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Sturgeon's House


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Everything posted by Collimatrix

  1. Collimatrix's Terrible Music Thread

    I just discovered this and it is amazing: They take bad songs and jazz them up until they are good. Or, in some cases, jazz them up until they are merely tolerable:
  2. So, I'm snowbound in a little motel in Rawlins, WY. It's a dinky, creaky old place with no internet, no running water, and it's built on an old Indian burial ground. Anyway, I was thinking about music. I listened to The Pierce's Thirteen Tales of Love and Revenge on the way down here, end to end. Holy crap, this is a superb album. Allison and Catherine Pierce are both excellent singers with some really excellent harmonies (but not so often it gets dull). Instrumentation and melodies are varied too, but not so much it feels thrown together. And wow, the lyrics. The probity of the album's concept is immaculate. It oozes jealousy, loss, lust and toxic sexuality worthy of an opera. A taste:
  3. Alright, we've got documents threads in aerospace and tanks, we need some for small arms now too. Small arms technology lags other fields by decades, by here at Sturgeon's House, it only lags by months! General Design Theory Treatises: First up is a link to George M Chinn's The Machine Gun. This is the premier English-language book on automatic weapon design theory. Also, because it was a US Government publication, it is legally available for free. The book is mainly focused on the design of autocannons, but the theory is applicable to smaller systems as well. If you read this book and understand it, you are ahead of 90% of the people in the industry. Next is this US Army document on small arms design hosted at Forgotten Weapons. The theoretical information in this is largely taken from Chinn, but it adds a lot of notes from experience on what does and does not work. It also has an excellent quantitative discussion of recoil, and some notes on various concepts the US Army was playing with at the time. More Specific Documents: Extractor Lift in the AR-15 series. This interesting series of tests disproves the rationale behind "improved" "lobstertail" AR-15 extractors. In addition, it shows just how much residual blowback pressure there is in the M4 (it's more than you'd think). Why Telescoped Ammunition Sucks. It really sucks. Jim Schatz on caseless ammunition. Very interesting read from a guy who was there when it happened.
  4. Not only that, he was fired two days before he would have earned a pension!
  5. AFV Engines

    There's usually more than one shaft. The AGT-1500, for instance, has two shafts taking power from the high and low pressure turbines to the compressors, and a third, completely separate power turbine with variable inlet geometry that actually delivers the power to the transmission. So the power turbine could be at or near stall but the rest of the engine wouldn't necessarily.
  6. It occurred to me, while reading LoooSeR's account of how a bunch of peasants are clobbering the expensive Saudi military, that perhaps it was time to take a good, hard look at the Kingdom of Saudi Arabia. What a vibrant and wonderful country! Saudi Arabia leads the world in incest: Saudi Clerics have novel theories of science. They have a diversified, modern economy, which is definitely not unstable: Including a booming agricultural sector! What a swell place, with enlightened views on women!
  7. AFV Engines

    His specific argument is that a tank's actual power to weight ratio is not the gross horsepower of the motor divided by the weight of the tank, but rather the sprocket horsepower divided by the weight of the tank. Sprocket horsepower is the gross horsepower of the engine minus losses from the cooling system and the transmission. Since the Merkava mk III is supposed to have a particularly efficient transmission, its actual power to weight ratio isn't as bad as the more simplistic numbers would suggest, and in fact the merk has no worse of a power to weight ratio than tanks that have more powerful engines, but less efficient transmissions. I don't buy it. Here is the full quote from Technology of Tanks concerning the difference between gross horsepower and horsepower available at the sprocket: So the Merkava has a transmission that never dips below 71% (he claims), and it's up against transmissions that are only doing 61% efficiency. That's a 16% improvement in power actually delivered to the sprocket. But so what? A 1500 horsepower engine has 25% more gross horsepower than a 1200 horsepower engine, so a 1500 horsepower engine through a shitty Allison transmission is still going to be putting more ponies into the drive sprocket than a 1200 horsepower engine going through a magical Israeli transmission. The numbers don't add up. It's horseshit. On top of that, in the particular instance of the Abrams vs the Merkava, the Abrams has a higher percentage of gross engine horsepower available as net engine horsepower because turbines are (nearly) self-cooling, and don't loose significant power to radiators or fans.
  8. Aerospace and Ordnance discussion/news.

    There was an attempt to make the Standard into the world's biggest AAM; the AIM-97 Seekbat.
  9. Israeli AFVs

