptions", not one from 1978). Than several things happend in the right time and place, which invlolved twitter, AUSA-2018, NGCV-OMFV, and author of that arcticle at medium.com, and when I asked him about that article - it turned out that there is a report about SAIFV, which is readily available on the internet there http://cdm16635.contentdm.oclc.org/cdm/singleitem/collection/p16635coll14/id/56079/rec/1 884 pages, with 7 normal chapters and chapter 8 which consists of 6 appendices. cost figures from Appendices F and B: things like those cost figures, coupled with deceiving percents like this (Ch. IV p.17): (there were also other versions mentioned in Senate hearings of FY1978-1980s - 91.6%, 92%, 95%, and also they've mentioned soviet motorized rifle division instead of tank regiment) apparently saved Bradley. Although in 1979 those $370,000 turned out to be $472,000 (in same FY1978 dollars), - and later according to FY1983 bidget hearings - $1,350,000 (which is about $880,000 in 1978 dollars). ... btw, GAO's report "Army's Proposed Close Combat Armored Vehicle Team" (12 dec 1977) has following thing on page 23: and that was BFV project manager's responce (hearings on military posture and h.r. 10929, part 2 of 7, p.183) several mounths later (somewhere in feb-apr 1978):
  22. 11 points
    It's interesting. Presentation (which contains this page) which available now on ontres.se is 110 pages long about 2-and-a-half years ago i've downloaded on my computer presentation which was 119 pages long. Apparently it's exactly the same as one available now online, except for some pages on tank protection https://cloud.mail.ru/public/FVLe/iUZw87trH (according to Chrome history file, which i've backed up in dec.2015 and still have now, this pdf was without a doubt downloaded from ontres.se https://i.imgur.com/ysAJQgr.png) ... new link https://cloud.mail.ru/public/579x/2Z1Bqxm2m
  23. 11 points
    Guide "How to tell the difference between T-90 and T-90A". These are the most visible differences between T-90 and T-90A. I made this guide because I haven't seen any on this topic and majority of people don't even know there are these two variants (there are more) or don't know what is different between them, so I wanted to enlighten people. This guide is not 100% true because there are some "hybrid" T-90 which incorporate parts from both models, for example T-90A chassis (body, new tracks and engine) with T-90 cast turret = T-90K http://live.warthunder.com/post/599752/en/ I didn't incorporated export(T-90S) models because they can be distinguished very easily by the complete lack of Shtora-1 EOCMDAS or by the missing MTShU-1-7 modulator such as T-90SA for Algeria, Armenia and Azerbaijan. I am open to any suggestion or to constructive criticism. I hope this will help.
  24. 11 points
    Waffentrager

    The Japanese Ferdinand

    Disclaimer: Yeah naturally Japanese tanks arent a big focus here, so I usually ignore posting things of the matter here. But like the O-I article I posted here oh so long ago, this article comes with the results of some days spent in the archive reading and (continuing to do) translating pages of reports that havent been read in like, decades. So with that said, hope you enjoy. Still a matter I'm unfinished diving into. --------- Type5 Ho-Ri : The Japanese Ferdinand As of recently, I've gone through the Japanese National Archive files, looking through to find documents that relate to my studies. While I was there, I stumbled across something that caught my interest. Of said documents, the one of most importance was a file called "Military Secrets No.1". The reports were held by the Ministry of Defense, Army records section, Munitions Mobilization district. Contained in these files were a 3-page production chart of late war tracked vehicles of the Japanese army. Located within the chart I found a number besides the Type 5 Ho-Ri tank destroyer. A vehicle that until recently was only known to have made it to wooden mockup stages. In this lengthy article I will cover my findings on the tank project. Unfortunately visual representations of the tank are still being looked at. So I will use existing found sources for this. National Institute for Defense Studies " Military secret No.1 " In September of 1942, the Japanese Army Staff came to the realization that they had no choice but to design a series of tanks to compete with the arrival of the American Sherman tank. Three concepts were proposed by the Staff, each with their own gun selection; Kou (47mm), Otsu (57mm), and Hei (75mm). As combat data filtered back to Japanese high command, the model Kou concept would later merge with Otsu concept, becoming the basis for the design of the Type4 Chi-To. The Hei proposal would eventually lead to the development of the Type5 Chi-Ri. Additional impetus for new development projects came from a change in the Weapons Administration Headquarters Research Policy in July 1943, a change which was made as a result of analyzing and examining the situation of the tank warfare between the German army and the Soviet Union. Through analysis of this data, the Army's tank doctrine shifted to an emphasis on developing tanks which prioritized the anti-armor mission instead of prioritizing infantry support with limited anti-tank capability. Upon the promulgation of this policy, the Japanese Army decided to develop a series of tank destroyers alongside the medium tanks being designed. As a result, the Type5 Chi-Ri, Japan’s primary medium-tank project, would become the basis for a new anti-armor vehicle. This was a natural choice for IJA command; the Chi-Ri project was more mature. Additionally, it held the most advanced technology Japan produced at the time, technology which would become ubiquitous in the designs that would be made until Japan's defeat in 1945. Testing model of Chi-Ri. Used to trial the series of cannons and turrets designed for the tank. In the photograph it is captured by US forces after the gun had been dismantled for further trials. By Japan's defeat in 1945, three models of Chi-Ri entered production. The tank destroyer built upon the chassis of the Chi-Ri would eventually be called the Ho-Ri. Development of this vehicle began shortly after the development of the Chi-Ri, when it had been decided that the tank would use the coil spring suspension system that Japanese manufacturers were already familiar with. After this decision was made, the Army also began work on designing the tank destroyer’s superstructure and casemate. The first design the Army came up with mimicked the Chi-Ri chassis entirely, though the turret was replaced with a reinforced rear-mounted superstructure. The Experimental 10cm Cannon With the development of a new series of tank destroyers taking place, the Army decided to design and produce a new high capacity anti-tank gun to fit the role. On July 22 of 1943, the Army Military Customs Council began designing a 105mm caliber anti-tank gun. Once the design of the cannon had been completed, construction of the cannon took place around a steel shielding that was to be the Ho-Ri's superstructure plating. The trial placement was capable of traversing 10 degrees to the left and the right, elevating by 20 degrees, and depressing by 15. The gun weighed 4.7 tons, with a barrel length of 5.759 m. During one of the first council meetings that took place on the 30th of June, however, the council gave Major Ota and Lieutenant Colonel Neima of the Army Weapons Administrative Division, the two chief engineers of the Experimental 10cm project, the task of achieving the requirement that the gun meet 200mm penetration at 600 meters distance and 1000m/s velocity. Naturally, the tank gun was not capable of this, and, instead, the Experimental 10cm had a muzzle velocity of 915m/s with AP (900m/s with HE), and achieved a performance of 150mm penetration at a distance of 1000 meters. The 10cm Experimental Anti Tank gun relied on a system similar to the Type5 75mm Anti tank cannon in relying on an autoloading mechanism for the tank. This mechanism was known as a semi-automatic loading system, different to the ordinary "autoloader" you see in other vehicles. Unlike the typical autoloading system, the loading crew of the gun system placed the individual shells on the chamber, the system automatically ramming the shell into the breech and forwarding to operation. This gave the effect of automating half the loading routine, as the name suggests. The Experimental 10cm was put into service with the Ho-Ri in 1945. The technical name for the model to be used on the prospective production model was known as the Type5 10cm anti tank cannon. The shell rammer used a horizontal chain closing type, and the automatic loading machine was attached to the back of the gun. It was used because loading ammunition of 123 cm total length and 30 kg weight was deemed too strenuous on a small Japanese physique. Various artillery parts had been diverted and referred to in order to shorten the time of development. The autoloading machine adopted the mechanism of the Type3 12 cm AA Gun for inspiration. The automatic loading mechanism was a continual source of problems, but was repeatedly refurbished to eliminate the drawbacks. Photograph of the Experimental 10cm Anti tank cannon during trials. Note: The shielf and protector are used on Ho-Ri prototype. Gun was first tested separately and then placed in tank prototype. Ho-Ri Designs Originally, the Ho-Ri was to keep the secondary 37mm that had been mounted on the Chi-Ri design. The reason for this addition was due to the limited gun-traverse on casemate tank destroyers. Additionally, the primary cannon could only do so much for itself. Hence, to combat many anti tank threats which the Americans could have dedicated to the assault on Japan, the 37mm was seen as being an efficient method of providing additional firepower against infantry and combat vehicles. To this end, the 37mm gun offered a range of APHE and smoke shells. The 37mm was capable of an elevation of 20 degrees and depression of -15 degrees. The mount itself also offered a horizontal traverse of 20 degrees. The 37mm gun could also be used as a ranging device for the main cannon, however this most likely would not have been needed due to the high velocity of the main gun. Outline of the Ho-Ri design I. Technically entered modified construction of one of the 3 Chi-Ri units. The development of the Ho-Ri design was split into two concepts. One being a rear mounted superstructure on the Chi-Ri chassis with a central stationed engine, and the other having a centralized superstructure with a rear engine placement. The Ho-Ri engine selection was different from the traditional diesel that the Army had kept with for most of their tank production. Japan used a BMW designed gasoline V12 aircraft engine . The main reason for this change was due to industrial capacity of Japan reaching its peak, aircraft development was still a heavy priority and many assets were available for useage. The output of the tank was 550hp/1500rpm. The Ho-Ri II’s design also enabled the option of adding a 20mm AA station on the rear hatch for additional protection. However, the likelihood of it being useful is up for debate. In addition, central placement of the superstructure enabled 60 rounds for the main cannon to be stored instead of the Ho-Ri I’s 40 rounds. In terms of armour, both vehicles were to keep the Chi-Ri hull, hence the maximum frontal armour of these tanks was only 75mm. On the superstructure, however, armor thickness was increased to 100mm. By the time both designs, which had been developed in parallel, were presented to Army General Staff it was too late; the war was almost over, and the thickness of the armor was no longer sufficient against US armaments. Nevertheless, the design showed promise. Thus, while neither design was chosen for production, the Ho-Ri I was adopted as the main influence for the third revision of the tank. This third vehicle is commonly labeled as Ho-Ri III. Technically, however, none of the Ho-Ri vehicles were numerically designated. Ho-Ri III wooden mockup. Ho-Ri III took the basis of the Ho-Ri I, and revamped it to fit the needs of the military. The frontal plate of the tank was sloped at a 70 degree angle and increased to 120mm thickness. In this configuration, the tank was capable of withstanding most anti tank measures the Unites States could bring to the home islands of Japan. The designers of the tank built a wooden mockup form of the revision 3 design and presented it to the general staff, at an unknown date. The Ho-Ri kept its general composition the same as the prior designs, but this change was what the Army Staff ultimately decided to go with and schedule the Ho-Ri for prototype construction. The tank would have a crew total of 6; driver, gunner, two loaders, radio operator, and commander. The past designs made use of the 37mm that the Chi-Ri hull had present, however, with the chosen slope change on the Ho-Ri III, this was no longer present and a crew member spot was open. The 6th crew member was placed as the second loader to assist with the autoloading mechanism and provide shells for the primary loader. The construction of the prototype was completed in 1944. The tank achieved a speed of 40kmh during the trials. The tests were seen as a success, resulting in the Army ordering 5 units of the tank. The tank was put in service as the Type5 Ho-Ri, as the production model started in 1945. However, by the time of the war's end, the series of tanks only made it to 50% completion. Only one operable prototype had been completed fully. Reports of the trial are still being processed at this time [11/15/16]. My research continues. I have been spending days now trying to go through everything and get the details of the tank out to the light. Once all the documents are collected together and organized, translated, and put back together I will write a follow up article to this. You can view full post with all images on my blog post: http://sensha-manual.blogspot.com/2016/11/type5-ho-ri-japanese-ferdinand.html
  25. 11 points
    Waffentrager

