Thursday, 13 October 2016

Beefy T-28

Soviet T-28 and T-35 tanks catch a lot of flak for being big, heavy, and not particularly well armoured in the era where anti-tank cannons became very common. German pre-war intelligence identifies the T-28 and T-35 as vulnerable to 37 mm guns from 450 meters, and yet the 94th Anti-tank Squadron of the XXXXIX Mountain Corps had a different experience. In a report titled "experience of an anti-tank unit in the East" they write:

"In one case, we managed to impede the attack of a heavy Russian tank "T-28" (or "T-35") by disabling its turret rotation mechanism. Shooting at the front or sides of the turret with PzGr 39 and PzGr 40 shells out of 37 mm guns at a range of 250 m had no effect."

CAMD RF 500-12480-145

28 comments:

  1. Perhaps it was a uparmored t-28 e or a improvised uparmoring?

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    1. Also out of pure curiosity i wonder if there ever were instanced where t-28s had their mg turrets removed for one reason or another.

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    2. Most likely it was an uparmoured version, as the 3.7 cm Pak should be able to penetrated a regular T-28. I haven't seen any T-28s without their MG turrets.

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  2. "no effect" does not necessarely mean that the projectile also failed to penetrate.

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    1. Having the turret shot full of holes rather tends to have fairly immediate and obvious "effects" on AFVs in action though?

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    2. And more practically 37 mm antitank guns were more or less what T-28s were given appliqué armour *against* in Finland... would seem somewhat obvious enough metal was added to render decent protection against shells in that class while they were at it.

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  3. Applique armor would be very useful against a bullet of this size. Not so much at normal obliquity but particularely severe effects have to be reckoned with at moderate obliquity where projectile damage adds to the effects.

    However, "Beschuß ohne Wirkung" -which is the literal translation of "shooting (...) without effect" does not necessarely qualify to presume that the projectile failed to penetrate.

    "effect" was defined in german sources by the ability of the projectile to burst behind armour plate high order and this could be compromised, f.e. by

    a) oblique impact and projectile break up
    b) shatter at high velocity impact
    c) fuze failure

    A penetrating projectile which ended up as dud perforating both sides (in- and out) would always be classified as "ohne Wirkung" unless it happened to set off ammuntion or gas. It may penetrate -but if the projectile didn´t burst, it´s not regarded as effective.

    The german definition in this regard differs from soviet or western allied definition.

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    1. You're kind of implicitly assuming a REALLY low sample size there whereas the report speaks in plural, implying multiple guns and quite a bit of shooting (as tends to happen when you need to stop a tank which, well, doesn't). Moreover I was under the impression the PzGr 40 APCR shells were quite devoid of bursting charges to begin with...?

      Also since this is a report of live combat rather than formal testing I think it should be safe to assume "no effect" should be read as "made no holes and did not perceivably discomfit the tank" - that being what actually matters under such circumstances. If fuze failure was the problem you'd expect bitching specifically about that topic as soldiers tend to dislike weapons that don't do their jobs; assuming the tank in question fell into German hands afterwards they could simply check, by inference if they were achieving penetrations without apparent "terminal effects" of the sort you'd expect from a shell bursting inside a turret if it was able to leave the field.

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  4. They would use a different term if the problem would have been ascribed to failure of penetration. The term used then in AAR was "ohne Durchschlag".
    "ohne Wirkung" means that the object was hit but not perceivably suffered damage -for whatever reasons.

    I have studied AAR where T34 turret crew were killed due to penetrations but the driver still worked and moved the tank to overrun a gun. The company experiencing this event would always classify the firing as "ohne Wirkung" in the AAR, sometimes adding more detail. Lack of penetration does also led to "ohne Wirkung" but both aspects are not correlated, the former is generally given as "ohne Durchschlag" or "ohne Durchschlagswirkung".

    Your presumption that "no holes were made" therefore cannot be deduced from the source describing a lack of behind plate effects.

