T44 armor trials 1944

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Avalancheon
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Re: T44 armor trials 1944

Post by Avalancheon » 07 May 2019 23:01

critical mass wrote:
07 May 2019 19:56
Is2 armor triels vs kwk43/pak43:

https://warspot.ru/12831-malaya-moderni ... hogo-tanka
Looks like the Soviets tested two different types of IS-2. One with an RHA glacis, and one with a cast glacis. The cast glacis seems to offer better protection.

The 88mm kwk 43 could pierce the RHA glacis from 450 meters, and the lower hull from nearly 4000 meters (!).

The 88mm kwk 43 could pierce the cast glacis from 255 meters. Its effective range against the lower hull was presumably reduced, as well.

The article doesn't say which of the IS-2 variants entered production, though.

critical mass
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Re: T44 armor trials 1944

Post by critical mass » 08 May 2019 09:35

A couple of points to take into account:

the nose plate was 30deg, the glacis was 60deg.

Hits on the 90mm RHA glacis will break up, hits on the nose plate will not.

penetration of glacis was obtained despite projectile break up. Break up will increase variance. Therefore, I am not fully convinced that a sjperiority of the cast nose plate can be inferred from glacis data, due to the different failure modes.

Cast hull was 100mm thick, RHA was 90mm (the latter was similar to 1945 period T44A).

Avalancheon
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Re: T44 armor trials 1944

Post by Avalancheon » 08 May 2019 13:28

critical mass wrote:
08 May 2019 09:35
A couple of points to take into account:

the nose plate was 30deg, the glacis was 60deg.

Hits on the 90mm RHA glacis will break up, hits on the nose plate will not.
Penetrations from nearly 4000 meters is horrendously bad. The Soviets were wise to attach spare tracks to the lower hull, in an attempt to decap incoming projectiles and reduce their penetration.
critical mass wrote:
08 May 2019 09:35
penetration of glacis was obtained despite projectile break up. Break up will increase variance. Therefore, I am not fully convinced that a sjperiority of the cast nose plate can be inferred from glacis data, due to the different failure modes.

Cast hull was 100mm thick, RHA was 90mm (the latter was similar to 1945 period T44A).
So theoretically, the IS-2 with the cast glacis could have been penetrated from 450 meters as well? It just comes down to how much breakup is experienced by the projectile?

It would make sense. Cast armor is not as resistant as RHA, so 100mm cast would offer similar protection to 90mm RHA.

Given that the IS-2 glacis is sloped at 60 degrees, breakup has to be expected. Its less undesirable than a ricochet, anyway.


BTW, do you know precisely what alloys these two IS-2 variants used? Presumably, the cast hull used 71-L grade HHA, while the RHA hull used 42S grade HHA.

critical mass
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Re: T44 armor trials 1944

Post by critical mass » 08 May 2019 18:02

Spare tracks dont work against anything but soft caps because a large void interspace is needed between decapping plate and armor plate
to allow the knocked off cap to tear free from the projectile nose.
They eventually will give some reduction of vulnerability but not by decapping effects.

Id expect considerable variance. against 100mm hha cast at 62deg of IS3 turret armor, the 88mm pzgr39 obtained longer range penetration.
I suppose there are variances in both, projectile and armor to reckon with, here. Cast armor isnt very uniform in thickness to start with.

I have not enough information on 70l&42s to formulate an informed opinion, but I suppose that the 90mm 42s glacis was medium hardness, not HHA.
That beeing said, it should succeed in this T/D realm and obliquity to regularely manage break up of 88mm pzgr39. The 42s was not ductile enough longitudinally for this obliquity. ideally, it wouldn't break up the bullet but give in and deflect the intact projectile. Remember, the Tiger2 100mm lfp at 50deg couldnt be defeated by pzgr39 at any range.

Its important to keep these results in mind but dont jump to conclusions. the sample size is still insufficient for variance information.

