Ensign’s Q&A 15

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You know how this works, send questions to tankarchives@gmail.com, and I will answer them! The previous edition is available here.

Q: Was the S-54 ever used on the T-34? Could it be mounted in the T-34 model 1942 turret?

A: Yes and yes. The model 1931 76.2 mm AA gun (ZK) from which the S-54 borrows its ballistics was recommended for installation in a tank since 1940, but the performance of the F-34 put those plans on the backburner. When the threat of the Tigers, Panthers, and Ferdinands loomed in 1943, many pre-war improved ballistics projects resurfaced, including the AA gun. As the T-34-85 was already in development, the S-54 was seen as a temporary measure. After trials, it was recommended as an upgrade to all T-34s currently in the field, but shortages of ammunition cut those plans short. In any case, the trials ended on October 19th, and the T-34-85 would be available only a few months later.

The gun was installed in the mass produced T-34 model 1942 turret, with some changes. Due to the longer shell, the position of the loader had to be altered. The tank could also carry less ammunition: 52 shells in the hull, 7 in the turret bay, and 9 on the sides of the turret (5 on one side and 4 on the other).

Q: What was the F-42 107 mm tank gun? How did it compare to the ZiS-6?

A: When the subject of 107 mm tank guns was raised, Grabin suggested the F-42, an existing 107 mm tank gun. Stalin refused, saying that the F-42 was too large. Grabin agreed, and built the more portable ZiS-6. The gun was similar to the F-42, borrowing a number of its features, including the loading assist mechanisms. The muzzle velocity of the ZiS-6 was also a bit higher (800 m/s vs 750 m/s).

Q: The Chinese T-34 has 5 degrees of gun depression, while the Soviet T-34 has 6 degrees. Which is the more correct one?

A:

T-34 mod. 1942 with ZiS-4: -2 degrees
T-34 mod. 1942 with S-54: -4.5 degrees
T-34 mod. 1942 and mod. 1941 with F-34: -5 degrees

The Chinese Type T-34 is more correct. Clearly, Russian Bias is at work here.

Q: If a 76 mm shell and a 100 mm shell with the same penetration hit a tank, which one has a better chance of knocking it out?

A: If the shells penetrate, the chance is more or less equal, especially if it’s an AP-HE shell or something like that. If they don’t, the larger shell is probably going to deal more damage, since it would impact a larger area, and is more likely to hit a weak part of the armour and cause spalling. The bigger shell would also carry more explosives, in the case of HE, and will also deal more damage then.

Of course, this question is very theoretical, and I haven’t read any practical work on the topic.

 

That’s it for this time! Send in more questions to tankarchives@gmail.com.

48 thoughts on “Ensign’s Q&A 15”

  5. I guess the 100mm would keep more of it’s velocity (due to weight) and therefore can wreck more inside the tank while the 85mm might actually bounce inside it [, given AP, not HE projectiles]
    do I miss something there?

    • Depends on what kind of armor one is dealing with. Anecdotes from pacific war say that even 75 mm M3 AP shell goes through a Japanese light tank without bursting charge even triggering. Also, if bursting charge fires, tank shell is no longer intact but rather a cloud of large shrapnel, which won’t leave a tank. To that effect, it’s hard to imagine tank to be habitable after 100 mm burster has gone off inside.

  6. Wait, what.

    The 57mm had a larger breech than the 76ers?

    Also, long exposure time combines terribly with high RoF/low alpha. I shudder to think about how Chinese comrades deal with having bad depression on top of craptastic dispersion on the move.

    • ZiS-4 mounting points were shifted when compared to F-34, so depression went down.
      Early T-34 with 76mm L-11 had 7.5deg depression IIRC.

        • You are right:
          L-11: +30 / -5
          F-34: +26.8, +28, +30, +31.75/ -4.6, -5, -5.5 depending on factory, type of turret and year of production
          S-54 – +26.5 / -4.5
          ZiS-4 (1941 model): +30 / -6
          ZiS-4M (1943 model): +31 / -2

  7. Q: If a 76 mm shell and a 100 mm shell with the same penetration hit a tank, which one has a better chance of knocking it out?
    ____________
    Iirc this is presented in the game also. Quite a few time ago i think i read article on FTR where either SerB or Storm stated that bigger caliber means bigger chance to pen eventough both guns have same penetration.

    • You’re thinking about the overmatch effect I think, and/or the “critical distance” (in which the shell can damage modules) after penetration being a multiplier of the bore size.

      • Nope, i already knew about that(overmatch and shell travel distance within a tank after it penetrates) from FTR and his articles, but this was really specific answer that two guns with same penetration, but different calibers, the one that is bigger caliber has higher chance of penetration. For example 122mm gun on IS and 100mm gun on T44, both have 175 pen but IS’s gun have higher(dunno how much) chance to pen. It really stuck in my mind and i’m pretty sure about it.

        • it has to do with individual shell normalization values. Bigger shells have better normalization, mind that thats not set in stone, more like a rule of thumb.

          • Might be, but i really do remember in one of daily Q&A’s here on FTR that some of the devs said it simply like that. Bigger caliber=higher chance to pen. No other detailed explanations why is it like that.

          • Only if caliber/armour thickness is 2 or higher (at which point, normalisation is multiplied by 1.4x that ratio).

            However, the rule only really matters for derpy guns- for instance, a 60mm plate is only about 140mm effective at 70 degrees (by which point it will ricochet unless 3x overmatched) even with normal 5* normalisation, and the medium-velocity 122s (which 2x overmatch for incrrased normalisation)already have 175 pen…

      • I never said it’s true, i said that i saw quite some time ago, when FTR wasn’t part of wot-news.com in daily Q&A that probably SerB iirc stated that higher caliber guns have better chance to pen. It would be really hard to find it, but i’m 100% sure because there was a shitstorm in comments about it, cause russians have higher caliber at lower tiers while everyone else have smaller etc.

          • I know that there is old FTR, but that would be like finding a needle in the stack of hay….and i am 100% sure he said it like that….and statemenet that higher caliber usually means higher penetration has no sense whatsoever….

      • There’s penetration, and distance shell travels after penetration. The former determines whether you bounce, and is +/- 25% of listed value. The latter is (iirc) 5 * shell caliber, and determines what you hit.

  8. Bigger caliber shell losses less pen over distance, so same pen but bigger caliber shell will lose less pen over distance than smaller caliber.

    • At least, this is how it works in wot.
      And bigger doesn’t it’s better (unless it’s a dick) there is a lot different shells same caliber.

  9. Am I the only one who doesn’t give a shit about these Q/A? It’s just like the Q/A on the WoT forums it’s always as if Russians have asked them and no one else!

  11. Regarding shell caliber. It make sense for the larger caliber to have more pen, even if it has the same muzzle velocity of the smaller shell, as it has more mass so carries more energy.

    In game the larger shells do have better chance of pen over the smaller ones even if they have the same pen. This has to do with modules.

    If the 122mm hits tracks with 300hp it will carry on and try to pen the side armor. If the 100mm with 250 dmg hits the same tracks the tracks will “eat” the shell.

    Try to pen the side armour of the kv1 with the 6lb. It is a nightmare even if theoritically it should be able to pen it.

  12. If you don’t know anything about shell mechanics perhaps you should just stay away from guessing about results?

  13. Pingback: Ensign’s Q&A #16 | For The Record