The aftereffect of US 37mm AP shot seems too high in the CMBN

[Erwin.Rommel]

I repeatly tests the M5A1 VS IV(IV holds fire),the range is about 200-300m.the result:50mm turret front is no need to discuss.For the hull,37mm APCBC can not penetrate lower front and upper front of IV in the given range,the rounds that hit the superstructure front of IV can achieved penetration or partial penetration(mostly the partial),above results has no problem.My real concern is,during these repeat tests,just 2-3 penetrations on the superstructure front leads to a "KO" .As we know the 37mm APCBC shot has no explosive charge,these small calibar rounds don't have much aftereffect when penetrated about 80mm Armor.I created the same tests in CMAK,almost all the rounds that penetrate hull(even the turret) result in a "no serious damage",and the IV is still alive after been penetrated many times.So,Is the aftereffect of 37mm AP shot been modelled too high in CMBN?

[StellarRat]

No. It seems reasonable to me.

[Erwin.Rommel]

No. It seems reasonable to me.

Then the results in CMAK seems unreasonable to you?

[George MC]

Hhmm - you're comparing two games - which one is right ya think?

Maybe CMAK had it wrong?

[Amizaur]

So 37mm AP seem to be just as effective post-penetration in disabling tanks and their crews like German 88mm or 75mm shells. But I believe it's not 37mm AP that is overmodelled (well, maybe a little, considering those are marginal penetrations), rather the effectivenes of 88mm and 75mm shells is undermodelled.

Erwin, could you please use a Panther in the same test and settings, again this PzIV (chose Blue on Blue engagement) and check if it's more or less effective ? What number of penetrations from Panther's 75mm high-energy APCBC-HEs is needed on average, to disable this PzIV in comparison to Stuart's 37mm APs ?

[akd]

So 37mm AP seem to be just as effective post-penetration in disabling tanks and their crews like German 88mm or 75mm shells.

Terminal effects are quite complex, but this is certainly exaggeration.

[Battlefront.com]

Over generalizations don't do anybody any good. Let's remember that the 88 fired from the Tiger 1E is very different than the Tiger II and Jagdpanther. Also, the 75mm from a Panther is very different than the 75mm from a PzIV. And what is being struck is equally important.

Because CMx2 allows Blue vs. Blue and Red vs. Red, it is possible to do side by side comparisons. You can fire a 37mm round at the front of a PzIV and then fire a PzIV's 75mm against a PzIV. This can help make reasonable apples to apples comparisons. Though that's just a start.

Steve

[Erwin.Rommel]

So 37mm AP seem to be just as effective post-penetration in disabling tanks and their crews like German 88mm or 75mm shells. But I believe it's not 37mm AP that is overmodelled (well, maybe a little, considering those are marginal penetrations), rather the effectivenes of 88mm and 75mm shells is undermodelled.

Erwin, could you please use a Panther in the same test and settings, again this PzIV (chose Blue on Blue engagement) and check if it's more or less effective ? What number of penetrations from Panther's 75mm high-energy APCBC-HEs is needed on average, to disable this PzIV in comparison to Stuart's 37mm APs ?

I just tests the Panther vs IV as you requested.During all the 20 times I tested,Just one APCBC from panther is needed to knock out the IV.whatever the places the rounds hit,the rounds not only penetrate the front armor but also go through the interior of the tank,then penetrate the rear armor of the tank until hits the ground or fly to the outside of the map.

[Amizaur]

Well I just made the same thing. Got similar results .

88mm from Tiger is much more effective in disabling a PzIV than 37mm AP.

I did also your test, so 37mm AP against PzIV turret front (I placed them in a way that only the turret was visible.

BTW it was not an easy task, what would be nice in the editor is a stone or brick wall that is tall just enough to hide a tank's hull. Currently the "wall" is much too low, and the "tall wall" is as high as the tank itself. Would be nice to have a wall that is in between.

My results of 37mm AP against PzIV are different than yours. In my tests, let me check...

on 36 penetrations of the PzIV front turret from 200m, results were:

28 times no one was hurt (77% of penetrations)

8 times there was one casuality (22%)

2 times the tank became destroyed (6%)

With such percentages, it's quite probable to see several penetrations in a row without anyone being hurt.

What is strange: after several front turret penetrations, multiple systems of PzIV were usually devastated (optics, radio, weapon controls, whatever), but the crew unhurt. They seem to have some kind of splinter-proof vests on them . They also doesn't seem too nervous about shells penetrating the turret.

The turret is much smaller than the hull, there are three human bodies packed around the gun, it seem questionable that 37mm projectiles just fly trough not harming anyone in almost 80% of cases. They would be injured at least. If injured is not counted as "casuality" in tanks, then particular crewmembers that were in proximity of the shell path, should have high chance of being at least inoperable for some time (let's say 10-30 seconds) after penetration. That would simulate the shock of being wounded (wounds to the face, hands, eyes) and time to recover or take quick care about the wounds.

On the other hand, in three cases were the PzIV front hull was hit with 37mm AP, those were partial penetrations with armor spalling, the effect on crew morale was much higher - two crews went panicked and evacuated at once the undamaged vehicles, one crew went rattled. In one of those three partial penetrations, a crewman died because of spalling.