    Japans Box Tank O-I

    O-I The O-I (オイ車 Oi-sensha) was a super-heavy tank prototype designed by the Imperial Japanese Army during the Second Sino-Japanese War after the Battles of Nomonhan in 1939. The O-I is one of the Second World War’s more secretive tank projects, with documentation regarding the tank being kept private for over 75 years at Wakajishi Shrine, Fujinomiya. Surviving files have been purchased by FineMolds Inc., and publicly previewed in mid-2015. The multi-turreted 150-ton tank was designed for use on the Manchurian plains as a supportive pillbox for the Imperial Japanese against the Soviet Union. The project was disbanded four years after the initial development began, deemed unsatisfactory for continuation in 1943 after the lack of resource material for the prototype. History and development After 1939, the Imperial Japanese Army quickly came to realize that previous forms of mechanized warfare were proved inefficient after their defeat at Khalkhin Gol. Development of the super-heavy project was spearheaded by Colonel Hideo Iwakuro, the head of the Ministry of War of Japan (陸軍省 Rikugun-shō). Iwakuro opposed Japan’s advances towards the Soviet Union in 1939, and with the Japanese defeat, he decided to initiate a project to construct a heavily armored tank capable of withstanding large-caliber field cannons. Iwakuro assigned Colonel Murata of the 4th Technical Research Group to design and construct the super heavy tank in 1939. Colonel Murata noted Iwakuro’s words as described; 「満州の大平原で移動トーチカとして使えるような巨大戦車を作ってほしい。極秘でだ。」 “I want a huge tank built which can be used as a mobile pillbox in the wide open plains of Manchuria. Top secret.” 「今の戦車の寸法を2倍に延ばして作れ。」 “Make the dimensions twice that of today’s tanks.” The 4th Technical Research Group began designing the super-heavy vehicle throughout 1940, attempting to meet Colonel Iwakuro’s vague instructions on the ultimate goal of the project. By March 1941, the research group had finished initial tank design and was ready to begin construction. The following month, a group of pre-selected engineers were chosen to partake in the building of the super-heavy tank. One recorded engineer was Shigeo Otaka, who stated they were sent to the 4th Technical Research Group’s previous headquarters in Tokyo. There, they were guided through a barracks containing multiple small fitting rooms, where they were to conduct meetings and reports on the progress of construction of the super-heavy vehicle. Towards the end of the barracks facility was a fully-enclosed room devoid of windows, with soundproofed walls to prevent external personnel from overhearing discussions related to the project. Each officer present possessed a portion of the project’s blueprint, which, when assembled, projected the full design of the tank, labeled "Mi-To". The name originated from a collection of the Mitsubishi industry and the city, Tokyo; given to the vehicle to uphold secrecy of the tank’s project. Colonels Murata and Iwakuro The chosen engineers voiced their concerns regarding the Mi-To’s design noting that previously, the largest-sized Japanese tank had been the prototype Type95 Heavy in 1934. Issues that had been noted with heavy tank experiments in the years preceding the Mi-To showing Japan’s generally unsuccessful testing on multi-turreted vehicles exceeding the weight of standard armored vehicles. However, with the threat of a second Russo-Japanese conflict becoming more apparent, the project continued despite the engineer’s doubts on the size and mobility of the vehicle. Four engineers who survived to record the dealing had with the project On April 14th 1941, the engineers began the construction of the Mi-To under secretive means. This entailed privately-made mechanical parts and equipment being shipped to the construction zone. Colonel Murata’s original concept was to complete the super-heavy tank three months after the initiation of Mi-To’s construction. This, ultimately, did not come into fruition; as technical issues on the project began to arise. Due to the limitation on material consumption by the government, the amount of parts that could be secretly shipped-in began to dwindle. By the first month of construction, essential construction resources had been depleted and the issues with the vehicle’s cooling system further caused delays. The construction of the Mi-To was postponed until January 1942, a delay of nine months. After the Mi-To’s construction was resumed, the hull was completed on February 8th 1942. The tank had reached near-completion and was being prepared for mobility testing. Mitsubishi built the four turrets for the tank in May of the same year. Initial assembly of the tank’s armament took place soon after the turret’s superstructures were completed. However; the project once again did not have the necessary resources needed for the few remaining parts required for the final assessment. Due to this, the primary turret was removed as it lacked a 35-millimeter-thick roof plate, which had not yet arrived. Thus, the project was put on standby, until further development could continue. The total weight of the vehicle at the time was 96 tons, due to the lack of remaining structural plates and absent 75mm bolted-on armor. O-I documents previewed by FineMolds The date on which the construction of the tank resumed is unknown, although active testing of the tank was scheduled for late 1943. The tank was unveiled to the Imperial Japanese Army’s highest command in 1943, and received a name change to O-I. This followed Japanese naming convention (O translating to Heavy, I for First, making it "First Heavy") that was standard. In his place was Lieutenant Colonel Nakano, Murata's assistant and colleague. Tomio Hara, head of the Sagamia Army Arsenal, was also present. Following the demonstration, senior officials within the IJA requested that field trials begin in August of the same year. The tank was disassembled at 2:00 AM one night in June of 1943 and sent to the Sagami Army Arsenal in Sagamihara, 51 kilometers from Tokyo. The vehicle arrived at the depot in June, and was reassembled and tested on the 1st of August. On the day of the trials, the O-I performed satisfactorily until the second hour of the tests. While maneuvering on off-road terrain, the tank sank into the ground by up to a meter; attempts at traversing the hull to extricate the vehicle proved fruitless, resulting in further sinking due to the vehicle’s suspension coils compressing. The tank was eventually towed out, and further testing was continued on concrete. However, the earlier damage to the suspension resulted in vehicle’s movement damaging the concrete, which in turn, further damaged the suspension bogies to the point that further testing could not continue. The trials were postponed, and later canceled the following day. Nevertheless, the trials conducted at the testing field were considered to be a success, and the vehicle was deemed ready for use in spite of its flaws. The engineers began disassembly of the tank on the 3rd of August due to resources being limited and the inability to maintain the tank in the field. Disassembly of the tank was completed on August 8th. Two days later, the engineers noted in a log that they were to inspect the parts and conduct research to fix the issues the O-I would face. The fate of the O-I after its field-trials which took place on the 1st of August is unclear. Russian reports claim the Japanese were in possession of a wooden O-I mock-up mounting a Daimler-Benz DB 601A engine in 1945, however other sources point to the scrapping of the remaining parts of the same year. The remains of the O-I reside at the Wakajishi Shrine, with a track link of the prototype still present. Remaining track link of the prototype O-I tank Design The O-I was conceived out of the necessity to produce an armored vehicle capable of withstanding modern weaponry being able to return fire with similar firepower. The O-I was designed to act as a mobile pillbox, supporting infantry and mechanized groups along the border of the Soviet Union. The tank had a length of 10.1 meters, width of 4.8 meters, and a height of 3.6 meters. The dimensions of the vehicle closely matched those of the Panzer VIII Maus. The tank was envisioned to have a standard thickness of 150 millimeters front and rear, in order to protect against common anti-tank weapons of the time, yet it was constructed with armor 75 millimeters thick. However, an additional armor plate could be bolted on to bring the total thickness of the armor to 150 millimeters. The use of additional armor allowed for ease of construction and transportation, while also providing the tank with additional defense. Side armor on the hull superstructure was 70 millimeters thick. The additional armor plates were 35 millimeters thick, but armor surrounding the suspension was only 35 millimeters thick. This made the tank’s theoretical armor on the side 75 millimeters. There were eight wheel-supporting beams located on both sides of the suspension area which added an additional 40 millimeters of armor to specific locations on the side of the O-I. 40 ladder pieces were placed around the tank to provide crew with the ability to climb onto of the vehicle with ease. The two 47mm cannons used in the two frontal turrets were also modified to fit the armor layout of the tank. The weapon’s barrels were reinforced with steel to secure them to the tank, due to the standard gun not adequately fitting into the turret. The tank was both designed and built with two inner armor plates to divide the interior into three sections; walls with two doors each and an ultimate thickness of 20mm. This allowed the crew and modules to remain relatively safe while the structure was kept safe with supporting stands. These supports allowed the interior armor plates to stay stable and also prevented collapse. Inside the O-I were two Kawasaki V-12 engines, both located in the rear, parallel lengthwise, to give room for the rear turret operator and transmission. The transmission copied that of the Type97 Chi-Ha’s, but used larger parts and gears making the total weight heavier. The vehicle had a coil spring system, with eight 2 wheeled boggies, totaling 16 individual wheels. Data Sheet Sources - O-I documentation, Finemolds - O-I project report notebook 1,2,3,4,5, and 6 (Finemolds) - JP Tank Perfect Guide - 日本の戦車 原乙未生 (Hara's book) (Old sources) - 帝国陸軍陸戦兵器ガイド1872-1945 - 日本陸軍の火砲 野戦重砲 - 戦車と戦車戦 - 太平洋戦争秘録 日本・秘密兵器大全 ---------------------- ​Since the article Soukou and Daigensui wrote long ago is filled with inconsistencies and errors, decided to make something thats actually accurate to the reports. Wrote it on Google Docs initially, posted it to WT earlier. Will be present on Ritas blog and eventually Wikipedia.
  26. 11 points
    EnsignExpendable

