Face Hardened Armour

[chuckfourth]

Hi All
Heres a suggestion,
Tarrif's very excelent site lists various gun ammunitions armor penetration values for both rolled armor (RA) and face hardened armor (FHA). I’ve produced a small table from Tarrif’s data that shows the DIFFERENCE in penetration in mm for the same shell when hitting RA and FHA at 100m range. Values in plain type are for shells that can penetrate more mm of RA than FHA, and those in bold are for shells that can penetrate more mm of FHA than RA. I’ve ignored HEAT ammunition (no difference).
The list is not exhaustive but is a pretty good "sample"

100mm D-10S L / 54 and 100mm D-10T L / 54
BR-412 B (Armor Piercing Ballistic Cap) __________________________________________________ ______________5
BR-412 D (Armor Piercing Capped Ballistic Cap) __________________________________________________ ______33
12.7mm M2 HB
12.7mm U.S. M2 AP (Armor Piercing) __________________________________________________ ________________2
12.7mm Vickers
AP W.Mk.I (Armor Piercing) __________________________________________________ _______________________6
122mm D-25S L / 43 and 122mm D-25T L / 43
BR-471 (Armor Piercing) __________________________________________________ ________________________3
BR-471 B ( Armor Piercing Capped )_________________________________________________ __________________17
152mm ML20 L / 28
BR-540 ( Armor Piercing )_________________________________________________ ________________________15
BR-540 B ( Armor Piercing Capped )_________________________________________________ ________________15
15mm BESA
AP W.Mk.Iz ( Armor Piercing )_________________________________________________ _______________________7
25mm SA-L 1937 L / 77
Cartouche mle.1934 P.T. ( Armor Piercing )_________________________________________________ ____________11
37mm M1A2 L / 53.5
APC M.59 Shot ( Armor Piercing Capped )_________________________________________________ _____________5
37mm M3 L / 57 and 37mm M3A1 L / 57 and 37mm M5 L / 53 and 37mm M6 L / 53
AP M74 Shot ( Armor Piercing )_________________________________________________ _____________________19
APC M51B1 Shot ( Armor Piercing Capped Ballistic Cap )_________________________________________________ _4
APC M51B2 Shot ( Armor Piercing Capped Ballistic Cap )_________________________________________________ _4
37mm SA 18 L / 21
OR mle.1935 coiffé ( Armor Piercing Capped )_________________________________________________ _________10
37mm SA 38 L / 33
BR mle.1938 coiffé sans f. ogive ( Armor Piercing Capped )________________________________________________1 0
40mm M1 Bofors L / 60
AP M81A1 Shot ( Armor Piercing )_________________________________________________ ___________________8
40mm Q.F. 2 Pounder Mk.IX L / 50 and 40mm Q.F. 2 Pounder Mk.IXA L / 50
40mm Q.F. 2 Pounder Mk.X L / 50 and 40mm Q.F. 2 Pounder Mk.XA L / 50
AP Shot Mk.I ( Armor Piercing )_________________________________________________ _____________________17
APHE Shot Mk.I ( Armor Piercing High Explosive )_________________________________________________ _____18
APCBC Shot Mk.I ( Armor Piercing Capped Ballistic Cap )_______________________________________________2
45mm 20K Model 1932 L / 46 and 45mm 20K Model 1934 L / 46 and 45mm 20K Model 1938 L / 46
BR-240 SP ( Armor Piercing Ballistic Cap )_________________________________________________ ____________10
BR-240 P ( Armor Piercing Composite Rigid )_________________________________________________ ___________0
47mm SA 35 L / 32
BR mle.1935 coiffé sans f. ogive ( Armor Piercing )_________________________________________________ _____10
57mm Q.F. 6 Pounder Mk.II L / 43 and 57mm Q.F. 6 Pounder Mk.III L / 43
AP Shot Mk.III ( Armor Piercing )_________________________________________________ ___________________20
APC Shot Mk.VIII ( Armor Piercing Capped )_________________________________________________ __________0
APCBC Shot Mk.IX ( Armor Piercing Capped Ballistic Cap )_____________________________________________7
APDS Shot Mk.I ( Armor Piercing Discarding Sabot )_________________________________________________ ____0
57mm Q.F. 6 Pounder Mk.IV L / 50 and 57mm Q.F. 6 Pounder Mk.V L / 50
AP Shot Mk.III ( Armor Piercing )_________________________________________________ ___________________28
