8,8 cm PzGr 39 Performance

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Mobius
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Re: 8,8 cm PzGr 39 Performance

Post by Mobius » 22 May 2021 14:08

critical mass wrote:
22 May 2021 13:25
30 deg series
70mm: 905m/s (sic. unknown if typo)
60mm: 721m/s
50mm: 624-658m/s
40mm: 508m/s
30mm: 407m/s

45 deg series
60mm: MV
50mm: 805m/s
40mm: 670m/s
35mm: 610m/s
30mm: 507m/s
CM, do you have a firing table for this round? I have nothing on the ballistics.
It's not very different from the graph of the pzgr 39 in Lilienthalgesellschaft-1943
30 deg
70mm: 813m/s
60mm: 708m/s
50mm: 626m/s
40mm: 521m/s

ThatZenoGuy
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Re: 8,8 cm PzGr 39 Performance

Post by ThatZenoGuy » 22 May 2021 15:39

critical mass wrote:
22 May 2021 13:25
ThatZenoGuy wrote:
22 May 2021 11:45

That picture interests me, what the heck is a PzGr 42 50mm projectile?

Also I think I've seen a picture referencing a PzGr 44 88mm (?) projectile from one of your posts, what is that? ;v
Which post? This is not a Pzgr.44. Its a 5cm Pzgr.42. These were developed to improve upon the 5cm Pzgr.39 downrange performance and obliquity performance. First delivery was made in august 1943 with proof trials conducting in septemper yielding these G(D) results:

30 deg series
70mm: 905m/s (sic. unknown if typo)
60mm: 721m/s
50mm: 624-658m/s
40mm: 508m/s
30mm: 407m/s

45 deg series
60mm: MV
50mm: 805m/s
40mm: 670m/s
35mm: 610m/s
30mm: 507m/s

Little improvment had been obtained at 45 deg as compared to the 5cm Pzgr.39...
Image
This one! ;D

Edit: Also did Pzgr 42 50mm ever get used in combat properly?

Peasant
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Re: 8,8 cm PzGr 39 Performance

Post by Peasant » 22 May 2021 15:47

critical mass wrote:
20 May 2021 14:39
Too many assumptions.

(A) there were VERY FEW normal obliquity tests against the T44. Altough shot by shot data are missing, only four out of fourteen tests were within the proof angle of either 75mm or 88mm Pzgr.39. Thus, the majority of the penetrations should behave exactly as observed. Further, only ONE shell can be charackterized as undamaged in the photo. All shell hits on the front were > proof angle for the Pzgr.39 and the majority of side hits were also at resolved netto compund obliquity >45 deg. The only tests against the side at 30° or 0° yielded such low PSP velocities (487m/s and 595-596m/s) that no damage would have occurred at all to any 88mm or 75mm shell. Without knowing which projectile corresponds to which test, assumptions are uninformed, and thus, not a good advisor. Because they fired life shells, all functioning shells would be highly fragmentated. You wouldn´t have them selected for the photo. This can bias Your perception considerably.
-Also, impacts at high obliquity do render the projectile defunct primarely by forms of base slap, which damages the fuze adaptor. Nose breakage against high obliquity targets is a good feature as it inhibits ricochet.

(B) the 2nd image shows an early KW armor trial, at which time the 5cm Pzgr Gg were in service, primarely. These early ww2 uncapped 5cm shells started to experience break up at ca. 600m/s terminal velocity against a target plate, which they could barely perforate. Those shells would break up against a discriminate target, such as those 75mm plates depicted. Again, You are assuming the projectile was intact, but the fact that the nose is not shown tells me that this is not a likely assumption. In low obliquity impacts the function of a shell is compromised primarely by nose breakage or compression reaching down to the cavity. These shells could not be relied upon to survive this impact in a condition fit to burst.
Yes, you are making a good point, the projectiles wouldn't be recovered if they perforated the armour in condition fit to burst. It's the so called "Survivorship bias". And I guess not even the germans would waste resources on putting fuzes in their AP shells if the HE charge inside was not enough to fragment them.

About your second point, idk I feel like even a low order detonation would rip the shell out of the armour, not left it stuck like this, but it's not like I have anything to go by other than my intuition.

critical mass
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Re: 8,8 cm PzGr 39 Performance

Post by critical mass » 24 May 2021 09:19

ThatZenoGuy wrote:
22 May 2021 15:39
critical mass wrote:
22 May 2021 13:25
ThatZenoGuy wrote:
22 May 2021 11:45

That picture interests me, what the heck is a PzGr 42 50mm projectile?