    HEAT for Dummies

    Neat video showing off how HEAT shells work. The guy detonates 4 charges, one that's just explosive, one with explosive that has an indentation in it, then one with an explosive that has an indentation in it that's filled with metal, and finally, the same charge as in part 3, but at a small offset to focus the blast.
  27. 10 points
    Sovngard

    Britons are in trouble

    Vickers Valiant on a muddy track : Barr & Stroud LF 11 gunner sight and the Pilkington PE Condor commander day/night sight : Hull ammo rack (30x105 mm) and driver's compartment, the handlebar features a throttle twist grip : VR 1000 powerpack comprising the Rolls-Royce CV12TCA Condor 1000 hp engine and the TN 12-1000 automatic transmission : The pyramidal louvers above the transmission are typical of the Valiant.
  28. 10 points
    Militarysta

    Polish Armoured Vehicles

    This time, photo taken by myself. APC Rosomak firing single 81mm camouflage granate GAK-81 single 81mm in 1st salvo: and single 81mm in 2th salvo: And this one was mucht difficult due to weather conditions. Six 120mm motar round on one picture: And twins: And the result: In summary - 120mm SMK Rak is very good weapons, very powerfull modern and now the best serial produce in the world. Nice that at least one type of weapons producing in my country can be on top lvl...
  29. 10 points
    Stimpy75

    Turkish touch

    i am really exhausted my feet are killin me first i will try google pics if it doesnt i have to upload them to imgur feel free to share them(except for tanknet.forum! F.U. tanknet!) https://photos.app.goo.gl/hSSBM66MUsiYTteC8
  30. 10 points
    I made a model of the T-34M: Astute viewers will notice that the commander's cupola is wrong - it's supposed to be a T-50 cupola rather than the T-34/85 model I stuck on. Rivet counters will notice that the exhausts don't have the crazy bolt arrangement they should have (and are kind of the wrong shape), the front hooks are missing, the radio antenna is missing, the hull periscopes are missing, and that the turret periscopes are of the wrong type.
  31. 10 points
    LoooSeR

    Competition: Tank Design 2239

    After 23 days of drinking booze and random disappearing, judges finally picked winners of this competition! In a 45 ton category we came to the conclusion that a member of this forum, who only recently joined to us, was able to surpass all other contestants with his tank design. He earns a title of The Glorious Tank Autist of SH - comrade @N-L-M! His XM-2239 "Norman" tank was chosen by all judges as the best submissions of this competition. His work was fighting with Toxn's heavy tank for a 1st place, and managed to overtake it. @Sturgeon's XM12 "Donward" was disqualified from the competition as it was not fitting into one of basic requirements (width, 3.35 meters without skirts vs 3.25 meters required). @A. T. Mahan's 120mm gun tank T44 also was disqualified for use of armor tech that was out of competition-imposed industrial capabilities limitation (1940-1950s level of tech) @ApplesauceBandit's AFVs were also not in a competition as submission was lacking in any stats, so we couldn't understand if vehicle fits into basic requirements. In 25 ton category a rivalry was stronger as more light tanks proposals managed to get through basic requirements. Judges examined several war vehicles proposed by A.T. Mahan, Sturgeon, NLM, Toxn, and made their choice. The winner of this category is no other than a Supreme Warrior of Napkinpanzers comrade @Toxn!* *vehicle should receive a change in co-axial MG placement, as now it is a danger for driver's head when he is entering/exiting his station or anytime when he have his head outside of the hatch. Our Great AFV designer Toxn pictured with tank drivers that his tank is going to kill before modernization programm will be launched to reposition co-axial MG to a safer place. Place for a memorial is ready to accept new heroes of SH Tank design bureau.** **Not in Kharkov Winners of this competition now should receive their prizes, after that - locked in their houses and allowed to get out only to work on AFV designs until retirement.
  32. 10 points
    Hello everyone! I've made some videos concerning topics of military, strategy, technology and so on. So far I'm getting pretty good feedback on them so maybe you too would be interested in seeing them. Here's one on Turkey vs Russia: hypothetical air war Or US AMRAAM D missile compared to Russian R-77-1 missile Or UK vs France: hypothetical war So tell me what you think!
  33. 10 points
    Alzoc

    Documents for the Documents God

    SGA made 299 plans of the AMX factory available online. Ranging from 1936 to 1959 with a few documents on the M4A4 but also the Pz IV (suspension) and the Panther. http://www.memoiredeshommes.sga.defense.gouv.fr/fr/arkotheque/navigation_facette/index.php?f=Blindes&mde_present=mosaique&debut=0
  34. 10 points
    LoooSeR

    GLORIOUS T-14 ARMATA PICTURES.

    Basically what this whole thing means is that Emperor Palputin will conquer Galaxy with Space Marines and T-72s. T-72B3s to be precise. I posted this on other Capitalist internet site 3 months ago And apperently this is very likely to be now true after Borisov's stupid speech. UBKh is T-72B3 mod 2016/"M". So let's look at this situation - we have no new produced tanks delivered to RA since 2010-2011 (T-90A production was stopped for T-72B[udget Cuts]3) and there will be no newly produced tanks in any meaningful numbers for 5-10+ more years. Which leave our non-courtiers soldiers with existing fleet of Soviet tanks, which are at least 30+ old. Add here a fact that Soviets human-hating godless commies did worked on new generation of MBTs in late 1980s to seriusly/radically change tank designs, you can see that those tanks were becoming outdated in even 1980s. Similar situation is with IFVs and APCs, with BMP-3 being produced in too small numbers and majority of our fleet is BMP-2s and BTR-80As. On top of that political and military situation, and recent history shows that our forces are going to be involved in number of local conflicts (Chechnya, Georgia, Ukraine, Syria, etc) where our nuclear-powered "Putin Fury" cruise missiles and nuclear powered ekranoplans with nuclear powered teapots will make 0 difference. Majority of our potential enemies/opponents have Soviet weaponry, from RPGs down to S-300s, Smerch/Uragan MRLS and so on. Not only potential, but enemies that we already fought have them and actively use them. In Soviet times, during A-stan war BMPs for example already received armor upgrades (BMP-2D), even against not that well equipped dushmans and mujaheeds. Object 477 had serious side armor package and separated crew compartment, Object 299 had crew protection capsule and so on. Basically, armor and survivability of older vehicles in changing type of conflicts that Soviet army found itself, were already found to be "lacking". Our MoD decision to this problem of aging and outdated park of tanks, IFVs and APCs of army that is going (and already does) fight with relatively not badly armed forces is this: take T-72B, glue French thermal imager and FCS from 2000s, repair all parts that responsible for moving tank from point A to point B and call it "B3", done take BMP-2, add new radio, done take BMP-1, put BTR-80A turret with 30 mm "i can't hit anything" autocannon, done Take BTR-80 and put a turret with 30 mm "i can't hit anything" autocannon, done Create a TV channel (let's call it "Zvezda") and use all central TV channels, internet sites and so on to tell general public that our tanks are most tankiest ever made, APCs are unpenetretable and T-72 can beat Abrams and Leopards 2 left and right with just fumes from diesel engines and driver swearing something in Russian from his open hatch. Somebody think that this will be enough, but there are a lot of problems here that were not solved. We are stuck with 30+, 40+ and in case of Basurmanin program - a fucking 50+ old vehicles. Simply speaking our soldiers are going to next conflict on top of IFVs that were taken out from Army during Soviet times because they were deemed outdated! Why this situation is so stupid? During 2000s we already had plenty to work with. BTR-90 for APCs could be at least something (chassis could support more weight, better armor, more place for turret and weapons, etc), tanks could be upgraded under Burlak program, or Black Eagle could have been developed futher. A lot of resources were put into BTR-90s, Burlak programm with real vehicles made for them. And nothing came from them because funding was stopped on premise of creation of better vehicles in the future. BMP-3 armor upgrades, APS, Relikt, T-72B2 Rogatka, Object 187, etc, a lot of stuff that was mass production ready or nearly ready was not put on conveyor at least in small numbers for active units participating in wars. A lot of wasted time and money. At least with those vehicles we could had something for Army created and produced in this century that at least partially solves problems that Soviet human-hating commies wanted to solve. How many years ago was Object 195 tested? Why they couldn't put those in limited service/test phase? Again, claims of better tank in the future, while army is still sitting on T-72Bs with K-5 and shells under crew bare asses. Years and years of development for some perfect weapon system that lead to nothing in the end while this whole time T-72Bs did not even got Relikt ERA as a cheap-ass upgrade. And only in 2016 an upgrade from 2000s was put into limited use on uparmored T-72B3s. But problems are not stopped here. After collapse of Soviet union we got a pretty good opportunity to solve another problem from late Soviet times - a whole 3 "Main" battle tanks in service that had almost no shared parts but very similar perfomance. Kharkovite traitors now were outsiders, T-80 developers and producers went into bankrupt trash bin and only UVZ left. We could finaly get a standart MBT, without zoological garden of different designs, parts, training, etc. But apperently this is not a case. We now have zoological garden of T-72s, with T-80UE/UA/BVM on top of that and T-90/A/M getting into mix. Same with IFVs - BMP-3 now have to share their role with BMP-2/M and BMP-1 Basurmanin. Well, at least BTR-80A is not in danger in any way as BTR-90 is a dead project. Add here all those MRAPS (Ural-VV, Typhoon-U, Typhoon-K, and so on) for special type of "fuck you, standardization". So good luck to our soldiers with T-72, in 2020, 2030 and maybe 2040 and thanks to Soviet un-orthodox evil empire for providing our MoD with at least something to fight and die in, because with this level of excellent planning and holistic vision of Armed forces our MoD would had to use Toyotas to close gaps and cover a hole in their pants and underpants. But i fear that someday T-72s will no longer be avaliable for B3 "modernization" and Soviet stocks would be 100% used... maybe T-34 needs some sort of modernization? Like T-34B3? It probably will be better than all Western tanks and can beat M1A3 Abrams and Leopards 3s left and right with just fumes from diesel engines and driver swearing something in Russian from his open hatch.
  35. 10 points
  36. 10 points
    You're terrible at communicating, and what you say doesn't make any sense. I am going to patiently explain why you're terrible and suck, and if you don't start improving I am going to take unfair and hilarious punitive measures, like editing your posts in ways I find humorous and disallowing you to edit them yourself. This is more warning than anyone deserves or generally gets, but it's monday and I'm lazy and hungover, so I have no inclination to do more productive things than argue on the internet. Which value needs to be multiplied by 50%? Why? As EE explains it, the Soviet criterion is a circle within which you would expect 50% of the hits to land (it's exactly the same thing as Circular Error Probable). The German criterion is a rectangular shape within which you would expect 50% of the hits to land. Nothing about this screams that there is a dropped factor of two in this conversion. If you actually have a point, you need to clearly and completely articulate it, or nobody will take you seriously. If you complain that nobody is taking you seriously, you should seriously consider the possibility that you suck at communicating. If, for instance, you had pointed out that German AFV optics had thin-film electro-deposited coatings while others did not, and linked this excellent report on the history and physics of thin-film optical coatings, that would have been a useful contribution. Or if you had found a table comparing light transmission of AFV optics (these exist, some of the Aberdeen reports measure it, for instance). Or magnification vs field of view. Any of those things would have contributed to the conversation. But you haven't contributed at all. You have claimed that there are "facts" backing up your point of view, but you have so far refused to provide them. That's youtube comments section level of retarded flailing. I have no time for youtube comments section retards. So shape up or suffer my depravity.
  37. 10 points
    Collimatrix

