Panther Glacis Quality on Eastern Front

[rexford]

The IS-2 development notes on the subject web site suggest that Panther armor decreased in quality during the Summer of 1944 (see following web page: [url=http://history.vif2.ru/is2_1.html):]

"Further, after the first encounters between the JS-2 and German heavy tanks, it turned out that the sharp-nosed 122 mm APHE round - the BR-471 - could only penetrate the frontal armour of a Panther up to 600-700 metres. The less powerful frontal armour of a Tiger could be penetrated at distances up to 1200 metres. However, at such distances only very well trained and experienced gunners could score a hit. The vertical armour of a Tiger I, although thicker than that of a Panther, was more easily defeated by the sharp-nosed projectile of the JS-2 Main Gun, whilst it often ricocheted off the sloped armour of a Panther. Later, Soviet designers noticed the blunt-nosed projectiles worked fine against sloped armour. After several tests, designers revealed the effect of "normalisation" (Read more about "normalization" effect here). The powerful HE round, OF-471, when fired at German tanks, caused cracking and could even completely tear off the front armour plate at the seam weld. The first results of the IS-2 in combat (backed by the results of its tests at the Kubinka testing grounds in January of 1944) forced designers to look for new solutions to its problems.

However, in the summer of 1944, the problem of the poor AP performance disappeared. The performance of the D-25T gun of the JS-2 against the German tanks improved dramatically. The reports from the front described cases where the BR-471 APHE round 122 mm projectile fired from 2500 metres ricocheted off the front armour of a Panther leaving huge holes and cracks in it."

The Allies also noted poor performance of Panther glacis during the summer of 1944, two of three Panther glacis at Isigny crack after a few 17 pounder APCBC hits and American analysis of glacis metal shows brittle characteristics and low impact resistance.

It would seem from the above that Panther glacis plate armor was fine until mid-1944, and then brittle or reduced effectiveness armor may have appeared on both the Eastern and European Fronts.

British analysis of Tiger and Panther armor prior to 1944 states that it was good with an occasional bad plate.

If the slope multipliers for Allied solid shot AP are applied to Panther glacis, the resistance equals about 168mm for 80mm at 55 degrees armor, which is penetrated by 122mm AP at 625m, close to Russian combat experience of 600 to 700 meters.

Since the AP analysis does not assume any loss in armor resistance, it suggests good quality ductile armor resistance during the initial IS-2 vs Panther engagements where the 122mm gun was used, which may have included cold weather battles (Panther armor would have performed well despite cold, attesting to good quality).

Blunt nose 122mm APBC would penetrate 80mm at 55 degrees beyond 1500m, which is slightly larger than what the Russians reported.

Bottom line is the Eastern Front combat model for Panther might assume good quality armor till summer of 1944, and then assign reduced quality modifiers to a percentage of the Panther glacis armor.

U.S. firing tests against the rest of the Panther armor (besides glacis), and Russian statements regarding Panther non-glacis armor, indicate good quality.

The percentage of Panthers that would be impacted by armor changes is not known.

[ 12-30-2001: Message edited by: rexford ]</p>

[rexford]

Summary of previous post:

1. Panther glacis sound till summer of '44 (quality is 1.00 prior to that time)

2. Starting summer '44, Panther glacis appears to lose something resulting in more fragile nature and increased penetration ranges

3. Not well known what percentage of Panthers have deficient glacis armor

4. IS-2 tanks shoot AP and APBC from their guns in unknown mix, earliest IS-2 fire sharp nose AP exclusively, it would seem

5. Russians unaware of superior slope effects of blunt nose APBC until it goes through good quality Panther glacis at 1200m, when they run tests to see what is happening

6. Russian uncapped AP appears to use same slope effects as American and British solid shot AP:

slope multipliers equal (^ raises term to immediate left by factor to right of sign):

65 degrees: 2.91 (T/D)^0.1864

45-60 degrees: (0.715 x 1.02^(angle))x (T/D)^(0.0779 x 1.0095^(angle))

40 degrees: previous equation x 1.05

30 degrees: 45-60 degrees equation x 0.95

7. penetration tests at Kubinka suggest that Panther glacis loses more than 15% of resistance when it is hit by 122mm APBC, due to plate problems

8. Russian experience during summer of '44 consistent with U.S. tests at Isigny during August '44 and metallurgical analysis of one Panther glacis (low impact resistance and brittle structure)

[Redwolf]

Hi, rexford,

I didn't get the statement about the OF-471 HE shell. Was that shell intended to be used against armour and if so from what vehicle/gun?

[offtaskagain]

I have a question in regards to the HE rounds cracking the plate at its welds. In "Death Traps" the subject of poor German welds is brought up. Cooper examined one of the KTs abandoned after they mauled a task force at Paderborn. It had been hit on the corner of the glacis by a white phosphorus shell. The plate had cracked the welds at that corner just from a measley little 75mm WP shell. Cooper then explains why the welds broke so easily. Apparently the normal way to fix two plates together is to have the edges that are to be welded together kind of tapered so that a triangle shaped gap is formed between the plates.

Kind of like this

______ ______

______\/______

The weld is started on the wedge until it's filled. Then the welder moves to the back side and runs another bead on the back, thus making it a solid piece. Apparently the Germans in an attempt to speed production just laid the pieces end to end and just ran a bead on the outside, not bothering to weld the middle or back. Is there any chance the Germans started this method in the summer of '44?

[Vanir Ausf B]

<blockquote>quote:</font><hr>Originally posted by rexford:

It would seem from the above that Panther glacis plate armor was fine until mid-1944, and then brittle or reduced effectiveness armor may have appeared on both the Eastern and European Fronts.<hr></blockquote>

OMG. It now appears that CM in not 100% totally wrong after all (only 97.3% wrong).

Anybody seen TSword? This will be a terrible swift revelation for him.

WARNING: The preceeding post may contain sarcasm.

[rexford]

My guess about the 122mm HE round is that AP hits were bouncing off the glacis armor beyond about 650 meters, and HE was a reasonable attempt to disrupt the crew or tank optics. Firing HE at a Tiger or Panther was always a decent tactic if one was cornered, 105mm or larger HE would blow off track pieces or damage wheels with near misses.

The terrific impact from 122mm HE probably would crack some welds and might loosen some glacis plates. I would guess that maybe SU 152's starting hitting Panthers and Tigers with HE during 1943 and some of the damage suggested same tactic might work with 122mm HE.

I will soon be sent some data regarding German weld material. The Germans used high carbon steel which can create welding problems. It appears that the weld material quality may have decreased during the war. Tiger II was supposed to use highest quality weld material. Lower quality weld material may have been used starting January 1944.

American analysis of Tiger and Panther notes brittle nature of welds, hitting with a hammer can bust some welds.

I'll ask about weld shapes on German vehicles, interesting questions.