Belesarius

The FNC and its variants need more love
 

 

 

 

 

 

 

 

Some brief shots of J2Ms on the ground and taking off in the first minute of this video;
 
 
Additional footage (untranslated):
 
 
Brief footage of testing of J2M (very brief appearance at the end) and other captured Japanese aircraft;
 
 
 
 

https://in.reuters.com/article/china-military-carrier-idINKCN1SD0CZ
 
 
Chinas 3rd carrier under construction.  Analysis of sat imagery by CSIS Think tank.
 

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/
 
 

https://seapowermagazine.org/lockheed-develops-rack-to-make-f-35a-c-a-six-shooter/
 
 

Gather round, ye posters of Mechanized!
Recent events have indicated that a refresher course on the posting standards of this forum is needed, and so:
Reminder that SH is primarily, first and foremost, a document-based forum. While there is a gentlemen's agreement kind of deal whereby you are not expected to post your sources with every post you make, it is implicitly assumed that you actually have such sources and that they actually say what you claim they do. Furthermore, it is expected that when requested, you post the relevant sources.
While it is known that not all the information relating to the subjects discussed on this forum is public domain, and that therefore informed speculation is a large part of any debate, it is expected that:
A. your speculation have some basis in reality (which can in turn be backed up with at least circumstantial evidence), and:
B. that it be presented as such.
Here is a very good example of how not to post:
 
You would note that the poster in question is extremely confident in their tone with no indication to the average reader that this is in fact complete bullshit, and has no basis whatsoever for the claims he is making. This is in fact the exact kind of posting that is not desired on this forum.
 
On the other hand, here is a good example of speculation done right:
 
The poster in question clearly explains, by analyzing available imagery and using basic logic, why in fact they have reached their conclusions, and backs it up with references to available literature on the topic. No wild assumptions are fielded as fact, nor are any major claims presented without at the very least circumstantial photographic evidence. And all speculation is presented as such- "a seems to be true", "b seems to be better than c", "I'd say d is the case", and so on. Even a poorly-informed reader can easily distinguish between what is implicitly assumed, what is actually known and what is fresh new (grounded) speculation.
 
For those of you who are new, or just rusty, the posting rules are fairly clear:
Kindly re-familiarize yourselves with the rules.
 
And last but not least, remember that the forum motto is  Referte avt morimini, link or die. Hiding behind sources that cannot be confirmed, that have mysteriously disappeared, or that "you seem to remember" do not count. While nobody is expecting you to have all your sources at hand at any given moment, it is expected that you either post them at the nearest possible convenience or back off the claims which remain unsubstantiated until further notice. Failure to do so is considered poor taste, to say the least. Many posters who are no longer with us did not heed the warnings and therefore chose themselves the "morimini" route.
 
The management thanks you for your voluntary cooperation.

3M89 "Palash"

Only remaining Northrop NM9 has crashed in California.
 
https://www.thedrive.com/the-war-zone/27594/rare-and-historic-northrop-flying-wing-crashes-into-prison-yard-in-california?fbclid=IwAR3C5L7xAM-oVKldzuIn18VzWeODW7yacLxo2NA1Ysx-vaeRGycLSsP7ZAA

Holy crap. Shitposting intensifies.
 

I live in Russia, asshole. I do know what Russian propaganda is, while rednecks like you don't.
 
 
Yes, it's wrong, because this myth is spread by people who know nothing about this tank. I'd rather ask them where did they read about problems with aiming.

Consider the geometry of actual armor without ignoring the LFP.
In addition, the mass of the ammo is almost insignificant (25 kg per round and 40 or so rounds in the hull is 1 ton, vs 2 tons each for the engine and transmission plus fluids).
That's not how tracked vehicles work, at all.
You keep throwing this around without sourcing it. While I get that the Merk 4 is better protected than the previous ones, I'm interested in hearing what the actual professionals have to say.
Also, the Namer shows that when sufficiently motivated even the Izzys can adequately place armor around an AVDS if we ignore the LFP as usual.
The Mark 2D seems to show that the guys in charge disagree about the driver's visibility and armor on that side. On the engine side, continuing the hull line at the hump forwards to the beak instead of having it drop would make room for an armor module in front of the engine. That area is not in the FOV of the driver's central periscope nor in the FOV of the right one, which looks out over the engine deck.
Please don't throw around things like this, they betray just how little you actually know.
Let's compare the AVDS-1790-5A as found in the Merk 1 to the MTU 883 in the Merk 4, shall we?
First, the AVDS:

And then the MTU:

Notice something? The AVDS is nominally approximately 4" longer. But that includes the turbo arrangement, which isn't included in the MTU engine dimensions. Once you include the turbo, the MTU 883 is longer.
But wait, you say, the powerpack isn't only the engine! The Merks have used CD-850 Allsions and RK-304 and RK-325 Renk transmissions!
So let's take a look at those now.
First, the CD-850:

Note that the depth of the transmission, 29", is approximately 730mm.
next, the RK-304:

and finally, the RK-325:
https://www.renk-ag.com/en/products-and-service/products/vehicle-transmissions/rk-325/
Dimensions: 1,910 x 830 x 960mm
that's L*W*H.
So, in fact, the RK-325 as found on the Merk 4 is longer than the transmissions in any previous Merk model, as is the MTU engine.
So yeah, the "significant reduction in length of the powerpack unit" is a simple sign that you don't actually know what you're talking about, care to guess again?
You should know the drill by now. Source this claim.
You're zigzagging from "theres no problem with armoring the front along with the engine, slight weight bias forwards is a good thing" to "need to restore balance by uneven wheel spacing".
Also that's not the only reason for having wheels spaced unevenly, care to guess what the other ones are?
Again you're not bringing your A-game, step it up.
2 has a new powertrain with the Renk RK304 transmission, which necessitated changing the entire engine deck area, exhaust routed into the coolant air exhaust manifold, as well as turret changes like the mortar and special armor slapped on.
The drivetrain of the 2 is closer to that of the 3 than it is to the 1.
Well you'd also expect them to realize that ammo separation is the objectively correct way to go, but I suppose you can't get everything.
Also how exactly would you expect them to realize that the alternative is better when they don't have any experience with rear engine tanks newer than the M60A3, anyway?
Reminder that the Merk 3 has a roof sight.
There's a difference between making something work and it being a good idea which gives you what you actually want.
Red is not russian, even if you can't tell Eastern European accents apart.
What did the big bad Russians do to you anyway?
You're dragging the forum discourse level and SNR waaay the fuck down with your shitposting, cease.
 
Hybrids bring their own host of problems, not least requiring more volume and weight than equivalent mechanical transmissions. Also, why would you go to all the trouble of putting the drive sprockets in the front, if you decouple them from the engine? it's objectively a worse location for them.
This bit we've been over before, and I'm just qouting it again to rub your face in how wrong it is and how you never bothered to perform 10 minutes of googling because you lack any self-critical thinking ability.
You're gonna have to source this too, this claim in particular is interesting, as on the Merk the air filters were never in the way of the UFP in the first place!
Aaaand you're confirmed for never having viewed anything through a camera resting above a hot surface.
That's not only an incredibly asinine statement, considering how the IDF hasn't designed any rear-engine MBTs, but it's nevertheless still wrong:



 
In short, @Mighty_Zuk, you have a lot of unsubstantiated claims to back up, Referte Avt Morimini.
You've also said a lot of bullshit that betrays a basic and fundamental lack of understanding of the subject matter. Git larned, and kindly match the confidence displayed in your posts to your actual level of knowledge in the subject matter, and not to what you'd like others to believe it is. You are invited to step up your game and keep the baseless speculation and denial to other forums like AW, and refrain from overly nationalistic fanboyism.
Also, if you don't know something, even in a field which is close to your heart, just admit it. there's no shame in not knowing shit, but there's quite a lot in pretending to know stuff you don't and being flat out wrong.
Kindly raise the standard of your posting, we really don't want this place devolving into AW or worse, DFI. Which is unfortunately the current posting standard you are representing.
 
Sure, if you like your tanks immobile.
 

