Tiger-II front glacis vs AT guns

[delcyros]

Even if it is a few weeks behind the discussion, I submit some aspects to penetration of the King Tigers frontal 45* degrees inclined 150 mm plate (upper part, face hardened Q=0.98, elongation=13%).
-It is estimated that only core hits (neglecting longitudinal impact angles) counts, hits with longitudinal impact angle will have a worser time to defeat this plate-

*the actual inclination is 50 degrees but I take light "downshooting" into account to make penetration easier
------------------------CONTENDERS------------------
type--ammo---size-----shellweight-muzzle vel.---examples
SU:
D5----APCBC--85 mm---9,2Kg----792 m/s------T-34/85, SU-85
D10---APCBC--100 mm--15,8Kg---880 m/s------SU-100
D25---APCBC-125 mm---24,9Kg--780 m/s------JS-II
US:
M7----APCBC--76,2mm-7.0 Kg-----793 m/s.----Sherman (typical)
M3----APCBC--90mm---10.94 Kg---808 m/s.----Pershing
Britain:
QF75--APCBC--75mm---6,8 Kg----620 m/s------Cromwell
17pdr--APCBC--76,2mm-7,7 Kg----900 m/s------Comet, Sherman Firefly
Germany:
KWK42-APCBC-75mm---6,8Kg------893 m/s.----Panther
KWK36-APCBC-88mm---10,2 Kg----773 m/s.----Tiger-I
KWK43-APCBC-88mm---10,2 Kg----1000 m/s.---Tiger-II, Elefant
Pak44--APCBC-128 mm-28,3 Kg----920 m/s.----Jagdtiger
--------------------------------------------
US :

M7) - minimum striking velocity needed for full penetration exceeds muzzle
velocity (>1200 m/s), no penetration ever possible
M3) - minimum striking velocity needed for full penetration exceeds muzzle velocity (>1200 m/s), no penetration ever possible

Britain:

QF 75)- minimum striking velocity needed for full penetration exceeds muzzle velocity (>1200 m/s), no penetration ever possible
17pdr) - minimum striking velocity needed for full penetration exceeds muzzle velocity (>1200 m/s), no penetration ever possible

SU:

D5 - minimum striking velocity needed for full penetration exceeds muzzle velocity (> 1200 m/s), no penetration ever possible
D10 - minimum striking velocity needed for full penetration exceeds muzzle velocity (~1140 m/s), no penetration ever possible
D25 - minimum striking velocity needed for full penetration exceeds muzzle velocity (~ 987 m/s), no penetration ever possible

Germany:

KWK42) - minimum striking velocity needed for full penetration exceeds muzzle velocity (>1200 m/s), no penetration ever possible
KWK36) - minimum striking velocity needed for full penetration exceeds muzzle velocity (~1062 m/s), no penetration ever possible
KWK43) - minimum striking velocity needed for full penetration exceeds muzzle velocity (~1062 m/s), no penetration ever possible
PAK 44) - Full penetration achieved. Minimum striking velocity needed: 908 m/s. Shell suffers nose shatter. Shell suffers lower body broken up at impact, rendering the projectile ineffective. The gun will achieve full penetration at 0-170 yrds distance only.

CONCLUSION: Other than via pure luck (it went through the optics, the welding is poor, etc.) or by repeated hits, no ww2 tankgun will defeat the Tiger II glacis plate, even from point blanc range. Only the 128 mm Pak 44 of the Jagdtiger has a chance to do so. The closest tank gun to achieve this is the Kingtigers 8.8cm KWK 43, only 63 m/s (mostly thanks to it´s superior AP-cap). striking velocity are missing to achieve full penetration. The soviet D 25 misses 207 m/s striking veloicty and the soviet D 10 missed it by 260 m/s (interesting. I always believed the D-10 would be better than the D-25). However, at these velocities, the projectile will always suffer full shatter, rendering the small cavity charge useless.

[syscom3]

Delc, interesting information.

Was the US 90mm gun as specified, the same gun as used on the Pershing tank?

[Soren]

Originally Posted by syscom3

Delc, interesting information.

Was the US 90mm gun as specified, the same gun as used on the Pershing tank?

Yes, its the 90mm M3, which is the gun on the Pershing.

[delcyros]

Absolutely.

