Panzer IV armour layout.

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Peasant
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Panzer IV armour layout.

Post by Peasant » 14 Jun 2020 21:34

I've created this thread to address the issue I've briefly touched on a while ago. Every source I could find reports that the thickness of this part on late Pz.IV models was left unchanged(20mm) until the end of production. But I believe that this would not be enough to afford protection equivalent to other, 80mm thick parts, of frontal armour, and so I'm asking if you have any insight on if it was actually so and why did they leave this part underprotected?

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Mobius
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Re: Panzer IV armour layout.

Post by Mobius » 14 Jun 2020 21:39

Why worry about that when they have a 50mm turret front that is very vulnerable?

Peasant
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Re: Panzer IV armour layout.

Post by Peasant » 14 Jun 2020 21:46

Mobius wrote:
14 Jun 2020 21:39
Why worry about that when they have a 50mm turret front that is very vulnerable?
Because, unlike the turret that couldn't take any more abuse, the hull still could hold more weight. After all, they did hang the spare tracks on the very front of the tank. If adding more weight there would've strained the suspension too much, they probably wouldn't do it.

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Re: Panzer IV armour layout.

Post by Yoozername » 15 Jun 2020 00:16

The angle might be even greater and the armor thicker. This is from a F model according to a British study.

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Re: Panzer IV armour layout.

Post by Yoozername » 15 Jun 2020 00:17

There are many pictures of KO'd Panzer IV with the hatches and the center access plate blown out. But I have never seen a penetration of the plate at this extreme angle.
Last edited by Yoozername on 15 Jun 2020 18:38, edited 1 time in total.

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Mobius
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Re: Panzer IV armour layout.

Post by Mobius » 15 Jun 2020 01:49

World of Tanks have data pages for the IV F2, G, H of 20mm @ 73° . I think I compromised in my data tables and have the angled bit on the G at 9cm sloped.

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Re: Panzer IV armour layout.

Post by critical mass » 15 Jun 2020 08:43

72° (I think, according to Pz IVH scheme dated 1/1945) is in the dynamic ricochet realm for impacts smaller than 0.25d/cal. Here a thinner, more flexing plate may offer somewhat more protection against holing events. The dependence on projectile geometry is very important in this obliquity realm. A pointed penetrator (or a penetrator with long pointed and solidly attached steel windscreen) very likely will ricochet after leaving a wide deflection, while a blunt headed (or blunt capped) or broken up penetrator may affect very early perforation after a long, deep gauge. The layout of the plate does not allow sufficient space to affect classical base first penetration at high obliquity without also hitting the drivers plate. Only if the projectile turns directly into the plate (possible but not very likely due to the strong trampoline effect of thin d/cal ratios) or else, if the projectile breaks up is perforation the more feasable and less resistent projectile trajectory (even at very low velocities). However, since the plate has lots of discontinuities, it will remain a weakspot, nevertheless.

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Re: Panzer IV armour layout.

Post by Yoozername » 15 Jun 2020 18:45

The Germans supposedly did tests on the benefits of having tracks or other plates as added protection. The results were that on sloped surfaces, it did have a beneficial effect, while vertical attacks did not add much. The Germans did have attachments on that area for tracks. Photographic evidence shows many Panzer IV adding more tracks and even T34 tracks. Obviously, the tanks had to have access to those hatches and the bolted on central plate.

The StuG also had a highly sloped area above the driver and opposite side to the gun.

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Re: Panzer IV armour layout.

Post by Yoozername » 15 Jun 2020 18:55

The Tiger I had 60mm at 10 degrees in a similar plate. Really, this weight and armor could have been better used elsewhere .

http://id3486.securedata.net/fprado/arm ... tiger1.htm

Peasant
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Re: Panzer IV armour layout.

