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May 26, 2013

Ensign's Q&A Answers #5

By EnsignExpendable

Long time readers should know how this works, but for those just joining us, send me questions to, and I will answer them! Previous edition is found here.

Q: I saw this thing in Nasledniki Tritsat'chetverki (Descendants of the T-34). What is it?
Caption: T-34 tank project, with three guns in the turret (one 76 mm and two 45 mm). December 1941. CAMD.
After evacuation, factory #183 was ordered to produce a T-34 with multiple guns, like the KV-7. Morozov, seeing multiple gunned platforms as a complete failure, designed a project so awful, it was bound to fail. Theoretically, three people were supposed to fit into that turret, as well as 14 76 mm shells and 44 45 mm shells (90 76 mm and 204 45mm shells in total). Due to this crampedness, the turret could not rotate more than 25 degrees to the right, or it would cut the loader in half. Senior military representative at factory #183 Kozyrev writes on December 21st, 1941: "The construction bureau finished work given by People's Commissar Malyshev: powerful flamethrower tank with a 900 liter tank and a 45 mm gun...and mount with an F-34 with two 45 mm guns. The goal of the first development is clear. The goal of the second (T-34-3) is not."

Just as the multi-gun platform rivaled the KV-7 in Chelyabinsk, the flamethrower T-34 rivaled the KV-8. All the resources were dedicated to the flamethrower tanks, and the multi-gun nonsense went away. However, one good thing came from it. The weird asymmetric turret eventually became the roomier model 1942 turret.

Q: Would the ZiS-S-53 fit into the T-43's first turret? I recall that one of the reasons the cupola was moved from the center to the side was because the 85 mm gun's recoil mechanism did not allow the commander to sit there.
A: The T-34 "second variant" with the commander's cupola to the side was developed with a 76 mm gun, so the 85 mm gun's recoil length could not be the reason. But, let's see if it would fit. The recoil length of the ZiS-S-53 was 330 mm. The recoil length of the F-34 was actually larger: 390 mm. My books don't give the exact length, but by measuring the diagrams, the breech to recoil mechanism length of the ZiS-S-53 is 84% of the same length for the F-34. So the gun could have fit without castrating the commander with every shot.

One other thing is the turret ring size. The turret ring on the second variant was enlarged from 1420 mm to 1600 mm. The 1420 mm turret ring was tested with an 85 mm gun on it, but I don't know what the results of those tests were.

Q: Were there any tank destroyers on the KV chassis?
A: Sure, loads. The KV-7, U-18, U-19, ZIK-20, SU-203, to start. Yuri Pasholok is writing a whole book on them. If you expand "KV chassis" to encompass the KV-1S, then you also get the SU-152.

Q: SerB said he wanted to implement the Object 167M hull with the 122mm D-83 for T-62A,do you have any data on the hull or the gun?A: SerB said he's preventing himself from implementing the Object 167 with the D-83 :) But sure, let's take a look at the data.

The Object 167 project was an attempt to make the T-62 more mobile, by means of a new suspension and better engine. The new 700 hp V-26 would allow it to reach 60 kph. The hull armour was no different, 100 mm at 60 degrees. The D-83 was a 122 mm rifled gun, developed in parallel with the 125 mm D-81 smoothbore. I don't have any more data on the D-83, sadly.

Q: Soviet MBT are well known for having auto loaders, but how early on did Soviet tank designers start to look at tank auto loaders? Any WWII era tanks?A: The T-64 was the first Soviet mass produced tank with a true autoloader mechanism, one that replaced the loader's position entirely. However, the Soviet tendency to want tanks to be as universal as possible led to large calibers being used. Past 85 mm, a manual loading process wouldn't have yielded a very high rate of fire, and the IS-2 was notable for its 1-1.5 RPM on release. The mind behind the KV and IS series, Joseph Kotin, writes: "I had a habit of following tanks to the front lines. I don't ride them into battle, but I examine the aftermath. ... I remember we tested an IS. The shell was heavy, the loaders complained that loading takes too long. I climbed into a tank, tried to lift a shell, and confirmed that it was very heavy. I needed to do something. The [Kirov] factory quickly developed a special mechanism for loading shells into the breech." Kotin's device seems to have been effective. In a letter to the Commissar of Armament Ustinov, concerning re-armament of the IS tank with a 100 mm gun, the engineers wrote "We consider it imperative that the D-25T remain in the IS-2. Latest trials at the ANIOP resulted in a rate of fire of 4-6 rounds per minute".
A mechanical rammer was used in the IS-5 (IS-100), but it caused a problem: a relatively large shell, combined with a high rate of fire, led to lots of gases collecting inside the fighting compartment. A bore evacuator could have been used, but the entire program was deemed unnecessary due to the more than adequate performance of the IS-2 against armour.