Here some armoured vehicles (sorry for simplification) to use the guns from above:

SU:
D-5: T-34/85, KW-85, Su-85
D-10: T-34/100 -prototype, Su-100
D-25: JS-2

US:
M3: Pershing
M1/M7: Sherman

Britain:
QF75: Cromwell
17pdr: Sherman Firefly, Comet

Germany:
KWK36: Tiger I
KWK42: Panther
KWK43: Tiger-II / (same gun as Pak 43 used in Elefant)
Pak44: Jagdtiger

Does anyone out here has informations about the exact shellweightfor the soviet guns? I do used approximations for them but there might be an error up to 8% in shellweight (even in the best case = firing superheavy 65 lbs shells, excludes them from reaching striking velocity to defeat the front glacis plate).

[Soren]

D-5, APCBC: 9.2 kg
D-10, APCBC: 15.8 kg
D-25, APCBC: 24.9 kg

[delcyros]

Thanks Soren. I fixed the points. Nothing really changed, the D-10 peformance improves but still is far away from defeating the glacis plate.

[Soren]

Ur welcome Delcyros.

[Twitch]

Delcyros- Got no idea why anyone would imagine the Tiger could be defeated by any available guns in the field at the time. There are simply too many accounts of ordnance bouncing harmlessly off them.

[delcyros]

It has been matter of discussion some weeks earlier. Based on post war evidence I read that the later SU guns (D10 and D-25) could defeat the glacis plate (there exist a photo showing a defeated Tiger-II glacis). I had to collect much information on specific shell and AP-capdesign and armour properties to perform these computations. Now I am pretty sure that the plate was defeated by repeated heavy shell hits from very close range and not by a single hit.

[plan_D]

You could have just asked me that, delcryos. If it's the same King Tiger that I'm thinking of, it was turret #502 and was captured by the Russians and used for extensive testing. It was shot repeatedly by various Russian cannon, but mostly by the A-19 122mm at all ranges. I haven't got the images, but they do exist of the King Tiger's plate and it is punctured but you can see dent marks all around the hole. Clearly, the King Tiger had been shot over and over again.

[delcyros]

Thanks for clarification, Plan_D!
I believe, we have the same sample in mind.

[Hop]

Britain:
QF75--APCBC--75mm---6,8 Kg----620 m/s------Cromwell
17pdr--APCBC--76,2mm-7,7 Kg----900 m/s------Comet, Sherman Firefly

Couple of points. Firstly, I don't think the Comet carried the 17 pdr, afaik it carried the detuned version, the 77mm.

Secodnly, why no apds for the 17 pdr? It was widely used post D day, and offered far superior performance (over 1200 m/s, iirc)

[delcyros]

I still have my problems with APDS and APCR calculations. Big obstacle are the design specifications for them avaiable in the net. I know about the performances, only. However to compute with some degree of reliability I need more specific informations, such as CAP-shape datas, cross sectional density, rate of deceleration, Brinell hardness of the projectile nose / APcapnose (very important if You want to penetrate any face hardened type of armour) and core diameter for sub calibre and / or rigid core ammo. I could compute approximations for them but the differences are significant, so I leave it until I get the datas fixed for them.
Personally, I cannot imagine, how a APDS shell may defeat the glacis. At these velocities the shell will always suffer full shatter as well. The inclination of the glacis makes it to difficult to defeat with APDS at least for a 76,2 mm gun.
It still remains interesting if the subcalibre may offset the disadvantages in impact weight. Theoretically spoken, halving the weight and increasing the impact velocity by 50% remains the same in terms of armour penetration (with all other factors beeing identic). However, the subcalibre delivers some additional benefit, but the question remains if this would reduce the +300 m/s minimum striking velocity to a point to defeat the glacis.

[Soren]

Well considering that the 17pdr's APDS rounds would often shatter on impact with the Tiger Ausf.E's frontal armour, even at close ranges, I think we can be pretty sure that it had no chance what so ever of penetrating the Tiger Ausf.B's frontal armour.

[schwarzpanzer]

This is very interesting delcyros, the results are interesting thankyou!

Here is what you are looking for:

http://www.battlefield.ru/index.php?...id=123&lang=en

Please be aware that the Soviet 122mm didn't work by penetration, it used other kinetic factors like internal spalling and mechanical shock etc.

You can actually use mechanical shock to start an engine too! (Cockney screwdriver).

Also the test example was of poor quality.

It was hit a number of times, but if you're going to say 'armour failure' then you cannot discount 'work hardening'.

Also if plunging fire was used against the glacis (the D25 was a howitzer after all) the damage would be more severe, though you have mentioned this.

Also if the MG ball mount or seams were hit...

It doesn't look like you've counted skate angle, this would make the 17pdr innefective.


delcyros, would it be possible for you to calculate the max range the Tiger II's turret front can be penetrated by the Soviet 100mm?