    Top Speed in Tanks

    Tank design is often conceptualized as a balance between mobility, protection and firepower. This is, at best, a messy and imprecise conceptualization. It is messy because these three traits cannot be completely separated from each other. An APC, for example, that provides basic protection against small arms fire and shell fragments is effectively more mobile than an open-topped vehicle because the APC can traverse areas swept by artillery fires that are closed off entirely to the open-topped vehicle. It is an imprecise conceptualization because broad ideas like "mobility" are very complex in practice. The M1 Abrams burns more fuel than the Leo 2, but the Leo 2 requires diesel fuel, while the omnivorous AGT-1500 will run happily on anything liquid and flammable. Which has better strategic mobility? Soviet rail gauge was slightly wider than Western European standard; 3.32 vs 3.15 meters. But Soviet tanks in the Cold War were generally kept lighter and smaller, and had to be in order to be moved in large numbers on a rail and road network that was not as robust as that further west. So if NATO and the Warsaw Pact had switched tanks in the late 1950s, they would both have downgraded the strategic mobility of their forces, as the Soviet tanks would be slightly too wide for unrestricted movement on rails in the free world, and the NATO tanks would have demanded more logistical support per tank than evil atheist commie formations were designed to provide. So instead of wading into a deep and subtle subject, I am going to write about something that is extremely simple and easy to describe in mathematical terms; the top speed of a tank moving in a straight line. Because it is so simple and straightforward to understand, it is also nearly meaningless in terms of the combat performance of a tank. In short, the top speed of a tank is limited by three things; the gear ratio limit, the power limit and the suspension limit. The tank's maximum speed will be whichever of these limits is the lowest on a given terrain. The top speed of a tank is of limited significance, even from a tactical perspective, because the tank's ability to exploit its top speed is constrained by other factors. A high top speed, however, looks great on sales brochures, and there are examples of tanks that were designed with pointlessly high top speeds in order to overawe people who needed impressing. When this baby hits 88 miles per hour, you're going to see some serious shit. The Gear Ratio Limit Every engine has a maximum speed at which it can turn. Often, the engine is artificially governed to a maximum speed slightly less than what it is mechanically capable of in order to reduce wear. Additionally, most piston engines develop their maximum power at slightly less than their maximum speed due to valve timing issues: A typical power/speed relationship for an Otto Cycle engine. Otto Cycle engines are primitive devices that are only used when the Brayton Cycle Master Race is unavailable. Most tanks have predominantly or purely mechanical drivetrains, which exchange rotational speed for torque by easily measurable ratios. The maximum rotational speed of the engine, multiplied by the gear ratio of the highest gear in the transmission multiplied by the gear ratio of the final drives multiplied by the circumference of the drive sprocket will equal the gear ratio limit of the tank. The tank is unable to achieve higher speeds than the gear ratio limit because it physically cannot spin its tracks around any faster. Most spec sheets don't actually give out the transmission ratios in different gears, but such excessively detailed specification sheets are provided in Germany's Tiger Tanks by Hilary Doyle and Thomas Jentz. The gear ratios, final drive ratios, and maximum engine RPM of the Tiger II are all provided, along with a handy table of the vehicle's maximum speed in each gear. In eighth gear, the top speed is given as 41.5 KPH, but that is at an engine speed of 3000 RPM, and in reality the German tank engines were governed to less than that in order to conserve their service life. At a more realistic 2500 RPM, the mighty Tiger II would have managed 34.6 KPH. In principle there are analogous limits for electrical and hydraulic drive components based on free speeds and stall torques, but they are a little more complicated to actually calculate. Part of the transmission from an M4 Sherman, picture from Jeeps_Guns_Tanks' great Sherman website The Power Limit So a Tiger II could totally go 34.6 KPH in combat, right? Well, perhaps. And by "perhaps," I mean "lolololololol, fuck no." I defy you to find me a test report where anybody manages to get a Tiger II over 33 KPH. While the meticulous engineers of Henschel did accurately transcribe the gear ratios of the transmission and final drive accurately, and did manage to use their tape measures correctly when measuring the drive sprockets, their rosy projections of the top speed did not account for the power limit. As a tank moves, power from the engine is wasted in various ways and so is unavailable to accelerate the tank. As the tank goes faster and faster, the magnitude of these power-wasting phenomena grows, until there is no surplus power to accelerate the tank any more. The system reaches equilibrium, and the tank maxes out at some top speed where it hits its power limit (unless, of course, the tank hits its gear ratio limit first). The actual power available to a tank is not the same as the gross power of the motor. Some of the gross horsepower of the motor has to be directed to fans to cool the engine (except, of course, in the case of the Brayton Cycle Master Race, whose engines are almost completely self-cooling). The transmission and final drives are not perfectly efficient either, and waste a significant amount of the power flowing through them as heat. As a result of this, the actual power available at the sprocket is typically between 61% and 74% of the engine's quoted gross power. Once the power does hit the drive sprocket, it is wasted in overcoming the friction of the tank's tracks, in churning up the ground the tank is on, and in aerodynamic drag. I have helpfully listed these in the order of decreasing importance. The drag coefficient of a cube (which is a sufficiently accurate physical representation of a Tiger II) is .8. This, multiplied by half the fluid density of air (1.2 kg/m^3) times the velocity (9.4 m/s) squared times a rough frontal area of 3.8 by 3 meters gives a force of 483 newtons of drag. This multiplied by the velocity of the tiger II gives 4.5 kilowatts, or about six horsepower lost to drag. With the governor installed, the HL 230 could put out about 580 horsepower, which would be four hundred something horses at the sprocket, so the aerodynamic drag would be 1.5% of the total available power. Negligible. Tanks are just too slow to lose much power to aerodynamic effects. Losses to the soil can be important, depending on the surface the tank is operating on. On a nice, hard surface like a paved road there will be minimal losses between the tank's tracks and the surface. Off-road, however, the tank's tracks will start to sink into soil or mud, and more power will be wasted in churning up the soil. If the soil is loose or boggy enough, the tank will simply sink in and be immobilized. Tanks that spread their weight out over a larger area will lose less power, and be able to traverse soft soils at higher speed. This paper from the UK shows the relationship between mean maximum pressure (MMP), and the increase in rolling resistance on various soils and sands in excruciating detail. In general, tanks with more track area, with more and bigger road wheels, and with longer track pitch will have lower MMP, and will sink into soft soils less and therefore lose less top speed. The largest loss of power usually comes from friction within the tracks themselves. This is sometimes called rolling resistance, but this term is also used to mean other, subtly different things, so it pays to be precise. Compared to wheeled vehicles, tracked vehicles have extremely high rolling resistance, and lose a lot of power just keeping the tracks turning. Rolling resistance is generally expressed as a dimensionless coefficient, CR, which multiplied against vehicle weight gives the force of friction. This chart from R.M. Ogorkiewicz' Technology of Tanks shows experimentally determined rolling resistance coefficients for various tracked vehicles: The rolling resistance coefficients given here show that a tracked vehicle going on ideal testing ground conditions is about as efficient as a car driving over loose gravel. It also shows that the rolling resistance increases with vehicle speed. A rough approximation of this increase in CR is given by the equation CR=A+BV, where A and B are constants and V is vehicle speed. Ogorkiewicz explains: It should be noted that the lubricated needle bearing track joints of which he speaks were only ever used by the Germans in WWII because they were insanely complicated. Band tracks have lower rolling resistance than metal link tracks, but they really aren't practical for vehicles much above thirty tonnes. Other ways of reducing rolling resistance include using larger road wheels, omitting return rollers, and reducing track tension. Obviously, there are practical limits to these approaches. To calculate power losses due to rolling resistance, multiply vehicle weight by CR by vehicle velocity to get power lost. The velocity at which the power lost to rolling resistance equals the power available at the sprocket is the power limit on the speed of the tank. The Suspension Limit The suspension limit on speed is starting to get dangerously far away from the world of spherical, frictionless horses where everything is easy to calculate using simple algebra, so I will be brief. In addition to the continents of the world not being completely comprised of paved surfaces that minimize rolling resistance, the continents of the world are also not perfectly flat. This means that in order to travel at high speed off road, tanks require some sort of suspension or else they would shake their crews into jelly. If the crew is being shaken too much to operate effectively, then it doesn't really matter if a tank has a high enough gear ratio limit or power limit to go faster. This is also particularly obnoxious because suspension performance is difficult to quantify, as it involves resonance frequencies, damping coefficients, and a bunch of other complicated shit. Suffice it to say, then, that a very rough estimate of the ride-smoothing qualities of a tank's suspension can be made from the total travel of its road wheels: This chart from Technology of Tanks is helpful. A more detailed discussion of the subject of tank suspension can be found here. The Real World Rudely Intrudes So, how useful is high top speed in a tank in messy, hard-to-mathematically-express reality? The answer might surprise you! A Wehrmacht M.A.N. combustotron Ausf G We'll take some whacks at everyone's favorite whipping boy; the Panther. A US report on a captured Panther Ausf G gives its top speed on roads as an absolutely blistering 60 KPH on roads. The Soviets could only get their captured Ausf D to do 50 KPH, but compared to a Sherman, which is generally only credited with 40 KPH on roads, that's alarmingly fast. So, would this mean that the Panther enjoyed a mobility advantage over the Sherman? Would this mean that it was better able to make quick advances and daring flanking maneuvers during a battle? No. In field tests the British found the panther to have lower off-road speed than a Churchill VII (the panther had a slightly busted transmission though). In the same American report that credits the Panther Ausf G with a 60 KPH top speed on roads, it was found that off road the panther was almost exactly as fast as an M4A376W, with individual Shermans slightly outpacing the big cat or lagging behind it slightly. Another US report from January 1945 states that over courses with many turns and curves, the Sherman would pull out ahead because the Sherman lost less speed negotiating corners. Clearly, the Panther's advantage in straight line speed did not translate into better mobility in any combat scenario that did not involve drag racing. So what was going on with the Panther? How could it leave everything but light tanks in the dust on a straight highway, but be outpaced by the ponderous Churchill heavy tank in actual field tests? Panther Ausf A tanks captured by the Soviets A British report from 1946 on the Panther's transmission explains what's going on. The Panther's transmission had seven forward gears, but off-road it really couldn't make it out of fifth. In other words, the Panther had an extremely high gear ratio limit that allowed it exceptional speed on roads. However, the Panther's mediocre power to weight ratio (nominally 13 hp/ton for the RPM limited HL 230) meant that once the tank was off road and fighting mud, it only had a mediocre power limit. Indeed, it is a testament to the efficiency of the Panther's running gear that it could keep up with Shermans at all, since the Panther's power to weight ratio was about 20% lower than that particular variant of Sherman. There were other factors limiting the Panther's speed in practical circumstances. The geared steering system used in the Panther had different steering radii based on what gear the Panther was in. The higher the gear, the wider the turn. In theory this was excellent, but in practice the designers chose too wide a turn radius for each gear, which meant that for any but the gentlest turns the Panther's drive would need to slow down and downshift in order to complete the turn, thus sacrificing any speed advantage his tank enjoyed. So why would a tank be designed in such a strange fashion? The British thought that the Panther was originally designed to be much lighter, and that the transmission had never been re-designed in order to compensate. Given the weight gain that the Panther experienced early in development, this explanation seems like it may be partially true. However, when interrogated, Ernst Kniepkamp, a senior engineer in Germany's wartime tank development bureaucracy, stated that the additional gears were there simply to give the Panther a high speed on roads, because it looked good to senior generals. So, this is the danger in evaluating tanks based on extremely simplistic performance metrics that look good on paper. They may be simple to digest and simple to calculate, but in the messy real world, they may mean simply nothing.
  38. 10 points
    Sturgeon's House management does not endorse the views and statements contained in its user-generated content. All views and opinions expressed are those of the author and do not necessarily reflect the official doctrine on which populations are sub-human and must be exterminated.
  39. 10 points
    Today marks the 70th anniversary of the Trinity test. 70 years ago today, in a remote part of southern New Mexico, a fission chain reaction started on Earth for the first time in billions of years.
  40. 9 points
    2805662