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Re: T44 armor trials 1944

Post by Peasant » 10 May 2019 02:16

Avalancheon wrote:
07 May 2019 23:01
The article doesn't say which of the IS-2 variants entered production, though.
They both did. From July '44 the goal was set to assemble 250 JS-2 tanks a month, 200 hulls at factory No.200 and 50 more at UZTM. The ones made at latter were welded from medium hardness RHA. Full production numbers are shown in the table below. Note that the 250 accepted tanks goal was not reached until August.

Image

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Alejandro_
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Re: T44 armor trials 1944

Post by Alejandro_ » 17 May 2019 21:07

Mid 1944 prototype T44 armor trials vs 75mm Pzgr 39/42 & 88mm Pzgr39/43
It is nice to see you stop insisting on the T-44 being a postwar design and tested only with Soviet guns.

At this time NII48 relied on calculations. These calculations require a plate-projectile fudge factor (De Marre) and usually do not hold vs real world results. The T44 hull was tested vs domestic guns in the soviet prooving ground:
[urlhttp://tankarchives.blogspot.de/2014/02/t-44-gunnery-trials.html[/url]


viewtopic.php?f=79&t=233107&start=15

critical mass
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Re: T44 armor trials 1944

Post by critical mass » 18 May 2019 18:20

Alejandro_ wrote:
17 May 2019 21:07
Mid 1944 prototype T44 armor trials vs 75mm Pzgr 39/42 & 88mm Pzgr39/43
It is nice to see you stop insisting on the T-44 being a postwar design and tested only with Soviet guns.

At this time NII48 relied on calculations. These calculations require a plate-projectile fudge factor (De Marre) and usually do not hold vs real world results. The T44 hull was tested vs domestic guns in the soviet prooving ground:
[urlhttp://tankarchives.blogspot.de/2014/02/t-44-gunnery-trials.html[/url]


viewtopic.php?f=79&t=233107&start=15
You should read more carefully. This T44 was first tested by domestic guns. 76&85mm guns are mentioned, the former only succeeded in perforating the sides at low obliquity at 100m. Thus, the design was deemed satisfactory when tested vs domestic guns. However, as always, You misquote me, by omitting context. In that discussion, You had a habit of mixing up RHA with cast high hardness armor.. The T44 had a different type of both compared to the later T54A.

These sources deal with the subsequent T44 tests using German ordnance items, and it fared badly enough to sent the designers of what was previously deemed „satisfactory“ back to the drawing board! Only the next incarnation of the T44A had the required 90mm glacis, a dec1944 prototype and 1945 production model.
These trials are important because they demonstrated by how much domestic armor needed to be improved to deal with pzgr39. Its an important first step to move away from the standart high hardness RHA which was utilized in all T34& it’s SPG derivates towards medium hardness RHA, but it still needed improvements:
Increase in section thickness
improved temper
Addition of molybdenum
Reduction of hardness in relation to section Thickness

eventually, even the cast turret armor needed to be made of reduced hardness to guarantee optimum resistance under oblique impact.By the early 1950s, when the soviets also adopted their pzgr39 derivates for domestic AP, the cast and RHA had arrived at similar levels of hardness as german ww2 tank armor ten years ago.

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Alejandro_
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Re: T44 armor trials 1944

Post by Alejandro_ » 18 May 2019 22:07

You should read more carefully.


Yes, you are right :D . I get confused and do not understand that the "T44" was "a post ww2 tank which happened to be conceived and partially tested during ww2".

viewtopic.php?f=79&t=233107

Is it still a post ww2 tank that was partially tested during WW2?

Anyway, if the Soviets did use German ammunition. What were you referring to when you stated that "These calculations require a plate-projectile fudge factor (De Marre) and usually do not hold vs real world results"?

critical mass
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Re: T44 armor trials 1944

Post by critical mass » 04 Jun 2019 09:34

Still trolling around alejandro?

may I ask where are your ww2 T44A combat reports? no reports? But You perhaps happen to know, ww2 was a hot conflict, quiete unlike the cold war... The Pershing was a ww2 tank, even the super pershing, but the t44? nah.