Also I think I've seen a picture referencing a PzGr 44 88mm (?) projectile from one of your posts, what is that? ;v
Which post? This is not a Pzgr.44. Its a 5cm Pzgr.42. These were developed to improve upon the 5cm Pzgr.39 downrange performance and obliquity performance. First delivery was made in august 1943 with proof trials conducting in septemper yielding these G(D) results:

30 deg series
70mm: 905m/s (sic. unknown if typo)
60mm: 721m/s
50mm: 624-658m/s
40mm: 508m/s
30mm: 407m/s

45 deg series
60mm: MV
50mm: 805m/s
40mm: 670m/s
35mm: 610m/s
30mm: 507m/s

Little improvment had been obtained at 45 deg as compared to the 5cm Pzgr.39...
Image
This one! ;D

Edit: Also did Pzgr 42 50mm ever get used in combat properly?
There is no 50mm Pzgr. 42 in this graph. The drawing shows a 88mm Pzgr. 44 (not standartized). Notice the difference in the headshape. The Pzgr.44 was supposed to have a 0.50 crh hemisspherical noseshape rather than the somewhat pointed Pzgr.39 and -42.

From what I read in the sources, the Pzgr.42 was provided when the 50mm KWK39 was relegated to secondary use. It saw eventually service as AP-ammunition for the feww 50mm FLAK41 guns. It may also have seen service in Spähpanzer, but I am not certain in regard to the latter. I cannot comment on whether or not it saw service in PAK39 but I doubt it.
CM, do you have a firing table for this round? I have nothing on the ballistics.
It's not very different from the graph of the pzgr 39 in Lilienthalgesellschaft-1943
30 deg
70mm: 813m/s
60mm: 708m/s
50mm: 626m/s
40mm: 521m/s
No. the penetration data are retrieved from ADM 213/951. Because both projectiles varied very little in headshape, the differences in cap weight and shape are not large enough to cause substantial differences in 30° obliquity penetration performance, where both Pzgr. 39 and Pzgr.42 can be relied upon to stay intact. The difference are in 45deg obliquity, where the Pzgr.42 can be relied upon to perforate intact, while the then in service 5cm Pzgr.39 could only sometimes stay intact. Because the 5cm calibre was deemed obsolete by late 1943, the imrpovements in heat treatment achieved by the Pzgr.42 program were then simplified and re-applied to the 75mm, 76.2mm and 88mm projectiles in 1944, so that by autumn 1944, new proof specifications were issued calling for 45deg proof.

Peasant
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Re: 8,8 cm PzGr 39 Performance

Post by Peasant » 24 May 2021 10:33

critical mass wrote:
24 May 2021 09:19
Lately I've been pondering on whether or not it would've made for a more effective weapon if the germans forgone entirely the high explosive filler in their AP shells and went with un-capped solid shot with just a windshield on, sorta like the US T33 series. The newest generation of tanks were relying more and more on sloping of the armour rather than on thick plates set at low obliquity and even in vehicles that had both present, the former was covering much more area than the latter.

critical mass
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Re: 8,8 cm PzGr 39 Performance

Post by critical mass » 24 May 2021 12:16

This indeed might have been better vs 1945 soviet tank designs but it would have been worse vs contemporary western tank designs, such as the CENTURION or PERSHING, which relied upon considerably softer armor grade, where the uncapped APBC will run into problems defeating the armor from low energy shear plugging but instead would have needed to defeat it by plastic deformation (the APBC sans AP-cap will break up, requiring a larger diameter hole to be made). It seems to me that the 88mm was more or less the end of the German high velocity buisness, as most large cal high velocity anti tank gun projects were dropped and ammunition technology foccussed more and more on HEAT-FS, with either slipping driving bands or in combination with lightweight PAW smoothbores. These combinations, I think, were better suited to deal with highly oblique armor plate than APBC.

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Re: 8,8 cm PzGr 39 Performance

Post by ThatZenoGuy » 24 May 2021 16:27

critical mass wrote:
24 May 2021 09:19


There is no 50mm Pzgr. 42 in this graph. The drawing shows a 88mm Pzgr. 44 (not standartized). Notice the difference in the headshape. The Pzgr.44 was supposed to have a 0.50 crh hemisspherical noseshape rather than the somewhat pointed Pzgr.39 and -42.