    Assuming how things "should be read" is dangerous as it could lead to wrong conclusions.

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    1. The account rather strongly implies it was specifically the jamming of the main turret that rendered the tank in question hors de combat, or at least persuaded it to break off the attack. That HARDLY suggests the "main battery" occupants were dead or incapacitated (as would almost certainly be the case if penetrations were achieved); it's quite difficult to see why the driver, if he was de facto making the decisions on account of the TC being out, would suddenly develop cold feet due to the already impotent main turret jamming - or for that matter, how that particular bit of damage would even be noticed in the first place.

      Not to mention that T-28 still has the two MG sub-turrets to fight with even if the primary is lost.

      Summa summarum: the scenario plain does not compute if you assume penetrations. Why would the report explicitly single out jamming the main turret if they could've just, y'know, shot the tank to pieces anyway?

      Plus the penetration figures I could quickly find for the 3.7 cm PzGr 40 aren't exactly awe-inspiring at something like ½ km already. No idea what kind of turret this tank specifically had (the late-production conical one with appliqué?) and what the effective thickness was, but given that unreinforced T-28s were AFAIK readily enough Swiss cheesed already by AT guns *smaller* than 37 mm (French-supplied 25 mm's worked pretty well in Winter War IIRC) it should be safe to assume enough steel had been added where it counted to fairly reliably defeat guns of that caliber at least.

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  5. [A] too many assumptions. The source can be interpreted in ambivalence but it appears people are eager to jump to conclusions...

    [B] You try to redefine the prior conditions by applying posterior information without any knowledge of the former or the mode of action. This forces u to conclude the T28 was uparmored because You presume penetrations did not occur in the first place. In fact, neither need to be true in order to agree with the description forwarded here.

    [C] terminology used here doesn´t fit with the terminology used in german sources for description of non-penetration events. It´s fair when You state that Your interpretation of the event suggest to You that the failure to exert effect might be related to a lack of penetrations but then it´s also advised to stress that it´s Your interpretation and not the sources.

    As for early ww2 3.7cm ammunition, such as the 3.7cm Pzgr. (AP-HE) or 3.7cm Pzgr.18 (AP-HE), it penetrates -in a condition fit to burst- a high hardness plate (110 to 115kg/mm^2 tensile strength) of 30mm RHA thickness at an obliquity 30° from the normal and a velocity of 560m/s (german definition: ten successes out of ten tests in a narrow velocity range).
    Early uncapped AP broke regularely up striking at obliquities >30° or at high velocity, corresponding to short range. Break up occurred more completely and at lower obliquities or lower velocities against harder plates and if it occurred, the energy consumed to break the projectile up resulted in a significant decrease in penetration (by up to 1/3 at normal), plus low order detonation or outright duds.

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    1. So riddle me this: if the guns DID penetrate, then why is the jamming of the turret singled out as how the tank in question was dealt with?

      Solid-shot penetrators already tend to do all kinds of Bad Things to people and equipement in the space behind the armour; if you can get shells through the plate in the first place you're going to be fucking shit up in there.
      Yet it is the primary turret becoming jammed that gets specific mention.
      We can infer a number of thing from this:
      - first, the turret was being "fought", for its freezing to be noticeable in the first place
      - second, ergo people and machinery were still more or less in one piece in there
      - third, ergo no substantial penetrations had been achieved
      - fourth, ergo the turret (and presumably other important areas) had been sufficiently up-armoured from the original thicknesses to reliably resist the 37 mm gun, even APCR, at the ranges in question

      Furthermore as far as I'm aware losing the use of the main turret and, thus, the main gun was pretty universally taken by tank crews as the que to GTFO the battlefield if not straight up bail out of the can - case in point, this was how the Brits captured one essentially intact in Tunisia.

      The most obvious reconstruction of the events would thus be that the PaKs bounced shells off the tank until the turret traverse was disabled one way or another, at which point the crew either beat a hasty retreat or bailed out.