While the video is indeed garbage, your rebuttal is as well.
So your counterpoint to "the engine bay being hot and in the front is an issue with the Merk" is "It's more important and therefore it isn't an issue".
If you actually bother to look at how the Merks 1-3 and the AVDS-1790 are put together, you would very quickly notice that the hottest air from the engine is blown straight onto the deck above (which on the Merk 1, 2, and early 3 would appear to only be solid steel, with no give-away bolt heads to indicate composite armor of any kind), and from there out the side louvers, sideways (and slightly back). if it were thrown down it would kick up clouds of dust.
Steel is, of course, an extremely good conductor of heat, and this in turn means that if the lower surface gets hot, well, so too does the upper one. The thickness of this plate is, in fact, mostly irrelevant.
Additionally, if you knew anything about other tanks which use the AVDS, you'd know that the entire purpose of the funky grating on the back of the M60 (and originally the M48A3 with the AVI-1790-8) is to reduce the IR signature. And yet despite that grating and exhaust tunnel design, the M60 retains a non-negligible IR signature. I strongly suggest reading what Hunnicutt has to say on the topic. To assume that the Merks 1-3, which squeeze more power out of what is effectively the same engine and therefore have more waste heat to remove, and have less grating area to permit airflow, somehow end up expelling colder air is plain fantasy.
Unlike the Merk, the M60 spits out its hot exhaust rearwards, out of the line of sight, and therefore the exhaust grills are out of sight from the front. The Merk has its exhaust grills in the front arc of the tank, where they can clearly be seen (and of course the grills heat up to approximately the temperature of the exhaust air). On the Merk 1 it was waaaaay worse, as the engine combustion exhaust was just piped out to the sides and expelled there, resulting in a large patch of the vehicle which get hot enough to fry an egg on. On the later Merks the exhaust was routed to mix with the engine cooling air exhaust, indicating that this was a large enough problem that it needed to be solved.
The later Merk 3 has a layered deck above the engine (if the bolt heads are anything to go by), and layers (particularly if they include air layers) are extremely good insulators, so that bit should be mostly ok now; the Merk 4 has both a layered deck and an MTU engine, in which the air flows the other way through the engine, from the top downwards and out the side. The Merk 4 also what looks like layered sponsons around the exhaust grate, which the 3 lacks; so that area too should be better off than it was. These tanks however also have solid steel hulls, which the engine can and does heat up through its mounting points (as you need pretty solid mounting points to hold down a 1000+HP diesel), and the hull extends forwards to the nose (and to the non-modular sponsons on the Merk 3), giving a large area in the front radiating away. It should also be noted that transmissions produce non-negligible quantities of waste heat, as do the brakes (torque converters too, yay viscous fluid shear), for obvious reasons; more so that the engine if you're doing anything other than standing still. And having those stacked right up close against the steel hull is asking for it to heat up.
 
So yeah, handwaving away the heat from the automotive components being in front as "Not true"
You wouldn't happen to have a single fact to back up that rather bold statement, would you? Like, a source of some kind?
Regarding the pic you posted, there's a certain component that deserves some attention there. Specifically, the tires on the roadwheels. You may note, that they are white and therefore cold. Now, what do we know about roadwheels on tanks?
hint: they ain't cold when the vehicle is moving:

So by the fact that the wheels are cold, we know that the Merk you posted has not been moving, and indeed one cannot tell how long the engine has been running; nor can the LFP, which is by all accounts part of the steel hull, be seen. Using a photo such as that to demonstrate the effect of the engine on the thermal signature is disingenuous at best.
 