    Modern Tank Destroyers / Gun Carriers

    Got to sneak a peak at this today:
  41. 9 points
    N-L-M

    Competition: Californium 2250

    Restricted: for Operating Thetan Eyes Only By order of Her Gracious and Serene Majesty Queen Diane Feinstein the VIII The Dianetic People’s Republic of California Anno Domini 2250 SUBJ: RFP for new battle tank 1. Background. As part of the War of 2248 against the Perfidious Cascadians, great deficiencies were discovered in the Heavy tank DF-1. As detailed in report [REDACTED], the DF-1 was quite simply no match for the advanced weaponry developed in secret by the Cascadian entity. Likewise, the DF-1 has fared poorly in the fighting against the heretical Mormonhideen, who have developed many improvised weapons capable of defeating the armor on this vehicle, as detailed in report [REDACTED]. The Extended War on the Eastern Front has stalled for want of sufficient survivable firepower to push back the Mormon menace beyond the Colorado River south of the Vegas Crater. The design team responsible for the abject failure that was the DF-1 have been liquidated, which however has not solved the deficiencies of the existing vehicle in service. Therefore, a new vehicle is required, to meet the requirements of the People’s Auditory Forces to keep the dream of our lord and prophet alive. Over the past decade, the following threats have presented themselves: A. The Cascadian M-2239 “Norman” MBT and M-8 light tank Despite being approximately the same size, these 2 vehicles seem to share no common components, not even the primary armament! Curiously, it appears that the lone 120mm SPG specimen recovered shares design features with the M-8, despite being made out of steel and not aluminum like the light tank. (based on captured specimens from the battle of Crater Lake, detailed in report [REDACTED]). Both tanks are armed with high velocity guns. B. The Cascadian BGM-1A/1B/1C/1D ATGM Fitted on a limited number of tank destroyers, several attack helicopters, and (to an extent) man-portable, this missile system is the primary Cascadian anti-armor weapon other than their armored forces. Intelligence suggests that a SACLOS version (BGM-1C) is in LRIP, with rumors of a beam-riding version (BGM-1D) being developed. Both warheads penetrate approximately 6 cone diameters. C. Deseret tandem ATR-4 series Inspired by the Soviet 60/105mm tandem warhead system from the late 80s, the Mormon nation has manufactured a family of 2”/4” tandem HEAT warheads, launched from expendable short-range tube launchers, dedicated AT RRs, and even used as the payload of the JS-1 MCLOS vehicle/man-portable ATGM. Both warheads penetrate approximately 5 cone diameters. D. Cascadian HEDP 90mm rocket While not a particularly impressive AT weapon, being of only middling diameter and a single shaped charge, the sheer proliferation of this device has rendered it a major threat to tanks, as well as lighter vehicles. This weapon is available in large numbers in Cascadian infantry squads as “pocket artillery”, and there are reports of captured stocks being used by the Mormonhideen. Warhead penetrates approximately 4 cone diameters. E. Deseret 40mm AC/ Cascadian 35mm AC These autocannon share broadly similar AP performance, and are considered a likely threat for the foreseeable future, on Deseret armored cars, Cascadian tank destroyers, and likely also future IFVs. F. IEDs In light of the known resistance of tanks to standard 10kg anti-tank mines, both the Perfidious Cascadians and the Mormonhideen have taken to burying larger anti-tank A2AD weaponry. The Cascadians have doubled up some mines, and the Mormons have regularly buried AT mines 3, 4, and even 5 deep. 2. General guidelines: A. Solicitation outline: In light of the differing requirements for the 2 theaters of war in which the new vehicle is expected to operate, proposals in the form of a field-replaceable A-kit/B-kit solution will be accepted. B. Requirements definitions: The requirements in each field are given in 3 levels- Threshold, Objective, and Ideal. Threshold is the minimum requirement to be met; failure to reach this standard may greatly disadvantage any proposal. Objective is the threshold to be aspired to; it reflects the desires of the People’s Auditory Forces Armored Branch, which would prefer to see all of them met. At least 70% must be met, with bonus points for any more beyond that. Ideal specifications are the maximum of which the armored forces dare not even dream. Bonus points will be given to any design meeting or exceeding these specifications. C. All proposals must accommodate the average 1.7m high Californian recruit. D. The order of priorities for the DPRC is as follows: a. Vehicle recoverability. b. Continued fightability. c. Crew survival. E. Permissible weights: a. No individual field-level removable or installable component may exceed 5 tons. b. Despite the best efforts of the Agriculture Command, Californian recruits cannot be expected to lift weights in excess of 25 kg at any time. c. Total vehicle weight must remain within MLC 120 all-up for transport. F. Overall dimensions: a. Length- essentially unrestricted. b. Width- 4m transport width. i. No more than 4 components requiring a crane may be removed to meet this requirement. ii. Any removed components must be stowable on top of the vehicle. c. Height- The vehicle must not exceed 3.5m in height overall. G. Technology available: a. Armor: The following armor materials are in full production and available for use. Use of a non-standard armor material requires permission from a SEA ORG judge. Structural materials: i. RHA/CHA Basic steel armor, 250 BHN. The reference for all weapon penetration figures, good impact properties, fully weldable. Available in thicknesses up to 150mm (RHA) or 300mm (CHA). Density- 7.8 g/cm^3. ii. Aluminum 5083 More expensive to work with than RHA per weight, middling impact properties, low thermal limits. Excellent stiffness. Fully weldable. Available in thicknesses up to 100mm. Mass efficiency vs RHA of 1 vs CE, 0.9 vs KE. Thickness efficiency vs RHA of 0.33 vs CE, 0.3 vs KE. Density- 2.7 g/cm^3 (approx. 1/3 of steel). For structural integrity, the following guidelines are recommended: For light vehicles (less than 40 tons), not less than 25mm RHA/45mm Aluminum base structure For heavy vehicles (70 tons and above), not less than 45mm RHA/80mm Aluminum base structure. Intermediate values for intermediate vehicles may be chosen as seen fit. Non-structural passive materials: iii. HHA Steel, approximately 500 BHN through-hardened. Approximately twice as effective as RHA against KE and HEAT on a per-weight basis. Not weldable, middling shock properties. Available in thicknesses up to 25mm. Density- 7.8g/cm^3. iv. Glass textolite Mass efficiency vs RHA of 2.2 vs CE, 1.64 vs KE. Thickness efficiency vs RHA of 0.52 vs CE, 0.39 vs KE. Density- 1.85 g/cm^3 (approximately ¼ of steel). Non-structural. v. Fused silica Mass efficiency vs RHA of 3.5 vs CE, 1 vs KE. Thickness efficiency vs RHA of 1 vs CE, 0.28 vs KE. Density-2.2g/cm^3 (approximately 1/3.5 of steel). Non-structural, requires confinement (being in a metal box) to work. vi. Fuel Mass efficiency vs RHA of 1.3 vs CE, 1 vs KE. Thickness efficiency vs RHA of 0.14 vs CE, 0.1 vs KE. Density-0.82g/cm^3. vii. Assorted stowage/systems Mass efficiency vs RHA- 1 vs CE, 0.8 vs KE. viii. Spaced armor Requires a face of at least 25mm LOS vs CE, and at least 50mm LOS vs KE. Reduces penetration by a factor of 1.1 vs CE or 1.05 vs KE for every 10 cm air gap. Spaced armor rules only apply after any standoff surplus to the requirements of a reactive cassette. Reactive armor materials: ix. ERA-light A sandwich of 3mm/3mm/3mm steel-explodium-steel. Requires mounting brackets of approximately 10-30% cassette weight. Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects). x. ERA-heavy A sandwich of 15mm steel/3mm explodium/9mm steel. Requires mounting brackets of approximately 10-30% cassette weight. Must be spaced at least 3 sandwich thicknesses away from any other armor elements to allow full functionality. 81% coverage (edge effects). xi. NERA-light A sandwich of 6mm steel/6mm rubber/ 6mm steel. Requires mounting brackets of approximately 10-30% cassette weight. Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage. xii. NERA-heavy A sandwich of 30mm steel/6m rubber/18mm steel. Requires mounting brackets of approximately 10-30% cassette weight. Must be spaced at least 1 sandwich thickness away from any other armor elements to allow full functionality. 95% coverage. The details of how to calculate armor effectiveness will be detailed in Appendix 1. b. Firepower i. 2A46 equivalent tech- pressure limits, semi-combustible cases, recoil mechanisms and so on are at an equivalent level to that of the USSR in the year 1960. ii. Limited APFSDS (L:D 15:1)- Spindle sabots or bourelleted sabots, see for example the Soviet BM-20 100mm APFSDS. iii. Limited tungsten (no more than 100g per shot) iv. Californian shaped charge technology- 5 CD penetration for high-pressure resistant HEAT, 6 CD for low pressure/ precision formed HEAT. v. The general issue GPMG for the People’s Auditory Forces is the PKM. The standard HMG is the DShK. c. Mobility i. Engines tech level: 1. MB 838 (830 HP) 2. AVDS-1790-5A (908 HP) 3. Kharkov 5TD (600 HP) ii. Power density should be based on the above engines. Dimensions are available online, pay attention to cooling of 1 and 3 (water cooled). iii. Power output broadly scales with volume, as does weight. Trying to extract more power from the same size may come at the cost of reliability (and in the case of the 5TD, it isn’t all that reliable in the first place). iv. There is nothing inherently wrong with opposed piston or 2-stroke engines if done right. d. Electronics i. LRFs- unavailable ii. Thermals-unavailable iii. I^2- limited 3. Operational Requirements. The requirements are detailed in the appended spreadsheet. 4. Submission protocols. Submission protocols and methods will be established in a follow-on post, nearer to the relevant time. Appendix 1- armor calculation Appendix 2- operational requirements Good luck, and may Hubbard guide your way to enlightenment!
  42. 9 points
    EnsignExpendable

