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"?

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