APC Shot Mk.VIII ( Armor Piercing Capped )_________________________________________________ __________0
APCBC Shot Mk.IX ( Armor Piercing Capped Ballistic Cap )_____________________________________________3
APDS Shot Mk.I ( Armor Piercing Discarding Sabot )_________________________________________________ ____0
57mm ZIS-2 Model 1941 L / 72.9 and 57mm ZIS-2 Model 1943 L / 73
BR-271 ( Armor Piercing )_________________________________________________ __________________________7
BR-271 N ( Armor Piercing Composite Rigid )_________________________________________________ __________0
75mm M2 L / 31
AP M72 Shot ( Armor Piercing )_________________________________________________ _____________________12
APC M62 Projectile ( Armor Piercing Capped Ballistic Cap )______________________________________________9
75mm M6 L / 39
AP M72 Shot ( Armor Piercing )_________________________________________________ _____________________16
APCBC M62 Projectile ( Armor Piercing Capped Ballistic Cap )__________________________________________11
APC M61 Projectile ( Armor Piercing Capped )_________________________________________________ __________1
75mm Q.F. Mk.V L / 36.5
APC M62 Projectile ( Armor Piercing Capped )_________________________________________________ __________1
76.2mm F-32 L / 42 and 76.2mm F-34 L / 42 and 76.2mm ZIS-3T Model 1942 L / 52
76.2mm ZIS-3T Model 1942 L / 52 and 76.2mm ZIS-5 L / 42
BR-350 A ( Armor Piercing Ballistic Cap )_________________________________________________ _____________1
BR-350 B ( Armor Piercing Ballistic Cap )_________________________________________________ _____________1
BR-350 P ( Armor Piercing Composite Rigid )_________________________________________________ __________0
76.2mm KT-28 L / 16
BR ( Armor Piercing )_________________________________________________ _____________________________5
76.2mm L-10 L / 24
BR ( Armor Piercing )_________________________________________________ _____________________________9
76.2mm L-11 L / 32
BR-305 B ( Armor Piercing Ballistic Cap )_________________________________________________ ____________2
76.2mm PS-3 L / 20
BR ( Armor Piercing )_________________________________________________ ____________________________7
76.2mm ZIS-3 Model 1941 L / 42
BR-350 A ( Armor Piercing Ballistic Cap )_________________________________________________ ____________1
BR-350 B ( Armor Piercing Ballistic Cap )_________________________________________________ ____________1
76mm 3 Inch M5 L / 50 and 76mm 3 Inch M7 L / 53
AP M79 Shot ( Armor Piercing )_________________________________________________ ___________________19
APC M62 Projectile ( Armor Piercing Capped Ballistic Cap )____________________________________________3
76mm Q.F. 17 Pounder Mk.II L / 55 and 76mm Q.F. 17 Pounder Mk.III L / 55 and
76mm Q.F. 17 Pounder Mk.IV L / 55
AP Shot Mk.III ( Armor Piercing )_________________________________________________ __________________29
APC Shot Mk.IV ( Armor Piercing Capped )_________________________________________________ ___________7
APDS Shot Mk.I ( Armor Piercing Discarding Sabot )_________________________________________________ ___0
85mm D-5S L / 52 and 85mm D-5T L / 52 and 85mm Model 1939 L / 52 and
85mm S-53 L / 52 and 85mm ZIS-53 L / 52
BR-365 ( Armor Piercing )_________________________________________________ _________________________3
BR-365 K ( Armor Piercing Cappped )_________________________________________________ _______________11
BR-365 P ( Armor Piercing Composite Rigid )_________________________________________________ __________0
87.6mm Q.F. 25 Pounder Mk.I L / 28 and 87.6mm Q.F. 25 Pounder Mk.II L / 28
AP Shot Mk.I ( Armor Piercing )_________________________________________________ ___________________8
90mm M3 L / 52
AP M77 Shot ( Armor Piercing )_________________________________________________ ____________________17
APHECBC M82 Projectile ( Armor Piercing High Explosive Capped Ballistic Cap )_____________________________9
APCR M304 Shot ( Armor Piercing Composite Rigid )_________________________________________________ ___0
94mm Q.F. 3.7 Inch Mk.II L / 50
Armor Piercing Mk.II ( Armor Piercing )_________________________________________________ _____________15