    Books About Tanks

    I like books about tanks so much that I even wrote one myself. https://www.mortonsbooks.co.uk/product/view/productCode/15014
  43. 9 points
    So, recently I stumbled upon something fairly interesting. Most of the people here know about shaped charges and how they work, the principles behind it are fairly well known. Recently however, there has been research about a new 'class' of shaped charges: Reactive Liner Shaped Charges. As the name implies it's a shaped charge with a liner made out of a reactive material. Please note that I still do not fully understand the workings of Reactive Liner Shaped Charges, this post may be changed or updated depending on new information and/or discussions. What is a reactive material, you say? One of the papers explains it like this: (Demolition Mechanism and Behavior of Shaped Chargewith Reactive Liner, Jianguang Xiao et al., 2016) In simple terms, it's a material that only explodes when you hit it really really really really hard with a hammer. Or when you fire it into a solid material at several kilometers per second. I dunno. It's one of the two. What this amounts to is a shaped charge which forms an exploding jet. Neato. But... why should you care? We already don't fire explosives at an armoured target because it's not very efficient, so why suddenly care now? To answer that I have to compare it to normal shaped charges and explain a few things about explosives. The most important thing to understand is that no explosive detonates instantly, there is always a slight delay. This delay is (almost) negligible at normal projectile velocities, but become important at high velocities. Think hypersonic velocities, like with... shaped charge jets! The main thing I am not completely sure about is whether the detonation of the shaped charge initiates the liner, or the impact with the target. The self-delay of the reactive material used in most of the tests is ~0.85 and depending on the liner angle the jet can move 2.8 to 5.2 meters before actually exploding. Of course this distance will be a lot less when penetrating because the material slows down. A reactive material with a too low self-delay might detonate during the formation of the jet, or before it actually managed to penetrate the armour (but this only applies in the situation where the reactive liner is initiated by the shaped charge). This is of course not something you want, you want the liner to detonate inside the target to do the maximum amount of damage. And that's the main reason you should care about shaped charges with reactive liners. They do a fuckton of damage. This is your brain: This is the result of a shaped charge with an aluminium liner: This is your brain on drugs: This is the result of a shaped charge with a reactive liner: To give a sense of scale, that's a 1520 by 1520 mm concrete cylinder. The shaped charge had a diameter of... 81 mm. As you can see the reactive liner does a fuckton more damage compared to a normal liner, this is because the jet literally detonates when it's inside the armour. Concrete is one of the materials that cannot deal with certain forces, which makes it weak versus explosives detonating inside of it. Steel for example cares a lot less about it, but even steel will suffer more damage from a reactive liner than a normal copper liner. The entry hole for a reactive liner is around 0.65 CD whereas for a copper liner it is 0.5 CD. A paper also states the following: The paper however does not show or describe the "tremendous increase in steel target damage". It does however give some basic information and show photos of the entry holes: The penetration capabilities of reactive liners in steel targets were "sacrificed slightly" compared to copper liners, but the paper does not elaborate any further. Here's some more information and pictures about the effectiveness of reactive liners against concrete targets, just for shits and giggles: A 'Bam Bam' is the same warhead as the 81mm one (1.8 kg) from the first photos, except scaled to 18.1 kg. The 81mm charge is called Barnie, by the way. The target is the same ~1500 mm too. As you can see the Bam Bam charge is capable of fucking up massive parts of asphalt roads/runways. A 21.6 cm shaped charge completely destroying around 42 square meters of asphalt. But hey, a 21.6 cm charge is fucking massive, lets tone it down slightly. Charges: Test setup: Results: Sadly there's a bunch of information missing in the tables. It is highly likely that different liner thicknesses were used, but these aren't given in the tables. Results can be found in the full version of Table 1: ...that's around 9-10 square meters of concrete fucked up by a ~1 kg warhead. That's fucking insane. Some other things to note is that due to the materials used in these tests (an aluminium-polymer mix) the jet velocity is significantly higher and the jet length longer than comparable copper liners: So the reactive liner used (26% Al, 74% Teflon) has a jet tip velocity that's around twice as high for shallow charges, but drops to around 1.6 at higher angles. The difference in jet tip velocity is most likely due to the lower density of the reactive liner. This is what Wang et al. said about this: This poor ductility also increases the probability of fragmentation (jet break-up), which can be seen here: So because the reactive liner has a lower density, it forms a jet quicker, but because of its poor ductility it starts to break up very quickly. Tests have shown that a stand-off that's longer than 2 CD is undesirable, whereas normal liners do not really care about a longer stand-off. However! The research done to make the Barnie warhead show that it is undesirable to have cavitation during the formation of the jet. This cavitation is visible in the above simulations, but can better be seen in this one: It is very well possible that Wang et al. had a sub-optimal liner design, since the final Barnie jet looks like this compared to a comparable aluminium liner jet: They are quite similar and the Barnie jet does not have the 'blobs' visible in the simulations from Wang et al.. And last but certainly not least, Xiao et al. calculated the TNT equivalence (RE factor) of the reactive liner: In simple terms, the kaboom-effectiveness of this reactive material is 3.4 to 7.7 times as high as TNT. But since these values on their own are kind of meaningless, lets compare them to other RE factors! The RE factor of C4 is 1.34. The RE factor of RDX is 1.6. PETN? 1.66. Torpex? 1.3. Amatol? 1.1. ANFO? 0.74. The explosive with the highest detonation velocity (Octanitrocubane)? 2.38. THIS FUCKING ALUMINIUM/TEFLON MIX!? MOTHERFUCKING 7.77. Interestingly the theoretical energy contained in the aluminium/teflon mix is only about 4 times as high as TNT. The higher values are most likely due to the addition of kinetic effects. So yeah... huzzah for reactive liners. I might add some stuff to this post later, depending on whether or not I forgot something.
  44. 9 points
    Laviduce

    French flair

    AMX Leclerc Series 1 Special Armor distribution in the hull and turret (not including the spaced heavy side skirts). Once the model is complete i will use it to do some vulnerability modelling along the lines the data presented in the Swedish Tank Trial diagrams:
  45. 9 points
    SH_MM

    Contemporary Western Tank Rumble!