Post by Peasant » 15 Jun 2020 23:34

Yoozername wrote:
15 Jun 2020 18:45

The StuG also had a highly sloped area above the driver and opposite side to the gun.
Yes, thank you for reminding me, I believe it was set at about 69° obliquity. 30mm/69° = 83,7mm LoS, the equivalent thickness of a plate set at 72° would've been 25,9mm, which supports the idea that late Pz.IVs had 25mm glacis.
I wish there was someone who could take a look with a thickness measurement device at one of the preserved Pz.IV tanks, like they did with the JS-2 to settle once and for all the question of its mantlet thickness.

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Re: Panzer IV armour layout.

Post by Contender » 16 Jun 2020 08:46

Peasant wrote:
15 Jun 2020 23:34
I wish there was someone who could take a look with a thickness measurement device at one of the preserved Pz.IV tanks, like they did with the JS-2 to settle once and for all the question of its mantlet thickness.
I actually asked him if he was willing to measure late variations of the Panzer IV H & J but unfortunately other than a favorable initial response he never got back to me & disappeared shortly after his JS-122 posts it could be due to that forum's rules. In order to post there one needs to periodically play their terrible, detestable, ill conceived, punishment "game" -a fate worse than death for many.
I had however corresponded with him in the past ~2006-ish so I may still have his old email saved in my contacts somewhere....
Anyway the armor measurement would have to be as I said above of late variations, more than one vehicle & record of what happened to the vehicles measured would be nice to avoid post-war "fixes™" or "interpretations" to fully settle the matter in my opinion.

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Re: Panzer IV armour layout.

Post by Peasant » 11 Jul 2020 14:37

Source. The data on armour thickness is probably a re-print of the information from "Preliminary Report on Pz.IV (Special)".

Interesting to note that although this tank has 50mm of armour on its vertical parts, the glacis is not 20mm but 25mm thick. Perhaps, after the order came in effect to uparmor half of production Pz.IV G with 30mm add-on armour, they were all produced with glacis thickness meant to provide homologous protection with the 50+30mm fronts.

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Re: Panzer IV armour layout.

Post by Christian Ankerstjerne » 11 Jul 2020 17:25

Please bear in mind that Allied armor thickness measurements were sometimes not accurate, so such a document is not in itself proof for the armor thickness being 25 mm rather than 20.

Peasant
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Re: Panzer IV armour layout.

Post by Peasant » 11 Jul 2020 20:46

Christian Ankerstjerne wrote:
11 Jul 2020 17:25
Please bear in mind that Allied armor thickness measurements were sometimes not accurate, so such a document is not in itself proof for the armor thickness being 25 mm rather than 20.
Yes, I am aware, but since every other measurement here is correct, as far as I know, I'm inclined to give it high level of confidence. At least for this specific vehicle.

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Christian Ankerstjerne
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Re: Panzer IV armour layout.

Post by Christian Ankerstjerne » 11 Jul 2020 22:12

It would also seem that the rear plate has an extra five mm. The incorrect angles appear fairly consistent, so perhaps the suspension was compromised?

Comparing to Panzer Tracts 4:

Code: Select all

Cupola top                         9/90      8/90
Cupola front and sides         50-95/rd  30-95/rd
Turret top front                  10/84     10/84
Turret top rear                   10/90     10/90
Turret sides                      30/26     30/25
Turret rear                       30/16     30/14
Turret front                      50/11     50/10
Gun mantlet                       50/rd     50/rd
Front vertical plate (superstr.)  50/10     50/ 9
Front glacis plate                25/73     20/72
Front upper nose plate            50/12     50/14
Front lower nose plate            30/64     30/61
Side (superstr.)                  30/ 0  20-30/ 0
Side (hull)                       30/ 0     30/ 0
Top front plate (superstr.)       12/85     11/85
Top rear plate (superstr.)        15/90     10/88
Top rear engine cover plate       10/87     10/88
Observation cover plates       20-25         ?
Belly plate                       10/90     10/90
Tail plate (upper)                20/12     20/10
Tail plate (lower)                20/ 9     20/10

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