      You're welcome to offer alternative scenarios, of course, but the above would to me appear both the most plausible and the least convoluted.

      On another note I'm not sure what you're trying to say with that last block of technical detail, other than that straight up failure to penetrate was only too likely? :/

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    2. er, "-- captured one Tiger --"

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    3. The turret was jammed -but the exact wording used was "by disabling it´s turret rotation mechanism", which might leave a number of possible causes, including internal damage caused by impact upon turret rotation gear, requiring a penetrative effect. With the information at hand, this question cannot be resolved.

      AsI mentioned previously, You are free to have You own opinion but You are not free to have Your own facts.

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    4. Pretty sure turret traverse mechanisms were damaged by non-penetrating hits all the damn time though? They kind of get subjected to a fair bit of the impact shocks after all...

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    5. And that's not counting the good old shell wedged in the turret ring and physically preventing rotation by its mere presence, ofc.

      As far as the shooter in combat is concerned the difference between the causes of the turret jamming are QUITE academic. Salvage crews and whatevers can make a more precise diagnosis in due time, in action what matters is that the enemy unit has suddenly pretty much lost the use of its main armament.

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    6. "You're making too many assumptions"
      *immediately makes a shit ton of assumptions*

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  6. Document: "No effect"
    Critical mass: "Actually, no effect doesn't necessarily mean there was no effect and it means there could have been an effect!"

    Go back to your fantasy world and quit polluting my comments.

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    1. Peter, You make a mistake. Effect and penetration are not the same and are not treated as equal in german sources.
      They are maybe treated the same in soviet sources, but that´s a different kettle of fish.

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    2. All your going on about German definitions of "effect" is rendered roundly irrelevant by two factors, you know.

      First, the explicit mention of PzGr 40s being also used; as APCR shells quite devoid of either bursting charges or fuzes any considerations of behind-armour detonation plain do not apply. (I'd love to hear your take on how the Germans defined "effect" for such solid shells in general...)

      Second, the Germans observing the shell impacts would simply have had *absolutely no way of knowing* what happened after a penetration was achieved, if one now was in the first place; they were apparently several hundred meters away, given the cited engagement distance, and watching through gunsights (AT gunners) and/or binoculars (any gun commanders observing the shots), not equipped with comic-book superhero X-Ray visions or some kind of ESP. There are exactly two kinds of "effect" they WOULD be able to perceive - whether a shell penetrated or not, and if a hit had any apparent effect on the target.

      Considerations of fuze action and/or failure, shell break-up etc. are concerns for the testing range and perhaps post-battle analysis if the enemy unit falls to your hands in a shape fit for closer technical investigation, not troops in combat desperately trying to stop a fucking tank advancing on their lines.

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  7. The interpretations You attempt are not justified or based upon sources. In short, You are making it up by presuming penetrations did not happen when in fact only a lack of target effect was reported. Let me quote a service regulation on 37mm AP-HE and 37mm Pgr40 (Hk) (D.V.):

    "Zwischen den Geschossen besteht insofern ein grundsätzlicher Unterschied, als dass die Panzergranaten die Aufgabe haben, eine kleine Menge Sprengstoff nach dem Durchschlagen ins Ziel zu transportieren und dort wirksam werden zu lassen, während die Hartkerngeschosse keine Sprengladung besitzen, die das Geschoss zerlegen. Ohne diese Zerlegung kann es vorkommen, *dass schwach gepanzerte Fahrzeuge glatt durchschlagen werden, ohne außer Gefecht gesetzt zu werden*. Zugunsten des Durchschlages wird bei Hartkerngeschossen daher auf eine Wirkung verzichtet." -emphasized with ** by myselfe

    Lack of perceived target effect thus, is nothing special with Pgr40 but realistically has to be reckoned with, particularely when stiking thinly armoured targets. This would today be classified as an inconsequential penetration.