    I don't think there is a possible explanation, because people are beginning the argument from the wrong direction. People are making assumptions about the protection level, then try to find sources supporting it - i.e. first comes the thesis, then sources are searched to support it. That's the wrong way to start research - saying "the Challenger 1 needs to have 500 mm RHAe against KE" and then gathering all sources that say somewhat related. I can understand that Laviduce expects a high level of protection based on the thickness of the Chieftain's Stillbrew armor package and based on the greater weight of the Challenger 1 MBT - it could have a protection level of 500 mm vs KE. But we have no confirmation to these theories. With British documents showing that the estimated penetration of 125 mm tungsten-cored APFSDS ammunition was only 475 mm at point blank, I have serious doubts that a protection level of 500 mm or more against APFSDS was required - that's simply not how tanks are designed. The Challenger 1 development was pursued at a different timeframe than the Chieftain upgrade with Stillbrew armor, thus the requirements were different; in so far "just" 400-450 mm vs KE might be a lot more realistic based on the requirements for the MBT-80 project and the data of the Shir 2, assuming the armor package was improved over the latter tank. The Challenger 1 was approved in 1980, the Stillbrew upgrade in 1984. A lot can happen in four years of the Cold War. Even the Chieftain with Stillbrew doesn't reach protection comparable to 500 mm rolled armor steel vs APFSDS ammo, because cast steel provides up to 20% less protection than rolled armor steel. Ceramic armor is not a magical solution to all problems. The T-64A used ceramic armor, yet it protection level was rather limited compared to later tanks. This is wrong. The cited book - at least in its original German version - does not say what is claimed in the first paragraph of this screenshot of "Armor Basics". While the first quote can be found pretty much verbatim on page 76, the second part - i.e. "the ballistic effectiveness of the compouned armors against KE penetrators shows an improvement of only 1.2 to 1.4 over homogeneous rolled steel plate (incontrast to a factor of 2 against shaped charges." - cannot be found on page 76 or 77 of the original book. I have never read the translated version, but I am fairly certain that it doesn't say what is claimed previously. On page 75, the claimed efficiency values (1.2 to 1.4 vs KE, 2 vs shaped charge) can be found: but that is in a paragraph on the armor protection of the T-72! The "factor 2 against shaped charges" is meant to be the mass-efficiency value and is based on a Swiss assessement from a 1982 issue of the Allgemeine Schweizerische Militärzeitschrift claiming that the T-72's hull armor is weight equivalent to a 120 mm steel plate sloped at 70° and provides twice as much protection against shaped charge ammunition as steel armor of the same weight. The same article also includes statements about the supposed performance of the T-72's armor against KE ammo: the article claims that the T-72, M1 Abrams and Leopard 2 use special armor and certain types of special reach a efficiency against KE ammunition of 1.2 to 1.4 per thickness (!). The T-72, which was believed by the Swiss authors to feature a 300 mm line-of-sight thick array of such armor (in reality it had a simple cast steel turret with a thickness of up to 500 mm, while the hull armor has an effective thickness of 547 mm), would then reach a protection level of 360 to 420 mm. We know for fact that the T-72's armor neither reaches a mass efficiency of 2 against shaped charges nor that it provides a thickness efficiency of 1.2 to 1.4 agianst kinetic energy ammunition. It is a false assumption based on incorrect data from a time when the T-72 was still a mystery to NATO and non-aligned countries. Everything else - regarding the effectiveness of ceramic armor - is not related to the Challenger 1. It is pure, unreferenced speculation that the tank would be fitted with such armor, even though it has been proven that Chobham is (mostly) based on spaced NERA sandwiches. Based on a number of declassified documents on the development of Chobham armor, there apparently were more than a dozen different Chobham armor arrays being tested in the early 1970s. Some of them were merely improved versions of earlier designs, others were created to experiment with new concepts (e.g. there was on Chobham armor array that incorporated high explosives similiar to integrated ERA). There might have been some Chobham arrays with ceramic component in them and this development might have lead to the array adopted on the Challenger 1 - but there is no proof for this; even if they are included, ceramics would only play a minor role. CeramTec ETEC, one of the market leaders in Europe for manufacturing ballistic ceramic materials, includes photographs of the Leopard 2 in its flyers, suggesting that some ceramic elements might be part of the armor array. However suggesting that the Shir 2's 325 mm steel-equivalent protection against APFSDS rounds could be increased to 500+ mm just by incorporating ceramic materials seems wrong. Burlington and Chobham are different names for the same thing - there are numerous files using both names to refer to the same armor arrays. According to the British DSTL, modern armor arrays designed to provide protection against KE and HEAT rounds follow a three-stage layout, i.e. they consist of: a distrupting stage to break KE pentrators and shaped chage jets a distrubing stage, which makes sure that the particles and fragments of the broken penetrator change direction and yaw angle an absorbing stage, which stops the fragments from reaching the interior and absorbs the kinetic energy The options for designing the second stage are pretty much limited to different types of spaced multi-layer armor or other types of reactive armor; based on known armor arrays - such as the T-72B's armor and the M1 Abrams' armor, the distrubing stage usually takes up at least half the available armor volume. The first stage is often based on a reactive armor (see the wedge-shaped armor of the Leopard 2A5 or the Kontakt-5 ERA on late Soviet MBTs), although it could also be made using high-hardness steel, perforated armor or ceramic plates (the latter two variants being common on lighter vehicles, because this armor is more efficient against short, bullet-shaped penetrators). The absorbing stage also can include ceramic materials, but will always include a steel layer (which serves as strucutral support) and potentially kevlar, polymers or other materials. In case of the M1 Abrams, the absorbing stage of the hull armor was a rather simple steel plate. So simply adding ceramics to the armor won't drastically change the protection. The Challenger 1 would require a completely different armor array, which would suffer from the typical problems of ceramic armor against large calibre ammunition, such as a relatively low efficiency, low multi-hit capabilty and problems with cost and manufacturing. Armor consisting of layered aluminium oxide with polymer backing and steel enclosure provides the same protection against shaped charges as steel of the same thickness - thus a Challenger 1 with 700-800 mm frontal armor at most would be quite vulnerable to shaped charges. The "Armor Basics" document from which these snipplets are taken is known to be outdated and incorrect in various aspects. The author speculated too much and used false premises to generate his values - armor thickness, armor weight and layout are often wrong. Here for example he ignored that the Challenger 1 turret is meant to provide protection along a 60° frontal arc (30° to each side of the turret centerline), but the Chieftain was designed with protection along a 45° arc only! Thus his whole idea of using the weight difference to scale the equivalent armor weight of the frontal armor is incorrect. He also claims that a 15% increase in steel mass would result in a steel mass equivalent to a thickness of 50 cm - this would mean that in his beliefs the Chieftain was having an armor thickness of 434 mm, which it does not have in reality - the thickness of the frontal turret armor of a Chieftain is about 240-280 mm according to sources posted earlier in this topic. I don't know any "Ed Francis" and see no reason why his writing should be relevant to this discussion. Seeing that the origin of this quote is a post on the Warthunder forum, which wasn't even written by him, but somebody claiming to have spoken to him, I would be rather careful. This is a big pile of unreferenced claims, that in some cases is rather easy to disprove. It is all speculation with no sources. If Burlington and Chobham were two different things, why would official US and UK documents use both names like synonyms? There are dozens of documents on the development of Chobham/Burlington armor, which are using both names; they also use "Chobham spaced armour" and similar terms disproving the claims that supposedly were made by Ed Francis. And this is how the Chobham spaced armor is shown in the same document - no trace of ceramics! Ceramics themselves do not bulge, but rather break; the elasitic backing behind the ceramic tiles will bulge. Ceramics are not suited for NERA sandwiches as long as multi-hit capability matters, Even if this forum poster had asked Ed Francis on the topic and he let him type on the Warthunder forum with his account, I don't see why this name would result in the text being relevant to us. According to a quick google search Mr. Francis is a volunteer at Bovington, not an expert on AFV design and armor technology. Given that there seems to be no special credentials to his name and that Bovington still has a plaque citing incorrect armor values in front of the Chieftain tank, I do not consider this to be a source. There are no exact figures, which is also related to the problem of "irrecoverably lost" being a philosophical question. However the Abrams supposedly did perform very well in ODS. There were 14 Abrams tanks with DU contamination after being struck by DU rounds or on-board fire, for which the US Army lacked procedures and equipment to deal with. If they recovered these later or not is unknown to me.
  46. 9 points
    Jagdika

