Sherman 75/L38 penetration: Has BFC’s bibliography improved since CMBB?

[rexford]

Originally posted by Cogust:

What really surprised me regarding armour penetration is the Stuart, it can now penetrate more than 80mm armour at short ranges (88mm@0 at 100 meters) which means that it is capable of knocking out StuGs from the front and Tigers from the side. In CMBO the Stuart was able to penetrate 65-68mm@0 at 100 meters, so it's quite a big improvement penetration wise. The behind armour effect should be smaller though, but they're still very dangerous to medium tanks from the front due to the high ROF.

Suggest that you surround a Tiger at 100m or so with several Stuarts and see if they penetrate the side armor. I matched up a single Tiger against ten M5 Stuarts at 50m to 200m range, and the best result the 37mm APCBC got was a side partial penetration at 60m or so.

StuG III's carry face-hardened armor so 37mm AP will penetrate much less face-hardened armor than homogeneous. However, a panzer with 50mm of face-hardened armor is not going to do too well against 37mm AP at close range due to too thin an armor plate.

By the time Tigers appeared in Nord Afrika Stuarts should be firing alot of 37mm APCBC, which should have less than 82mm homogeneous penetration at 100m.

The April 1943 Stuart data in CMAK shows APCBC penetrating 88mm at 100m, which appears to be too high for either homogeneous or face-hardened armor performance. They should take another look at the 37mm APCBC stats, both the penetration figures and the rate at which the shot loses penetration (penetration looks to high at close range and seems to fall off too fast).

U.S. data for 37mm APCBC shows 78mm at 100 and 59mm at 1000m for homogeneous penetration (1000m penetration is 75.6% of 100m figure), CMAK has 88mm at 100m and 58mm at 1000m (1000m pen is 65.9% of 100m data).

[ January 20, 2004, 06:40 AM: Message edited by: rexford ]

[Cogust]

Oboy, Grog Intervention and I *think* that Rexford supports my gut feeling that the displayed penetration stats for the Stuart is too high.

I can certainly live with Stuart killing Panzer IVs through the turret, that is what I expect from them, but not through the hull. The displayed stats says otherwise though. Should the 37mm really penetrate more than the 2pdr, I thought the Stuart gun were crappier (only used on light tanks) than the 2pdr (used on medium tanks)?

Homogenous vs Face hardened might make the 37mm worse against certain tanks though, I'll have to run a few quick tests when I get home after work.

[flamingknives]

Check the relative weights and M.V.s of the two (37mm and 2pdr) shells. That may give a difference in muzzle energy

[WineCape]

Originally posted by rexford:

By the time Tigers appeared in Nord Afrika Stuarts should be firing alot of 37mm APCBC, which should have less than 82mm homogeneous penetration at 100m.

The April 1943 Stuart data in CMAK shows APCBC penetrating 88mm at 100m, which appears to be too high for either homogeneous or face-hardened armor performance. They should take another look at the 37mm APCBC stats, both the penetration figures and the rate at which the shot loses penetration (penetration looks to high at close range and seems to fall off too fast).

U.S. data for 37mm APCBC shows 78mm at 100 and 59mm at 1000m for homogeneous penetration (1000m penetration is 75.6% of 100m figure), CMAK has 88mm at 100m and 58mm at 1000m (1000m pen is 65.9% of 100m data).

Bolding mine.

Interesting. I thought you guided Charles programming hand in penetration data for CMAK Lorrin? So it *seems* that the Stuart's gun is slightly over modeled in CMAK. Much obliged for the Sherman APCBC gun penetration explanation in CMBB/CMAK.

Question:

Since CM differentiate in general/somewhat between homogenous (mostly in CMBB) and face-hardened armor (mostly in CMAK) penetration capabilities as shown by the penetration stats listed, I assume the CM engine differentiate also when a gun hits homogeneous armor in CMAK and face-hardened armor in CMBB?

Better put: Since only 1 type of penetration stats for a gun is shown (either vs. face-hardened or homogeneous armor) in CMAK or CMBB respectively, can we assume CM simulates also penetration calculations if the "opposite/different" type of armor is being hit than what is generally being shown to us - stat wise - as player in a particular CM game?

Sincerely,

Charl Theron

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[ January 20, 2004, 11:32 AM: Message edited by: WineCape ]

[rexford]

My understanding is that both CMBB and CMAK use two sets of penetration data for each Allied or Russian gun, homogeneous and face-hardened armor stats. And the games differentiate targets by armor type.

So Tiger is homogeneous armor.

PzKpfw IIIG, IIIJ, IIIH, IIIM, IIIN, IIIL are mostly face-hardened, as is PzKpfw IVF2,G,H and a good share of the J.

Panther D has face-hardened hull all around, Panther A early models thru September 1943 have face-hardened front lower hull and side hull.

StuG IIIF and IIIG is mostly face-hardened.

British firing tests and combat reports support the conclusion that when a 32mm face-hardened plate was bolted to a 30mm face-hardened plate they resisted like a single face-hardened plate with 69mm thickness.

So Russian 76.2mm APBC from a T34 or a field gun would penetrate the driver plate on PzKpfw IIIH on half the hits at 750m, and defeat the armor on one-fourth of the hits at 950m, when the gun barrel was aimed directly at the front hull.

And the 30mm/50mm face-hardened plates-in-contact combo on the front of PzKpfw IVG and StuG IIIG would resist Russian 76.2mm APBC hits like more than 80mm face-hardened. U.S. firing tests found that the 30mm/50mm on the front of PzKpfw IVG's resisted like more than a single 80mm plate.

While some have questioned the face-hardened plates in contact theory and conclusions, combat and firing test data supports the theory.

[rexford]

If CMAK uses two penetration stats for each gun, then the 75mm APCBC penetration ranges against 80mm face-hardened and 80mm homogeneous should be radically different.

Tiger has 82mm homogeneous side armor, PzKpfw IVG has 30mm/50mm front hull which probably resists like about 90mm face-hardened in CMAK on the driver plate (slope of about 10 degrees from vertical contributes to the 90mm effective resistance).