    The real difference is that while the germans were in possession of projectiles with post plate effect, the Red Army did not had anything remotely comparable in terms of effect behind armor plate and for them, effect was ALWAYS tied with penetration. The soviet perspective, however, does not qualify for german sources because they DO differ in describing effect and penetration.

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    1. You've yet to present any kind of plausible scenario where penetration were achieved WITHOUT "effect", until what's described as disabling of the turret rotation "impeded the attack".

      This quite simply does not compute. Are you implicitly assuming that A) all the APHE fuzes failed and B) the Soviet tankers inside were made of fucking armoured steel to not be reduced to paste by all the fun shit that happens when things come through the armour?

      'Sides, why would the comparatively scarce and expensive APCR shells have been broken out in the first place if the humble PzGr 39 was already going through, anyway? Without bursting charges they could scarcely have MORE "effect" in the ehind-armour sense, nevermind now being gross overkill.


      I'm also frankly puzzled why you're building a mountain out of this molehill. The rapidly declining relevance of antitank guns in the 37-40 mm range already in the early war years, even the likes of the rather higher-velocity US and Brit designs, wasn't exactly a contentious topic the last I checked. I mean - the Germans themselves were trying to replace them with 50 mm's as fast as they could.

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  8. I do not need to present an alternative scenario. I already pointed out that multiple theories can be put forward to explain the event and that present information is insufficient to resolve the question. It´s sufficient to know that lack of penetration cannot be considered an exclusive cause when only a lack of effect is reported.

    My critique is not a defense of the 37mm, it´s a much more fundamental aspect, outlining that more care should be paid in interpretation of source information. Jumping to conclusions may be temptive but without proper understanding of the context of the source and the limits of the terminology employed therein, You will end up extracting conclusions which are not backed by the source and marginalize possible alternative interpretations.

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    1. You've yet to put forward even ONE such a theory. And anyone who argues that a given proposed scenario is flawed should damn well better be prepared to offer an alternative explanation if challenged to do so, thankyouverymuch.
      That alternative had bloody well better be *plausible* too.

      Which is kind of the issue here. Your objection is based ENTIRELY on mere terminological pedantry and categorically ignores the minor detail that it requires a scenario that is wholly absurd, as already outlined above. (You've yet to even try to refute even one of the problems raised.) Meanwhile the report apparently could not even positively identify which *kind* of multi-turreted tank was involved - you'd think even busy gun crews could eyeball the number of turrets at least - which should tell volumes of how concerned the people writing it were with such technical nitpickery...

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  9. Try to read my response above. Use a translator if You can´t read german, no need to repeat.

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    1. I did. (Bit of a poor form for you to neither give at least a rough translation nor specify the source, btw.)

      It appears to have little to no relevance to the topic and does nothing to explain away the numerous issues with the kind of scenario your objections imply.

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    2. Orite, you did mention the source. My bad.

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  10. It tells all about the problem. You asked which scenarios are possible, here are some:

    originial turret:
    A 37mm AP has been fired without effect. Due to obliquity, the shell glaned off without penetrating. Then 37mm APCR have been fired. Due to overpenetration, the small core perforated in-and -out of the turret without hitting something vital. No effect was observed until finally the turret mechanism was hit.

    B)
    37mm AP has been fired, due to moderately oblique impact, the fuse rendered the projectile blind. It penetrated the turret but didn´t hit something vital behind. Then 37mm APCR are fired, due to overpenetration, the core went through without apparent effect until it hit the turret turning mechanism.

    reinforced turret:
    C) 37mm AP was fired and failed to hole the turret armor. Then 37mm APCR was fired and the core penetrated the turret without hitting something physically important behind

    D) 37mm AP was fired and failed to hole the turret armor. Then 37mm APCR was fired and the core failed to penetrate the turret

    All options are possible and explainable by the account. As evidenced by the source I gave, the lack of observed effect does not necessarely mean that no penetration was happening, too. It´s just one option of many.

    As always, it´s better not to jump to conclusions.

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