In the game FHA is treated the same as RA.
Treating RA and FHA armor the same means that from the list above;
On a gun by gun basis 17 guns have less penetration than they should have vs FHA and 41 guns have more penetration than they should have vs FHA
Looking at AP shells rather than guns, 9 shells have less penetration than they should have vs FHA and 36 shells have more penetration than they should have vs FHA
As a general indicator, treating FHA the same as RA means tanks sporting FHA miss out on about 418mm of armor protection (ie sum of ammunition penetrations in plain type), but gain an extra 76mm of armor protection (ie ammunition penetrations in bold type). That’s about a 5.5 to 1 ratio. Put another way FHA vehicles miss out on 342mm (418-76) of armor protection.

So I think it would be fair to suggest that vehicles sporting FHA could get a +1 value for any FH surfaces.

I should point out that neither treating FHA and RA the same or giving FHA a +1 bonus is correct, However giving FHA armour is I think the lesser evil. or closer to reality.
Note the 17 guns (with less penetration than they should have) is a bit inflated as it includes different models of the same gun. If we ignore models and just look at guns we get 8 vs 24 (ie 1:3) rather than 17 vs 37. From this list the guns that have a shell that performs better against FHA are the Russian 122 and 152; British 2 pdr, 6 pdr and 25 pdr; the American 75 M2, 75 M6 and 76 M5, the remaining 24 guns perform worse against FHA

I don’t think giving FHA +1 would particularly disadvantage these 8 guns as their penetrations are above or well above the largest FHA increase I can find, which is the front turret of pz IV which would go from 5 to 6 (and the vast majority of FHA plates are much thinner, 1's,3's etc). The guns mentioned have I think penetrations (@ 50m) of 17, 13, 7, 11, 10, 8, 10 and 12.

For 30 of the shell types that can currently penetrate more FHA than they really could the difference shown above is 5mm or better, for 21 the difference is less than 5mm or 0. For the lower difference values (ie 0's would lose a point of penetration vs FHA) you could say the change is also modeling FHA's better ricochet performance and FHA's ability to shatter some rounds.

Giving FHA +1 changes the overall balance from 418 vs 76 to 118 vs 300 moving the ratio from 5.5:1 to 1:2.5 (now in favor of FHA). A "fairer" result ie closer to 1:1. Overall the 1:2.5 ratio equates to an extra “unwarranted” bonus 182mm of armor. Again this can be justified using the bounce and shatter "excuse" and that most face hardened armour plates defence values are so overmatched by the guns in question's penetration values it doesnt matter.

Please excuse any adding mistakes they are minor.

Pz 4 has FHA panels and I believe sdkfz 231 and 232 also came in face hardened armor. Does anyone know any other vehicles that had face hardened armor?
See
http://ourworld.compuserve.com/homep...s/Specs-02.htm
this site gives all FHA specs for pz 4
Best Regards Chuck

[PopskiPPA]

IIRC (I'm working from memory) the Russians and the western allies used different anti-armor ammo. One was better against face-hardened armor, the other against rolled homogenous armor.

The Germans reacted by producing different armor for the western and eastern front.

So it's not a question of changing a penetration-value, you'd have to double the number of german armored vehicles. Later in the war one can imagine the Germans would use the armor that was at hand at the time, ending up with a mix of RHA and FHA on the same front, even on the same vehicle.

As I said, I'm working from memory (reading to much stuff), so please correct me if I mixed up something.

[chuckfourth]

Hi Popski,
Thanks for your interest.
I have a couple of points
If you look at my table or possibly Tarrifs original you will see that the Russians, Americans and British all had guns that fired shells that were better at penetrating FHA and guns that fired shells that were better at penetrating RA. So there wouldnt be much point in making different armour types for different fronts every front was the same in this regard. Also from the Italian campaign onwards Hitler (much to the consternation of his generals) was in the Habit of moving whole corps from one front to the other which would cause further trouble.
Also
Im not suggesting a change in penetration values but a change in armour values, ie plates of FHA gets +1.
Best Regards Chuck.

[noxious]

Many tanks had FH armour, often those with thinner armour like the US M3 halftrack. There is also differences in armour hardnees without FH. Some being very hard and some being very soft. Different ammunition will react differently to different RHA hardness as it will to FH.

Also, why should tank benefit in game against all guns when FH only gave benefit to some ammunition fired by the same gun?
6-pdr British gun firing APCBC penetrated more FH than RHA but same gun firing AP penetrated more RHA than FH. Why should British gun be punished?

I think you play the wrong game. Play the matrix game, that has much more complicated penetration program that will make you happy.

Nox

[pdoktar]

Isn´t rolled homogenous armor a basic given armor thickness value? As there are not softer and harder RHA but only RHA as a universal penetration quotient? So laying harder and softer materials after each other in a given pattern would constitute a RHA value.

So RHA has only one hardness when it is calculated as a universal armor thickness of RHA of given plate thickness and materials.

[chuckfourth]

Hi Nox
You ask
"Also, why should tank benefit in game against all guns when FH only gave benefit to some ammunition fired by the same gun?"

As you correctly point out most FH armour is thin, in the roughly first half of the war before the advent of the ammunition types and calibres that had improved penetration against FH armour. Giving FH armour +1 doesnt disadvantage any guns.
As the shells and calibres that have improved penetration values against FH armour begin to appear, in the vast majority of cases the penetration value of the weapon is so much greater than what the thin FH armour defence value is, it hardly matters +1 or not, while against the remaining, majority of shells/calibres modeling becomes more accurate with +1.
But to answer you question specifically,
because
Currently all FH armour is disadvantaged against most regular ammunition types. This is incorrect. As Ive tried to explain above it is less incorrect to give FH armour +1 than to give it the same value of RHA, which is also "wrong" because against most ammunition types FHA performs better than RHA.
For your example,
"6-pdr British gun firing APCBC penetrated more FH than RHA but same gun firing AP penetrated more RHA than FH. Why should British gun be punished?"
I would ask
Why should the 6 pdr AP shell be given bonus penetration against FH armour as currently modeled?

Best Regards Chuck