    Did the Arab forces ever get BK-15M ammunition?
  10. Explosive reactive armor is that brick-looking stuff that the Soviets loved covering their tanks in during the last days of the Cold War: Kharkov Stronk! I admit not knowing much about ERA, but a quick check around various sources has impressed the following things on me: -ERA is, pound for pound, the most effective armor technology that exists. Nothing else even comes remotely close. First-generation Israeli Blazer ERA was estimated to have a mass efficiency (vs RHA) of 20-24 vs HEAT threats. That's insane. The very best modern steel laminates using ultra-high hardness alloys magically welded to high toughness alloys achieve a mass efficiency of 1.5. MEs of 3 are spoken of in hushed whispers for exotic material composite arrays. ERA must be mounted on something fairly stout, on account of the whole "explosive" thing, but even mounted to RHA, the ME of the entire array is on the order of 2.5-3.8, and better still for ERA mounted on top of something more sophisticated. ERA is stupidly cheap and stupidly light for how effective it is. -The most commonly available descriptions of how the Kontakt-5 "heavy" ERA works are probably wrong. Surprise surprise; commonly available articles about a technical subject are completely wrong. Robb Mcleod's article gives a more likely explanation on the basis of areal density vs. installation mass and coverage. Instead of an extremely heavy one-piece flyer plate that snaps the APFSDS penetrators, Kontakt-5 works by having two flyer plates that move in different directions; one slightly up and one slightly down, guillotining off the front portion of long-rod APFSDS penetrators.
  11. 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 IT 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.
  12. Unified Naval Documents Thread

    We need one of these. Notes on German super-battleship design Soviet/Russian document dump US WWII Documents US Navy discussion of cage vs tripod masts 60 Years of Marine Nuclear Power (Soviet Union & Russia)
  13. Leading congressional Democrats have released a new plan that they intend to implement if given a majority in 2018. It's... a tax hike. I am certain that this is a brilliant piece of political maneuvering that is guaranteed to win the Dems more votes this fall, because if there is anything Americans love, it's paying taxes. Seriously, what the fuck?
  14. Forum Improvements and Changelog

    March 9, 2018 The tagging continues.
  15. Forum Improvements and Changelog

    I thought I would put this where everyone could see it, since we've finally started doing meaningful changes to the forum, it would be good to document them.
  16. Terror Attacks and Active Shooter Events Thread

    Developing situation at a veteran's home in California.
  17. Just so everyone is on the same page, here is why the L85 should have ended at A1: When an army is looking to improve its equipment, there is a perennial debate between getting a completely new design or upgrading the existing design. A new design usually offers more potential, but an upgraded version of the old design usually has at least some parts commonality with the existing spares pool, some commonality of production with the existing production line, and users will usually be familiar with the old design. Therefore, upgrading the old design is usually the lower cost and lower risk alternative to purchasing an entirely new design. Except with the L85 none of that is true. L85A1 and L85A2 have almost no parts commonality. This is because the L85A1 was a garbage rifle made of garbage parts, and all the parts needed to be replaced. By "all the parts" I mean that the barrel, bolt carrier group, piston, charging handle, trunnion, gas block, hammer, firing pin, bolt hold open and magazine are all new. All of these new parts are color-coded or marked to prevent armorers from installing old parts, both because they are crap and because in some cases they will not interchange. L85A2s are made by un-folding L85A1s, pulling out everything inside, re-folding the receivers (correctly this time), and filling them with a compliment of entirely new parts. So much for being able to re-use the existing pool of spares. The British SA-80 production line was shuttered decades ago. It was not re-opened. There is no savings from re-use of existing tooling. The L85A2 was reverse-engineered from the L85A1, and then made to actually work. The L85A2 does have the same controls as the L85A1, but the controls are crap. The fact that it's the same crap is not a compelling case for keeping them around. L85A3 appears to be a new-built receiver with a new railed handguard and L85A2 parts inside (possibly with some small improvements on those). It's likely that making an L85A3 is cheaper than making an L85A2, since L85A2s were made out of extensively re-manufactured L85A1s, and that remanufacturing process was so involved that it was so involved that it was cheaper to make new guns. So L85A3 is an improvement, but it's still a far less effective solution buying Colt Canada C7s the way the SAS did.
  18. The Great War

    We should have a thread about World War One, even though it's not really something I know that well. I have not been following The Great War on youtube or much else. Here are some cool trench cross sections though.
  19. The Worm Thread

    One thing notable about Worm is that it's a parody/deconstruction of the superhero genre. There are lots of those, some better than others: But it doesn't just point out the absurdity of the genre's conventions, it actually weaves them into threads of a coherent narrative.
  20. Ornithology Updates

    Interesting idea. As far as I can tell, avian salt glands use potassium/sodium ion pumps, which are ubiquitous in higher animals and also used in neuron function. There are potassium/sodium ion pumps in the kidney too, so my guess is that the salt glands are just more efficient at excreting salt per cubic centimeter of organ because they only contain the enzyme for excreting salt, and lack the other enzymes for excreting all the other waste products that kidneys excrete. I don't think that the fundamental biochemical mechanism for excreting salt in the salt glands in particularly more efficient, it's just more concentrated and the organ does not waste energy by supporting any other functions besides salt elimination. The current best technology for mass desalination of water is reverse osmosis, although forward osmosis has some proponents as well. In either case, the technology is getting surprisingly close to the thermodynamic limits for efficiency of the process.
  21. Ornithology Updates

    We'll start this one off with the recent discovery that Australian brown falcons deliberately spread fires in order to flush out prey.
  22. Terror Attacks and Active Shooter Events Thread

    Two Miramar Police Department SWAT Officers Suspended for responding to the Stoneman shooting without orders.