As mentioned in the other thread, You miss a whole plethora of issues starting from mistaken conception of what s-42, s42s and s-42sm was to how medium and high hardness relates to the conceptualization of period vehicle protection.

You were the one who claimed that t54 glacis and side armor were uniform hardness because they both were the same material....utter fail! Denonstrating that You fail to grasp even the most basic principles of post ww2 soviet hardness conceptualization. Your understanding of german ww2 armor steel concepts isnt sth to write home, either, otherwise its difficult to explain that You fail to recognize the similarities of post ww2 soviet and preww2 german metallurgic conceptualizations. Apart from outright trolling, which probably applies here...
I think the unreflectedness of peter samsonov really is more suited to fit Your skill level in armor metallurgy, maybe You should consider staying at his site?

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Alejandro_
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Re: T44 armor trials 1944

Post by Alejandro_ » 04 Jun 2019 20:37

You get so nervous when I point out the mistakes you made in the other discussion. Now you even tell me where to participate.

Perhaps you should stop making up stuff about me and answer the original question:

if the Soviets did use German ammunition. What were you referring to when you stated that "These calculations require a plate-projectile fudge factor (De Marre) and usually do not hold vs real world results"?

critical mass
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Re: T44 armor trials 1944

Post by critical mass » 25 Aug 2019 15:45

first t44 prototype trials

Requirement: Proof vs german 75mm PAK40 (factory guarantee)

actual state tests conducted:
using 76mm F-34 firing domestic APBC-HE(blind filled) and 85mm 52-K (AAA) firing domestic APBC-HE (blind filled). The PAK-40 was not used in these initial trials, which had the aim to determine resistence vs PAK40:
"Pak 40 в ходе огневых испытаний корпуса Т-44 не использовали. Вместо этого по нему произвели 38 выстрелов с дистанции 50 м из отечественных систем. Огонь вёлся в основном 76-мм пушкой Ф-34, но лобовой лист также дополнительно обстреляли из 85-мм пушки с баллистикой зенитки 52-К. Для чистоты эксперимента каждое попадание фиксировалось."
The prototype failed to pass the trials. Later tests with the improved 2nd prototype were ordered independently (2nd prototype mentioned above already) and sidelined to the project. At that point, the decision was made upon the results of the 1st prototype (tested only against domestic AP) to massively reinforce the armor for the 3rd prototpye (later renamed T44A). This actual service version of the tank wa finally tested against german guns, with german ammunition not before Sept. 1945, i.e. after end of hostilities of the 2nd world war.

https://warspot.ru/14932-shag-v-nuzhnom-napravlenii

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Re: T44 armor trials 1944

Post by Stiltzkin » 25 Aug 2019 16:30

first t44 prototype trials
Well, I guess that settles the case.

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Alejandro_
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Re: T44 armor trials 1944

Post by Alejandro_ » 27 Aug 2019 09:03

The prototype failed to pass the trials. Later tests with the improved 2nd prototype were ordered independently (2nd prototype mentioned above already) and sidelined to the project. At that point, the decision was made upon the results of the 1st prototype (tested only against domestic AP) to massively reinforce the armor for the 3rd prototpye (later renamed T44A). This actual service version of the tank wa finally tested against german guns, with german ammunition not before Sept. 1945, i.e. after end of hostilities of the 2nd world war.
You keep changing the goalposts with every answer. Whole discussion started in another thread when you stated that the Soviets did not use German ammo during the T-44 development, only calculations:

These calculations require a plate-projectile fudge factor (De Marre) and usually do not hold vs real world results.

Then you found one of the tests carried out with one of the prototypes in September 1944, as you stated:

Mid 1944 prototype T44 armor trials vs 75mm Pzgr 39/42 & 88mm Pzgr39/43

When I pointed this out you got very agitated.

Now you go on about the different prototypes and a test conducted in September 1945. This test was not conducted on a prototype but on a production hull and turret. Also, it was not a test "against German guns", as a 85mm was also used.

critical mass
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Re: T44 armor trials 1944

Post by critical mass » 27 Aug 2019 17:07

I get agitated because You keep shifting Your idiot remarks from one aspect to another instead of confronting with the mistakes You keep presenting here.

