Ensign’s Q&A #10

Let’s take a small break from the seething masses for another Ensign’s Q&A! You can find the previous one here.

Q: What was the historical ROF of the D-25T? Was it with two-piece or one-piece ammunition?

A: The IS-2 was capable of 4-6 RPM. As far as I am aware, tests of one-piece ammunition with the D-25T were only performed on the T-44-122.

Q: How far did nuclear tank projects go? Are there legitimate sources on these projects?

A: As far as Soviet tanks, there weren’t any. The closest thing developed was the TES-3 mobile nuclear generator, designed to deliver power to remote regions.

Q: Why were multi-gun tanks abandoned?

A: Throughout tank-building history, there have been several attempts at multiple guns and multiple turrets. The first such attempt was in infantry support tanks. For example, the Vickers 6-ton (later adopted as the T-26) had a variant with two machine gun turrets. Both of these turrets could operate independently, and cover a sector of the front. When tanks were still few in numbers, and were not likely to meet each other (especially Soviet tanks, whose main enemies at the time were bandit gangs in the Far East), this solution was considered very good. Later, a 37 mm gun was placed in one of the turrets in order to boost the firepower a bit. This tank was not so great at fighting other tanks, since the gun was still low powered, and could not cover 360 degrees due to the other turret being in place. When the time came to upgrade to a 45 mm cannon, the two turrets became one. The same is seen on the Vickers model with the 47 mm gun.
While the effect of 45 mm high explosive shells boosted the tank’s anti-infantry capability, the military wanted more. 3 inch howitzers were common in armies of the day, and many countries decided to equip their tanks with them. However, recoil devices were not quite up to par with the power of these guns, and so they had to be very short. Short guns mean low velocity, low velocity means that these tanks are helpless against other tanks. For tanks like the T-28, this was not much of a problem, since it was intended to fight infantry. In that same vein, it received two machine gun turrets, like the early T-26, since they could now operate independently without interfering with the main gun. However, for the heavy T-35 tank, this was a problem. The tank was meant to break through enemy lines, and defeat tanks and infantry alike. With the lack of a high velocity 76 mm gun, two 45 mm turrets were added.
Less than a decade later, the T-35 was set to be replaced by one of three tanks: the SMK, T-100, or KV. The SMK and T-100 inherited the T-35′s multiple turreted-ness, although now they had a high-velocity 76 mm gun. The KV had both guns in one turret. The SMK lost a turret during development, but, in the end, the verdict was clear: commanding two, or even three, guns was very complicated for the commander. The low caliber guns no longer had any advantage over the high caliber gun. Plus, getting rid of the turret would allow to increase the armour thickness. The KV, with a single 76 mm high velocity gun, won out in that competition.
Throughout the war, multiple guns are seen on one other tank, the Maus. A faster firing 7.5 cm gun is added to defend the tank from infantry, since the main 12.8 cm gun fired exceptionally slowly. Initially on a separate turret, the gun migrated to a coaxial position by the end of the tank’s development life. While reducing the tank’s height, it made it fairly useless. The slow rotation of the turret would mean the gun would be unable to keep up with agile infantry movement.

Now, that’s just for different guns. Having two of the same gun pointed in the same direction was a much more successful tactic. Military history is full of double, triple, or quadruple cannons of various calibers used as AA guns. The Soviets had a prototype SU-122 with two howitzers. Even though it didn’t pan out, its spiritual successor, the Koalitsiya (Coalition) is doing well. There’s also the ST-II tank project, which was quite curious, but died due to the inventor having few friends in the right places and the general declining interest in heavy tanks.


61 thoughts on “Ensign’s Q&A #10

  1. During the Cold War, the NATO states had a bit of a fling with using auto-cannons for coax/secondary guns. Just off the top of my head the Centurion had a Polsten 20mm (which can be seen in-game), early models of the Swiss Panzer 61 had a 20mm coax, the US and Germany intended for the MBT-70 to have a remotely operated (in 1960!) 20mm Hispano-Suiza cupola gun, the final version of the Starship Patton also had the a Hispano-Suiza in the commander’s cupola, and the AMX-30 was upgraded with a 20mm coax after it had been in service for a while.

    • You write this like a remote controlled machine gun is very high tech. Even the Hetzer had a remote controlled MG ;)

    • Not strictly a tank, but the Russian BMP-3 has a 100mm main gun, a 30mm autocannon, and a 7.62mm machinegun all mounted coaxially. Furthermore, the 100mm is capable of functioning as both a low-velocity gun and an ATGM launcher. Now that’s what I call multi-gun!