Q: What kinds of improvised defensive measures did soviet (and maybe other nationality's) tankers use in battle to defend their tanks ?And what was the expected and actual results of their experiments in the field ?
A: Everyone has heard of the Soviet "mattress armour". It wasn't particularly effective against Panzerfausts. In Soviet tests, even German skirt armour was ineffective against a Panzerfaust at 12 meters, let along mesh armour. Track links were welded on to tanks by all nationalities (there are many photos of German tanks with T-34 track links on them, since they were larger). However, that was not the best idea, since the way of making armour of multiple hardnesses work properly is hard armour, then soft armour, not the other way around.

The Americans also used wooden planks to protect their Shermans against magnetic mines, IIRC.
That's it for this week! There are some very long questions that came in that I will need to do some research to answer, and those will be posted next week. Keep sending those questions in to!


  1. THE USMC used the wooden planks to prevent Japanese magnetic mines from attaching. They also tried a Zimmerite style solution of Gravel and paint.

    The British were about to ship all the captured stocks of Zimmerite out to the CBI for their tanks, but the war ended first.

  2. When historians talk about extra armor in form of spare track parts it always sounds like that was such a bad idea that it actually made the armor perform worse than without anything attached to it. Is that true or does extra armor made of soft steel simply do nothing at all?

    1. It performed better against HEAT and HE due to the added thickness, but worse against AP rounds because the uneven, softer surface allowed the shell to 'catch on' during a glancing hit and dig into the armor... it was as if you increased the normalization XD

    2. That, and also piling a bunch of crap on your tank makes tank riders' jobs much harder, since mounting/dismounting is more complicated.

    3. Lastly there is always the added weight... sometimes.

    4. Actually, there are two more aspects. First, improperly installed "armor" could in fact enhance the penetration power of HEAT shells by detonating them further from the main hull and allowing the superheated metal stream to focus more.
      Second aspect was the fact that the crews with all this crap mounted on the tank BELIEVED it gives them extra protection and had better morale, which was also very important.

  3. 122 mm D-83 rifled gun armor penetration data:
    with APDS (m = 6,5 kg, v0 = 1680 m/s) ammo
    1000 meter: 380 mm/150 mm
    2000 meter: 360 mm/135 mm

    Reference: М. В. Павлов, И. В. Павлов. Отечественные бронированные машины 1945—1965 гг. // Техника и вооружение: вчера, сегодня, завтра. — М.: Техинформ, 2008. — № 8. — С. 54.

    1. Thanks! I don't have very much literature on post-war tanks.

  4. From what I have read, reinforced wire mesh armor actually works and is effective against HEAT warheads of RPGs.
    It's not about "stopping" the rocket, it's about damaging the warhead (the fuse goes in-between the links, then the projectile tries to squeeze itself through the link and gets deformed, so the "shaped charge" loses its shape, so it also loses a good part of its effectiveness. The other scenario is - the fuse itself gets damage and the shell doesn't explode.
    Of course this only works against slower projectiles, and it requires some really tough wire mesh. Pz IV J's was probably enough, soviet weakass wire from matresses - not so much.

    BTW German sideskirts were indeed quite ineffective, unless the projectile impacted at steep angle. In such case the distance was large enough to make the jet stream lose much of its power. Pz IV had only 30mm of side angle - so they were penetrated by Bazookas even at 20 degrees or so (if the fuse ignited that is), against 20-30 degrees hits I think sideskirts could be effective...

    1. Keep in mind that the tests were from very close range. The maximum range of a Panzerfaust is much more than 12 meters, although they were infrequently used at such a distance.

      There was official mesh armour, installed at the factory, not just "weak-ass mattress springs".

  5. Very interesting Article! Keep them coming ;)



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