You don´t remember? Let me quote You:
I am still puzzled by this. Let's take T-44, a WW2 design.

- Germans deploy Panzer IV with long 75mm guns, together with Panthers and Tigers, equipped with 75/88mm guns. Soviets upgrade T-34 and also decide to develop a new tank, as T-34 potential is exhausted. T-43 is dropped because is a dead end.

- T-44 is developed. Prototype is presented and tested. German PaK 40 gun, and 75/88mm guns. First can penetrate at less than 300 meters, while the latter at 700 meters. Sides are vulnerable from 600-900 meters.

Consequence: Armour is further reinforced, reaching 90mm at the front hull, 120mm in the front turret, 90mm at the turret sides, and 75mm at the hull sides.
You have it all wrong. It could have been from Mr. Samsonov, so poor is Your command of the historical causation. Why? Because You make up the claim that the 1st prototype was required to be proof AND TESTED vs PAK40. Neither it or any other prototype was ever tested against PAK40 firing Pzgr39. So hold on, Alejandro, and stop before posting or get Your facts right.
#mistake [A] -There were NO TESTS WITH THE PAK40 ON ANY T44 PROTOTYPE!
What does that mean? It was designed to be proof vs PAK40 BUT NEVER TESTED AGAINST IT. The 1st prototype was only tested vs soviet domestic 76 & 85mm guns firing soviet inferior (shatter prone) AP bullets
#mistake[ B] The decision to upgrade the frontal hull armor was not done in response to the 2nd trials but already decided in response to the results of the 1st trials. With other words, the german guns played no role in the decision to increase the glacis armor from 75mm to 90mm...

Yes there were tests with 75mm KWK42 and 88mm KWK43 with the 2nd prototype (again, no PAK40!!!) but they have absolutely nothing to do with the design decisions because the design team was sent back to the drawing boards after the results of the 1st trial poured in, and those tests were carried out with domestic guns and ammo, only. The 2nd test was virtually superflous to the design decisions, Pasholok wonders why it was staged in the first place, particularely because not PAK40 was used but the far more powerful KwK42 and KwK43.
#mistake [C] Your data on vulnerability of the 2nd prototype are wrongly staged or incorrectly explained.
Instead, let me quote pasholok:
Как показали результаты обстрела, орудие «Пантеры» пробивало верхний лобовой лист на дистанции около 700 м, а 8.8. cm Pak 43 — на дистанции 1730 м. Фактически же дистанция пробития верхней лобовой детали бронебойным снарядом орудия Pak 43 L/71 оценивалась ещё больше — до 2 км.
...
Ещё более разочаровывающими оказались результаты обстрела бортов корпуса, а также бортов башни. Под прямым углом борт корпуса пробивался пушкой «Пантеры» на дистанции около двух километров, а при курсовом угле 30 градусов — на дистанции около 600 м.
glacis: 700m, hull sides: 2000m, turret sides: 2580m, when tested with KwK42.


So what does this mean? Factory guaranteed protection of the T44 prototype (and then T44A) was calculated using a wrong De Marre fudge factor, which had little to do with the reality, as I pointed out repeatedly and You failed to accept (either by lack of comprehension or due to your fact ignoring agenda, Your choice).
In practice, this meant that the soviet design teams had no reliable data on which to assess whether or not the AFV had armor sufficient to stop PAK40 firing german ammunition. It didn´t needed them because they used calculated performance using widely distributed firing tables with wrong De Marre K (for german AP ammunition). Thats nothing scandalous in my opinion, virtually all services did the same and based enemy ordnance quality first and foremost on the presumption of similar quality to domestic stuff. The problem here is caused by the fact that the soviet domestic AP quality was so inferior to german AP-quality, that a major change in how the domestic plate fails went entirely unnoticed. Otherwise, they could have improved (soft tempering) 42S- steel already during wartime but this did not happen (on systematic base) before 1950. As it was, the material was too hard and would give in easily at acute obliquities to german Pzgr39, a feature which is esspecially undesired because the soviets were fond of high obliquities...
They tested the 1st prototype exclusively with soviet domestic guns and AP ammunition, and this prototype failed. Following this, they decided to upgrade the armor before the 2nd set of trials were staged. The 2nd set was ordered anayway and even while the design changed already, nobody tooks steps to stop the trials. They are highly interesting to the researcher because it is a rare cross country test case but it has nothing to do with the decision making process in the T44 project. The original T44 was dead by then and the T44A wasnt tested against german guns until after ww2. So again, Alejandro, GET YOUR FACTS RIGHT AND STOP POSTING BS.