From what I read in the sources, the Pzgr.42 was provided when the 50mm KWK39 was relegated to secondary use. It saw eventually service as AP-ammunition for the feww 50mm FLAK41 guns. It may also have seen service in Spähpanzer, but I am not certain in regard to the latter. I cannot comment on whether or not it saw service in PAK39 but I doubt it.
I know the 42 is not in the picture, I were merely asking you about the 44. Like, what is the 44 supposed to be? Was it ever used? A picture of it? Etc?

critical mass
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Re: 8,8 cm PzGr 39 Performance

Post by critical mass » 25 May 2021 13:19

The Pzgr.44 was supposed to replace the Pzgr.39 and traded vertical penetration for improved oblique penetration. Because it was never standartized it follows that it was also never used in combat.

ThatZenoGuy
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Re: 8,8 cm PzGr 39 Performance

Post by ThatZenoGuy » 25 May 2021 14:18

critical mass wrote:
25 May 2021 13:19
The Pzgr.44 was supposed to replace the Pzgr.39 and traded vertical penetration for improved oblique penetration. Because it was never standartized it follows that it was also never used in combat.
Understood, thank you! So its sorta a capped 'blunt shell'?

Would make sense if more and more sloped vehicles kept showing up from Russia's factories. Wasn't something as 'primitive' as the IS3 immune to the 88 for the most part?

critical mass
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Re: 8,8 cm PzGr 39 Performance

Post by critical mass » 26 May 2021 11:35

The IS3 was designed to be resistant vs KWK43 firing A.P. and it shows the progress made. There is no need to be judgamental, and I dislike the use of the word "primitive". IS3 was still vulnerable to mines, artillery, or KWK 43 firing rare AP40 ammunition, though, let alone 12.8cm or HEAT...

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Re: 8,8 cm PzGr 39 Performance

Post by ThatZenoGuy » 26 May 2021 12:34

critical mass wrote:
26 May 2021 11:35
The IS3 was designed to be resistant vs KWK43 firing A.P. and it shows the progress made. There is no need to be judgamental, and I dislike the use of the word "primitive". IS3 was still vulnerable to mines, artillery, or KWK 43 firing rare AP40 ammunition, though, let alone 12.8cm or HEAT...
I only used the term primitive because the Soviets would later have IS4's, T-10's, and other far more heavily armored tanks rolling out. By postwar heavy tank standards the IS3 was kind of primitive. ;D

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Re: 8,8 cm PzGr 39 Performance

Post by Thoddy » 27 May 2021 10:06

With regard to hemispherical and eliptical shapes

These types of headshape provide the lowest shatter velocity, according to "Effects of impact and explosion".
"Should therfor be avoided for attack of thicker plates"
https://apps.dtic.mil/sti/citations/AD0221586
pages 191ff in the PDF

Despite posessing comparatively low energy consumption at high obliquity impacts (>45 degrees)-because projectiles tend to scoop with increasing caliber ogives.
"Meine Herren, es kann ein siebenjähriger, es kann ein dreißigjähriger Krieg werden – und wehe dem, der zuerst die Lunte in das Pulverfaß schleudert!"

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Re: 8,8 cm PzGr 39 Performance

Post by Mobius » 31 Jul 2021 16:17

Here is an interesting simulation of the 88mm.
https://www.youtube.com/watch?v=WVvA6TYXMLI

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Re: 8,8 cm PzGr 39 Performance

Post by ThatZenoGuy » 03 Aug 2021 15:58

Mobius wrote:
31 Jul 2021 16:17
Here is an interesting simulation of the 88mm.
https://www.youtube.com/watch?v=WVvA6TYXMLI
I always have some doubts about these videos, its as though the 88 struggles somewhat against the T-34, meaning the 75mm Panzer 4 would struggle yet further due to less kinetic energy and a smaller diameter to overmatch. But it seemed historically the 75 punched through them pretty easily, even at long ranges.

I can only assume due to the application of high hardness steels on the sloped parts of the tank, which is a bad combination usually?

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Re: 8,8 cm PzGr 39 Performance

Post by Mobius » 03 Aug 2021 16:08

The computer model doesn't show any shock wave motion. This causes an edge effect crack. I guess the armor is suppose to extend on to infinity from the area shown.

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