    WWII Japanese Tanks in China

    All photos were taken by myself in year 2016 during my visit to Beijing. Tanks are from the Military Museum of the Chinese People's Revolution and the Tank Museum(currently closed). Enjoy. No.1: Type 94 Light armored car (Tankette) in the Tank Museum This is the early version of the Type 94 Tankette. It was found in a river in 1970s. It is the best preserved Type 94 Tankette in the world. No.2: Type 97 Medium Tank in the Tank Museum This is a late version Type 97 medium tank. It carries the old small 57mm gun turret but has the revised engine ventilation port. This tank was donated by the Soviet 7th mechanized division before they withdrew from China in 1955. No.3: Type 97 Medium Tank Kai in the Military Museum of the Chinese People's Revolution This Type 97 Medium Tank Kai's combat serial number is 102. It belonged to the former China North-East tank regiment. It took part in the attack of Jinzhou against KMT army on 1948-9-14, and did great contribution for knocking out their bunkers and MG nests by shooting and ramming. Thus after the battle this tank was awarded with an honored name:"The Hero(功臣号)“ About the tank itself, it was assembled by the Chinese army themselves by using destroyed or damaged Chi-Ha parts after the surrender of Japan. This particular tank was built up with a normal Type 97's chassis(57mm gun version) early model, and a Type 97 Kai's Shinhoto(New turret for the 47mm gun). However there are other saying claim that this tank was modified by the Japanese. It was the first tank that roared over the Tiananmen Square during the Founding Ceremony of China on 1949-10-1. The same tank on 1949-10-1. China's tank army origins from old IJA tanks. No.4: Type 97 Medium Tank in the Military Museum of the Chinese People's Revolution Sorry, only one photo was taken. This Type 97 Medium Tank has a chassis from Type 97 Medium Tank Kai and a turret from a normal Type 97 Medium Tank. It was merged together by the Chinese army. No.5: Type 95 Armored Track(Train track) Vehicle in the Military Museum of the Chinese People's Revolution Only two samples survived. One is in China here and one is in Kubinka, Russia (Maybe now it is transfered to the Patriot Park? I don't know). Hope you enjoy the photos I took! No repost to other places without my permission.
  47. 9 points
    It's a very very long story so just a quick summary for now...got no time these days unfortunately 1. Daigensui(or Sumeragi; 스메라기) first appeared on Korean WOT forum 2 years ago. He introduced himself as a Korean-Japanese woman currently living in Canada and working as a consultator for WOT Japanese tank tree. Then he quickly succeeded in forming a group of fanboys, but not everyone liked him as his fanboys were somehow ruining the forum, and himself was problematic. 2. On June 7th 2014 some WOT players casted doubt on Sumeragi's gender. #Link1 #Link2 3. Then one of the forum members uploaded a series of evidences indicating that Daigensui is not a female, but actually an ex-marine named Kang Seung Jae(this part needs verification as some sources says that he was never a conscript). Other evidences also claim that Sumeragi is a male and banned from numerous forums for his lies, 4. That night the forum administrator(롤랑) invited Sumeragi to a private chat. Admin gave Sumeragi a time to defend himself, but the admin couldn't hear any repliy. 5. During the same period Korean Wargame RD players were complaining about M18 hellcat, which was never used by the ROK army. Then someone found out that it was Sumeragi's fault, and annoyed WRD players joined bashing him. 6. Sumeragi sent his explanations to the admin. #Link1 #Link2 Majority of the Korean WOT and WRD players concluded that Sumeragi's explanations aren't credible enough. 7. Admin made a phone call with Sumeragi. Phone number was from Vancouver, but "her" voice was definitely male's. So now he's kicked from Korean WOT and WRD forums, but that retard currently using a sockpuppet account according to the admin. p.s. He's also famous for pseudologia in other Korean gaming forums. According to Daigensui, he's... * a twenty-something female residing in Vancouver * a lesbian but engaged with "her" cousin * a smartass that graduated both Tokyo and Yonsei university * working in a major company owned by "her" relatives * so wealthy that he can invest $10million rightaway * a distant relative of current Japanese emperor
  48. 9 points
    Holy... What the.. It's fallshirmjager Otto Von Meatbunker, the bipedal sandbag! Use him for cover! Advance on our enemy using his considerable bulk as a shield! Really, does a Ju52 even have a way to carry external stores that large? Cause I cannot see Gefreiter Lardbody fitting through the troop door without using considerable amounts of butter.. And I'm assuming that's a reproduction uniform smock, something has me doubting the Germans ever made one like that in size "Hamplanet".
  49. 9 points
    Collimatrix

    Collimatrix's Terrible Music Thread

    Oh yeah, I can see Gwar doing a really superb live show. Out of respect for the next artist's litigious tendencies towards youtube videos, I will not be posting any audio/visual material. In the 1970s there was a terrible threat to civilization and apple pie and freedom and life itself. No, I'm not talking about punk rock or disco or Jimmy Carter's presidency, although those were all terrible mistakes. I am of course referring to that great rainbow scourge, the gays. The 1969 Stonewall riots began the campaign of gay imperialism. Things that had been safely heterosexual suddenly, overnight, became gay. The color purple. The word "gay." Song and dance numbers. Nazi uniforms. Tight pants. Dressing well. Reading books. By the end of the decade, only men with disgusting walrus mustaches, poor personal hygiene and no words in their vocabulary over four syllables long were safely straight, and the gays were coming for the mustaches too. Breeders were in retreat, and given that the gays had claimed grooming as part of their lebensraum, attracting a mate was getting pretty difficult. The entire globe would be partitioned between celibate, culture-less morlocks and an expanding army of flouncing, hard-bodied interior decorators. This is how the world ends; not with a bang, but a... a sound that is like a whimper, but gayer. But then in the 1980s, God stopped the gays in their tracks. The Moral Majority interpreted AIDS as God's judgment against the gays, but you shouldn't listen to them because they're retarded. God's instrument against the gays in the 1980s was Prince. Yes; Prince, who's early hits included "1999" and "Little Red Corvette," was in fact the defender of heterosexuality who allowed the next generation to be born (that generation would turn out to be the Millennials, but that's hardly his fault). Yes, the man wore a lot of purple and lace, which at first glance seems dubious, but you've got to understand that he was making those things straight again. Yes; Prince was the leader of the heterosexual reconquista. Let that sink in; without Prince, straight people would have been wiped out by the mid 1990's. Yes, the guy is a weirdo and a vegan, but I think that's entirely permissible in light of the fact that he saved humanity from extinction.
  50. 9 points
    Let's all take a trip back to the late 1970s and early 1980s. This was the time of punk. This was the time of despair. Punk was all about minimalism; strip everything down to a few chords, wear clothes you fished out of a garbage can or made yourself and infect yourself with parasitic worms so that when you vomited on some other asshole in a fight, they got parasitic worms too. It wasn't pretty, but it was cheap and it worked. Punk was about to hit pistol design in a big way. The aglockalypse was just around the corner. The glock is the practical application of punk to the art of small arms design. It's reminiscent of John Browning's early striker-fired design prototypes for the hi-power, only made out of plastic and missing half the parts. Not pretty, but cheap and it sure does work. The world was very different in the punk era. Remember that in the United States, violent crime increased dramatically in the late 1960s. In the 1970s they were still figuring out what to do about that. They hadn't had a few decades for the idea that gunfights were just something that might happen day to day to sink in, so the art of practical handgun usage was in a pretty sorry state. Or rather, practical handgun knowledge was in a hilariously bad state at the time. I read through a police marksmanship manual from the late 1960s or early 1970s; it's like an infantry tactics manual written pre-WWI. It's heartbreakingly naive because they hadn't seriously had to seriously think about the problem before then. They had come from a more peaceful world, and were still getting their bearings in the grimdark of the 20th century. This police marksmanship manual still taught the FBI crouch. The FBI crouch is a sort of distillation of the WWII-vintage Fairbairn-Sykes theory of gunfighting, which emphasized speed over accuracy. The idea behind the FBI crouch is that you crouch down so that you're harder to hit, and you sort of get your dominant arm that's holding the weapon into a repeatable, ergonomically neutral alignment with the rest of your body so that you can aim with your entire body. As you can see, this isn't a shooting stance that allows you to use the pistol's sights. In some variants of the stance, you cross your left forearm over your torso so that incoming bullets have that much more flesh to go through before they start hitting your vital organs. Basically, it's the sort of theory of how to gunfighting that you might come up with in a society that, until recently, hasn't been doing a whole lot of gunfighting. Everything was in a more primitive state than it is now. Nowadays you can go into a gunstore and have dozens of brands and styles of pistol ammunition to chose from; hollowpoints of all descriptions line the shelves, each promising to kill people more dead than the next one. Oh, and you can buy full metal jacket if you need something cheap for practice. Back then, full metal jacket was the fancy stuff; the most common ammo was cast lead. Also, cops weren't totally sold on automatic pistols until about halfway through the '70s, they still mostly used revolvers. Also, almost nobody owned a handgun. It was considered weird. Owning a rifle or a shotgun was perfectly normal; what else are you going to go hunting with? Owning a handgun was weird because handguns are for shooting people, and why are you even thinking about shooting at people you weirdo? The laws and court precedent for self-defense cases were a lot different then too. Formerly peaceful society, still coming to grips with the grimdark. So, secret about Beretta; they basically want to make hunting shotguns and make up-scale hunting apparel. They can't design automatic firearms actions to save their lives. Whenever they have to make something automatic they rely on Germans to design the things for them. The AR-70, for instance, was originally a joint design effort with SIG (SIG's evolved into the SIG-540/550 series). The ARX-160 was designed by Ulrich Zedrosser, who, as you might surmise from his name is not Italian. The Beretta 92 is the last in a line of Beretta pistols that started off basically as clones of the Walther P-38. You can imagine it; Beretta in the 1970s doesn't really know what makes an automatic pistol a superior combat piece, although they've been making clones of the Walther action long enough that they can make them work very well. Cops don't know how to gunfight either; all they know is that these automatics seems a whole lot easier to shoot yourself with than revolvers, so they're going to need some sort of super-duper double safety device. Some want double action with a decocker, some want a safety as well, someone want a combined safety decocker... So Beretta shrugs their shoulders and tries to please all these cop agencies. Obviously, they're mainly going to be selling these things to cops and military and a very small number of weirdos. Meanwhile, Jeff Cooper, Jack Weaver and a small but growing number of practical pistol competition shooters are figuring out how to actually fight with a handgun. Meanwhile, in Austria, long-standing armament maker Steyr is about to get a nasty surprise when the Austrian Army holds a competition for their next pistol.
×
×
  • Create New...