And yes, the T44A is by all accounts a post war AFV. That its design history involves steps and decisions made during ww2 does not mean it was a ww2 fighting AFV. 2out of 6 production T44A couldnt successfully pass a 300km run in may, 1945. None of ten survived a 1000km run. During 1945, it was still technically immature (in this regard its save to conclude that its mechanical reliability in 1945 was grossly inferior even to the PANTHERs in 1943).

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Alejandro_
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Re: T44 armor trials 1944

Post by Alejandro_ » 27 Aug 2019 22:02

I get agitated because You keep shifting Your idiot remarks from one aspect to another instead of confronting with the mistakes You keep presenting here.
Now you are getting hysterical. This is what you originally stated:
However, the T44, which in itselfe was a post ww2 tank which happened to be conceived and partially tested during ww2, was specified to resist domestic AP, and at one point had the requirements to include also german AP resistence.
Now you go on about prototypes being unrelated, and pretend a September 1945 test on a production hull/turret is in fact with a prototype.

Perhaps you could start by reading again Pasholok article, where it states that T-44A is an improved version of T-44, and not that the T-44 was a dead end. But don't worry, don't let reality get in the way of fantasy.

At least you admit that Soviets did use German ammunition in the design.
It was designed to be proof vs PAK40
We seemed to be moving forward here. Not long ago you stated that the T-44 "was specified to resist domestic AP"
The decision to upgrade the frontal hull armor was not done in response to the 2nd trials but already decided in response to the results of the 1st trials. With other words, the german guns played no role in the decision to increase the glacis armor from 75mm to 90mm...


Actually, this is not the case. GBTU KA decided that protection requirements (75mm PaK 40) did not adjust to realities of the front and decide to upgrade protection to take into account Panther and Nashorn guns, which are then used in testing.

Let's see one of the outcomes of the test:

The test result was logical. The T-44 of the second variant turned out to be completely defenseless against the fire of the 88-mm Pak 43 gun, and only the frontal part of the hull was protected from the fire of the Panther gun, and even that at distances of 800-1000 m and further. Thus, the expediency of increasing the thickness of the armor, which was repeatedly demanded by the management of GBTU KA, was once again confirmed.

After shooting tests, there was another requirement - to increase the thickness of the sides to 90 mm in order to protect the tank from the fire of the Panther’s gun at least at medium distances.


Just like in your fantasies, T-44 requirements were vs Soviet ammo and it was never tested against German ammunition.

https://warspot.ru/15111-vsyo-eschyo-s-budkoy
The original T44 was dead by then and the T44A wasnt tested against german guns until after ww2. So again, Alejandro, GET YOUR FACTS RIGHT AND STOP POSTING BS.


Again, you keep trying to hide your mistakes by changing your version again and again. Initially you refer to a "T44" being "conceived and partially tested during ww2". Now the "T44" was a dead end, and the "T44A" was "tested against German ammo in September 1945".
2out of 6 production T44A couldnt successfully pass a 300km run in may, 1945. None of ten survived a 1000km run. During 1945, it was still technically immature (in this regard its save to conclude that its mechanical reliability in 1945 was grossly inferior even to the PANTHERs in 1943).
How can you "safely conclude" Panther D was more reliable?

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