  2. I love those. As simple as that. I also think that some of my privately-sent questions have been answered here :)

  3. Now I am wondering what is the historical ROF of german 88mm guns? Were the l/56 and l/71 any different concerning this aspect?

    • I found this in a forum post:
      “The rate of fire for the main gun was good, at about 4-6 shells/minute for the KwK36 and about 2-3 shells/minute for the KwK44. [Schneider, Jentz]”

      If that is true, the game is compeltely wrong with its high ROFs ;)
      Maybe the ROF used in the game is measured over one minute while the above numbers are for a whole battle, where the loader gets tired.

      • After thinking about it the numbers really seem to be way too low. I also found this ” 8.45/ minute” for the short 88.
        Maybe SS knows the exact numbers?

        • I also found differences in “normal” loading, “lap” loading and battle loading where ammunition has to be aquired from different ammo storages in the tank so it takes quite some time.

      • Note these nr’s are during combat, which includes aiming time and target acquisitioning, how fast they could fire theoretically im not sure, decent crew probably around 7-8

      • You should also remember that it could take3-8 (extremes of both ends)rounds for the tankers to get the correct range. You have a small sight and are trying to hit a rather small target at very long range.

        That said ROF will depend on how far you have to go to get the shell and how well trained the crew is to work together so that by the time the shell is loaded and the breach locked the gunner can fire nearly instantly.

        I would think that figuring an exact fire would be doable but that figure would be representative only of the first 5-12 shells. after which I would expect the ROF to drop considerably. People do get tired after all even if they have been drilling it for months/years.

    • The 88L/71 in the Tiger II would be different, since the ready rack was prone to detonations, and not used, while the other racks were very inconvenient for the loader.

  4. Q I wanted to ask for some time: How to contact you/send Q’s in private, Ensign?

    And when we are at the questions: Some T-34 were armed with 57mm ZiS guns due to shortage of 76mm guns, correct? My Q: Were there any plans to actually arm the T-34s with 45mm or any other guns due to the lack of the 76mm guns?

    • T-34 were armed with 57mm guns because they’ve had better anti-tank capabilities.
      There were 2 short lines of these tanks being equipped with 57mm gun – in 1941, as a alternative-armament proposition, and in 1943, due to Germans having much more Tiger tanks.
      The number of T-34-57 was small, as Russian staff didn’t considered trading anti-infantry power for anti-tank power as worthy.

    • If you don’t mind, I can answer those questions on his behalf.

      1) Send your questions to EnsignExpendable at tankarchives@gmail.com.

      2) The 57 mm ZiS-4 was developed and mounted on the T-34 in order to improve its anti-tank capability, not because of a shortage of 76 mm guns, and was in fact more expensive and difficult to produce than the 76 mm L-11 and F-34 guns.

      There did exist a proposal for the T-34 to arm it with a 76 mm gun and two 45 mm guns in a turret, but as far as I know, it was not pursued, as it was a pretty dumb idea to begin with. I doubt there were any projects to mount the 45 mm gun on the T-34, as I don’t think there ever was a situation where there were more T-34s available than 76 mm guns, but EE can answer that better than I can.

    • I think those T-34/57 were intended for tank-vs-tank engagements, because the 57 mm had better performance in that area :)

    • As the others have said, the 57mm was considered because it was actually a superior anti-tank weapon to the standard 76mm, and this is reflected in WoT where it is the gun of choice for the T-34. However, it was not adopted widely because the 76mm had a more powerful HE shell for engaging soft targets.

  5. “The IS-2 was capable of 4-6 RPM”

    T-72 Ural (1973.) official data:
    Gun: 125mm (IS-2: 122mm)
    Ammunition: 2 piece (IS-2: 2 piece)
    Ammo weight: 15kg (IS-2: 30kg)
    ROF: 8 (with autoloader), 2 (manually loaded)

    Dude, stop smoking weed. Even hardcore pro-Soviet sites mention ROF of 1.5-2 rounds per minute.

    • You do realise that the autoloader and ammunition layout on the T-72 makes it a lot harder to manually load the 125 mm gun if the autoloader breaks down as compared to the IS-2, which was designed from the start with manual loading in mind, right?

      I don’t see how your comparison is valid.

      • Fine point, but irrelevant.

        But to satisfy your curiosity:

        M1A1 Abrams tank official data:
        Gun: 120mm
        Ammunition: single piece
        Ammo weight: 19kg
        ROF: 6 (manual “semiautomatic” loading)

        So, Abrams can achieve ROF of 6 rounds per minute, with lighter, single piece, quick access ammo with loader in a spacious combat compartment.