The LFP is a thing on the Merk 4 too, you know; and considering how the rest of your treatment of this point is "I'd rather have a damaged engine", you're effectively trying to squirrel out of the fact that yes, the engine on the Merk is more vulnerable than it is on MBTs.
Not if said conventional design had, y'know, armor there, like, I dunno, the Abrams or Leo 2.
Again, do you have a single fact or source to back that opinion up?
And, as usual, you are ignoring a much more vital component than the engine, care to guess what it is and why?
In actual competently designed tanks post-1973 there are no fuel tanks in the crew compartment (excluding derivative designs which inherited them), so that's a bit of a moot point. Most modern tanks keep the fuel in the engine bay and/or the sponsons, and not in the front of the hull where armor belongs.
I find that hard to believe, you wouldn't happen to have a source for that would you?
Cause if we take that at face value, that would make the Merk the first tank designed without armor compromises since what, 1916?
Also the multiple generations of modules and sideskirts spotted on Merks suggests that that is not actually the case.
Of course another point that both you and Red missed is that tank armor is designed to meet a reference threat. What that threat is is a different question, but considering how Egypt, Jordan and Syria all operate tanks which fling APFSDS and which the Merk 4 is at least notionally supposed to be able to go up against and win, the idea that its armor doesn't at least do something against KE is laughable, to say the least. What the CE threat is is also an open question. Red also clearly doesn't get how "special" armors work against CE.
Again, fact to back that up? Cause without a source, that's just meaningless handwaving.
Cause even with the most modern turret modules seen on the Merk 4m, there doesn't seem to be any burster plate to prevent the blast from an ATGM disassembling the armor inside, the way we've all seen the pictures of it happening from 2006. If the declasified Brit Burlington docs are anything to go by, NERA arrays have trash multi-hit ability without burster plates, and there's no reason to believe the Izzys have some super duper sekrit sauce nobody else does to solve this problem.
That's a very strong statement to throw around unsubstantiated. You wouldn't happen to have anything resembling a source to support this claim would you? Official claims that this is indeed the case? Product page on one of IMI's websites that claims this gun ever existed? pictures of a testbed with the gun?
The last time I saw someone taking the claims of a 140mm gun on the Merk 4 seriously was back in the early 2000s, before the thing entered mass production, and even then it was presented as only being rumors and not thrown around as if it were a fact the way you're doing.
Both these claims also need to be sourced.
For reference, L/55 guns have a whole host of problems accompanying them, including balance issues, elevating mass and inertia, recoil impulse and length (same problem faced with more energetic ammo in L/44 guns), and so on. As part of the upgrade to the L/55 in the Leo (part of the A5 upgrade pack), the gun drives were replaced and the entire mantlet area redesigned -the newer mantlet is much narrower, and the gap is filled by armor boxes attached to the fixed turret structure, most likely to reduce the elevating mass and restore margins.
L/55 guns are enough of a headache that the US seems to have decided to not go that route because of the problems the testbeds had with them. Handwaving away integration issues like this as "no biggie" is being deliberately ignorant.
We've already been over the whole thermals business and that picture, but what I don't get is even if we assume you are correct and the Trophy antennae are a stronger radiator in the relevant wavelengths*, how is this greatly increased thermal signature a point in favor of the Merk?
*even with extreme emissivity differences, I don't see how that could be the case. Comparing to a similar radar by the same manufacturer, I get 110W continuous power draw for the radars at most (comparing to the Elta EL/M-2129), as opposed to several hundred KW waste heat in the exhaust even at idle.
A. You are aware that the wonders of modular armor mean that armor packages can be changed mid-batch, and that therefore doesn't make it a 4a/4b difference.
B. If you think minor changes like that (and whatever internal changes to the armor module it covers) are enough to prevent the blast from a warhead shrekking the armor after a hit you're somewhere between deluded and hopeless.
 
Before being a Democrat and blaming Russian propaganda, consider the following:
1. Is it wrong? If it is correct, or at least has a good change of being so, crying "propaganda!" is a great way to discredit your viewpoint.
2. Cui Bono? If the Russians don't stand to benefit (and indeed, what good does mocking the IR signature of an irrelevant third world country's tank does to the Russians), why would they waste their propaganda efforts on it?
Kindly use your brain before posting.
Also kindly try and keep your shitposting on this forum in full grammatically-correct sentences. 

Only remaining Northrop NM9 has crashed in California.
 
https://www.thedrive.com/the-war-zone/27594/rare-and-historic-northrop-flying-wing-crashes-into-prison-yard-in-california?fbclid=IwAR3C5L7xAM-oVKldzuIn18VzWeODW7yacLxo2NA1Ysx-vaeRGycLSsP7ZAA

This one time in the Army (I'm required to start all my army stories this way by my wife)....
 
Well I was a driver on an M60A3 when I was in C Co. 1/70 AR in Germany in 1983. We were driving down this tank trail, the lead tank of our platoon, when this crunchy (infantryman) pops out from behind a tree. He was about 50 meters or so down the tank trail when he holds up his rifle across his body in a "Halt!" fashion. I ask my TC if I should stop & he says to keep on driving. The crunchy motions for us to "Halt" a couple more times in an increasingly more aggressive and desperate fashion. When we get about 10 meters from him he suddenly realizes that we aren't stopping and an M16 isn't going to faze us one bit. He dove one way and his rifle went the other as we rolled on pass him. I said to my TC "I wonder what he wanted?" and my TC replied "Who the fuck knows." It isn't a wonder that there's no love lost between DATs and crunchies.