Why Germans Stayed with Face-Hardened Armor So Long

[rexford]

1. It appears that the Germans were unaware of what blunt nose APBC could do against face-hardened armor. The Germans publish and use Russian penetration figures for comparisons against homogeneous armor and never realize it is against face-hardened armor.

This is odd, cause a German Intelligence report on SU 85 clearly states that the penetration data is calculated against face-hardened armor, yet other German documents use the same figures for penetration range analysis vs homogeneous armor on Tiger and Panther.

The Germans use the face-hardened penetration of 122mm AP to determine that the round cannot penetrate Panther glacis at any range or angle. Try 700m based on combat experience against good quality armor.

The Germans appear to have missed the implications of blunt nose APBC. In a similar vein, the British did not realize the Germans were using face-hardened armor till well into 1942, at which point they started to look at armor piercing caps.

That's alot of years of PzKpfw III and IV with face-hardened armor before the British wake up.

Sometimes one completely misses the boat when it comes to analyzing armor and penetration (did I leave myself vulnerable on that one?).

2. 80mm face-hardened on PzKpfw IV was good at stopping 45mm and 76.2mm APBC and AP, and both fired rounds without armor piercing caps. And it was a "given" at the time that an armor piercing cap was needed to defeat face-hardened armor at good ranges.

3. Based on my calculations 45mm AP penetrates less face-hardened than homogeneous, and the same holds for 76.2mm AP. And 45mm APBC penetrates more homogeneous armor than face-hardened at close range.

So face-hardened armor would be better against 45mm rounds, which constituted alot of the Russian anti-gun inventory.

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Interestingly, there is a sentence on the John Salt site, the penetration data document, where 28/20 Gerlich tungsten ammo penetrates 76mm of medium hardness homogeneous armor at 100 yards but almost makes it through 87mm of face-hardened plate. 17 pdr APDS penetrates 231mm of face-hardened armor at 1000 yards and 30 degrees, and penetrates less homogeneous armor at the same angle and range.

So tungsten ammo looks better against face-hardened than homogeneous, which makes sense since tungsten rounds are harder than face-hardened armor which reduces the ability of that armor to break up the projectile hit. And once the face-hardened surface fails the armor loses much of its resistance.

Russian APCR may have been more effective against face-hardened armor than homogeneous.

If the preceding is true, are the published Russian stats for APCR penetration against face-hardened or homogeneous armor? And should they be adjusted for either type of armor?

[Fishu]

FHA worked well against early 2pdr

[Meach]

Ok, Meach the noob with yet another dumb question..here goes... AP is armour piercing, APBC is AP ballistic capped..and so on..but what does it all mean? APCRBC is that AP core, rigid ballistic capped? Oh me head hurts now!! Someone please explain to me the abbreviations and how something blunt can penetrate steel?

Oh and another thing..face hardened, homogenous? Is that different types of armour plate?

Edited to ask yet another question.

[ April 30, 2003, 06:13 AM: Message edited by: Meach ]

[rexford]

Originally posted by Meach:

Ok, Meach the noob with yet another dumb question..here goes... AP is armour piercing, APBC is AP ballistic capped..and so on..but what does it all mean? APCRBC is that AP core, rigid ballistic capped? Oh me head hurts now!! Someone please explain to me the abbreviations and how something blunt can penetrate steel?

Oh and another thing..face hardened, homogenous? Is that different types of armour plate?

Edited to ask yet another question.

Sorry for the headache. And the unexplained abbreviations.

AP is an armor piercing round that is shaped for penetration effectiveness but has a poor shape in terms of air resistance. AP is good against medium hardness homogeneous armor (same hardness all the way through the plate thickness), but loses velocity and penetration somewhat quickly with range.

AP stinks against face-hardened armor, where a thin surface layer is much harder than the steel projectile nose. Face-hardened armor tends to damage the nose of AP rounds, significantly decreasing the penetration capability.

APBC is a blunt nose Russian round that penetrates more face-hardened armor than homogeneous at 76.2mm diameter. The APBC is somewhat soft but it has very good impact resistance or toughness. The ballistic windscreen cap on APBC cuts air resistance very nicely.

So 76.2mm APBC penetrates face-hardened armor very well by suddenly unloading a tremendous impact on the hard surface layer, and APBC penetrates homogeneous plate by tearing the armor around the outside of the impact area. I've seen pictures of blunt nose ammo penetrating homogeneous plate and it really does tear the armor and pushes a plug of steel out through the plate.

Is 76.2mm APBC a really good idea?

A T34 firing 76.2mm APBC at 662 m/s can penetrate about 72mm of homogeneous armor and 76mm of face-hardened armor at 500m.

A Sherman firing 75mm APCBC at 619 m/s can penetrate 81mm homogeneous and 95mm face-hardened at 500m. APCBC is an armor piercing round with a ballistic windscreen to cut air resistance and an armor piercing cap which absorbs the large impact when rounds hit the hard face-hardened layer.

The Sherman round, fired at a lower velocity, is better in many ways.

Armor piercing caps are a solid layer of steel that overlays the projectile nose and spreads the impact over a bigger area, and the caps even have an air space over the projectile nose to further protect that sensitive spot.

One of the big advantages of APBC over AP is that the flat nose tends to dig into homogeneous armor when it is sloped, which counters the ricochet effect. So APBC is very good against sloped plate.

122mm AP penetrated the Panther glacis at 700m during initial combats, 122mm APBC would penetrate at 1500m due to the flat nose surface.

APBC does not have a total flat nose, the area that is flat ranges from 20% of total diameter on 122mm APBC to 40% on 76.2mm APBC. American tests with flat noses that made up about 80% or more of the diameter showed that those rounds tended to break up against armor thicknesses greater than the projectile diameter.

[Meach]

No need to apologise for the headache..I get confused way too easy..

Gonna take some time and digest this info, maybe print it out cos I am interested in the technical side of blowing tanks to bits I just don't have any knowledge of the physics involved. Thank you for taking the time to post, deeply appreciated.