    • I don’t get what posting the T-72′s stats is supposed to prove about the IS-2?

      • IS-2 never had autoloader. Last line (ROF) concerns T-72 only. Draw your conclusions from there.

    • Ok, you’re comparing T-72′s gun with the IS-2′s gun.
      You’re saying that they both can load 2 sheels in the autoloader, T-72 ammo having 15KG each and IS-2 ammo having 30 kg each.
      But now you tell me that both have the same reload?
      How comes that?

    • You should at least read the link.

      “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”.

        • *Your* common sense. Which can go take a piss compared to the Soviets clearly finding the performance of the gun perfectly acceptable well into the Cold War.

          • Then why did they bother with developing new guns and other tank technologies when they had “perfectly capable” system decades before?

            IS-2 was woefully inadequate during Cold War, especially compared to MBTs. It was used by those who could not use anything better.

            • IS-2? Who said anything about the IS-2? I was talking about the *gun*, pay attention. And the D-25T was apparently deemed good enough to still serve (with the addition of a bore evacuator) as the initial main gun of the IS-8/T-10, only replaced with the M-62 in the T-10M version from ’57 onwards.

              Also your arguments are idiotic.

  6. What, the US had nuclear-powered tanks but the Soviets did not? Are you telling me that the Soviets were the sane ones for once!?!

  7. I really don’t believe if the rates of fire are consistently measured. What are the standards, methodology and practices for testing rate of fire? One of the most confusing rate of fire examples is very slow reload speed of the Maus, but it has 2 loaders (albeit a useless 75)

    “Latest trials at the ANIOP resulted in a rate of fire of 4-6 rounds per minute”

    How are such trials done?
    Do they fire the gun from a carriage setup or inside an actual tank?
    Do they actually continually shoot for one minute or take 2-3 shots and multiply?
    How did other countries calculate rates of fire measurements and standards differ from each other?

    • I think we can take for granted that “trials” means maximum under ideal conditions. The only question that leaves is whether it was mounted in a stock tank, sitting on a test firing rig, or something in-between.

      I would expect peak ROF to be pretty brief with those shells to lug about.

    • From inside the actual tank, of course. Otherwise, the test would be useless. The measurements are done over one minute.

      I don’t have information on how other countries did it, sadly.

        • The latter does not exactly sound like a terribly realistic combat scenario and, thus, presumably wasn’t bothered with. Should be safe to assume that high-tempo firing would tire the loader rather quickly though – not to mention probably causing fume build-ups inside the vehicle to further complicate things.

          • Don’t answer if you don’t know the answer.

            So EE, once again, was it “tested” during one, single minute or until all ammo was used up?

            • It would also imply the *intial* RoF before the loader started getting tired and had to begin fetching the munitions from the more out-of-the-way secondary racks would have been a fair bit higher, which hardly seems credible.

            • I don’t know how it was “tested”, but it was tested with one minute of fire.

              There is no combat scenario where you would expend your entire ammunition supply without changing targets, so there would be no point in testing it like that.

      • I understand why you would say it makes sense to do it in the actual tank but I’m not positive they actually did so unless proof of such a methodology exists. I’m not doubting you, but I don’t think it is something we should take as given. Military forces around the world are quite bad at doing independent testing without fudging the numbers in some way. Whether it is on purposeful or accidental. Would be interested to see some documentation on how such testing is done.

  8. >Q: How far did nuclear tank projects go? Are there legitimate sources on these projects?
    There were nuclear shells developed for the ISU-152, but I guess the question is about propulsion?

  9. The american T1 / M6 Heavy tank had a 37mm gun coaxial to the 76mm gun. If you google “M6 technical manual” you should find said item, which lists lots of interesting things. Like it carried canister rounds for the 37mm in addition to AP and HE.

  10. ROF is under ideal conditions, generally while the tank was completely stationary. Reloading a WW2/Korean/Arab-Israel War era tank while its on the move was hazardous. The game does not take that into account, as the in-game loader will happily load a 122mm shell while the tank is bouncing around at 50kph and sliding down a hill.

    • This is true for all tanks and quite obvious, so I dont really see your point (Mixing gameplay with real life).

      • I’d be somewhat surprised if that wasn’t the case for modern tanks, too. IIRC virtual indifference to such distractions tends to get explicitly cited as a pro for an autoloader.

  11. How they get numbers like RPM is from the timing of 1 firing cycle and then extrapolate. LOL

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