Seem "partials" with spall are more dangerous to the crew than full penetrations. And full penetrations should also cause lot's of armor splinters anyway.

The effect on crew morale of penetrating (full or partial) the hull, SEEMS to be higher than effects of hitting or even penetrating the turret.

I would say, that average density of crewmen/m^3 is higher in the turret than in the hull, so turret penetration should have worse consequences for a crew's health (at least the gunner, commander and loader) than hull penetration. On the other hand, hull penetration have much higher chances of causing ammo/fuel fire or explosion, or penetrate all the way to the engine and disable/set it on fire.

Next I switched the Stuarts for Tigers. The results were much, much serious for PzIVs.

Didn't do much testing because it was obvious than effect after 88mm penetration is much greater.

On 16 penetrations of PzIV front turret from PzVI Tiger, on 200m, results were as follows:

4 penetrations resulted in explosion and instant death of all crewmembers (25%)

1 penetration caused 4 causalities (6%)

3 caused 2 casualities (19%)

7 caused 1 casuality (44%)

4 didn't harm anyone (25%)

4 penetrations caused tank being "destroyed" without killing anyone or damaging anything (25%)

Every shot went completly trough, hitting dirt behind the PzIV. Even those which hit the hull (not counted), they just went trough, like there was no engine on the way.

So chance for tank explosion (25%) was about the same as no one being hurt (25%) after massive high velocity 88mm shell penetrated both front and rear of the PzIV turret, most likely detonating the burster inside. Chances of someone being killed were almost 70%, chances to die for a turret crewmember were almost 50% (not counting the total explosions).

I would say, it's reasonable that there is 25% chance of no one being killed, IF somehow the almost certain crew shock and injures were simulated, for example by disabling those crew members for some time (the status of this crewmember could show text "injured" or "disabled" or "shocked" or whatever you call it, it would be disabled for 10-30 seconds and then return to normal function. In contrast to a current "casuality" which is killed or seriously injured and doesn't return to function, but rather disappears from the crew list.

Like it is now, I didn't see see much of "shock" after penetrations (the ones that didn't cause casualities, or even those which caused) - the (remaining) crewmembers just continued their work - aim, reload and return fire. I've seen rattled crews that stopped "aiming" and went to "spotting" for some time, then returning to "aiming and reloading" so normal operations. I also seen red "panicked" crews normally aiming, reloading and returning fire.

Is the morale status valid for the commander, or the whole crew ? Does the "Panic" means the commander is in panic, or whole crew is ?

I would also like to ask, what is the difference between "Destroyed" and "Knocked out" status? Sometimes a penetration causes tank to be "Destroyed" or "Knocked out" - even if it didn't kill anyone or make any visible damage of tank systems. I understand this as tank as a whole being non-operative, but what's the difference between the two ?

Hmm - I wonder, how the crew of the firing AI tank knows, the tank has "destroyed" status so they don't waste more rounds on it ? The tank that doesn't burn, the crew is inside, but somehow the enemy knows it's "destroyed" and not fire on it anymore . IIRC in CMx1 crews were firing as long, as the enemy tank either was set on fire or the enemy crew was seen evacuating. Seems in CMBN they stop firing when they "destroy" or "knock-out" the enemy tank... How do they know ? .

Overall, my conclusion - if based only on results on this, little test - would be, that the chances of tank being knocked out, or destroyed or damaged are little low or maybe even ok for me. Hard to tell, no hard data, just feeling what's "right" or what's "wrong" and if the game outcome is similar than those from tanker's memoirs. Chances of crewmembers being killed or seriously wounded are either ok, or maybe little low.

But the effects of penetrations (especially APHE ones !!!) on crew morale are undermodelled. They should more easily panic and try to evacuate, or become shocked and non-responding. Currently even penetrations that killed some crewmembers, don't have much influence on the remaining crew. There is also no (visible) modeling of lighter wounds and temporary incapacitating of crewmembers - in cases they didn't die, but were lightly injured or stunned by shrapnels or burster detonation. And it's hard to imagine for me than an 40-50g HE burster going off inside a tank, could not stun oreveryone for a while, injure, not make thinking about getting out from this smoke filled steel coffin. Not necessarily the burster would kill everyone, but psychological effect should be serious IMHO.

Steve said the Tiger 1E shell is different from Tiger 2/Jagdpanther shell, and short L48 75mm shell different from long L70 75mm shell. Not sure what he meant.

The projectiles are very similar or even the same. The short and long 75mm guns fired the same shell, I mean same construction and burster size, maybe they were littlie different in hardness, not sure. The late 8,8cm L56 and 8,8cm L71 fired again very similar shell, late L56 shell had IIRC same burster size like L71 shell, again they were maybe different in steel hardness or some details. Early L56 (flak) shells had different, much larger bursters, but they were not used in this timeframe I believe....

What was VERY different between shorter and longer guns, was of course the kinetic energy - pre and especially post penetration . There is no question about this. But on every effective penetration, where the shell remained intact and fuse was not broken in the process, the HE burster should go off causing some nasty effects on the crew. Additional high kinetic energy could only make it worse.

The 75mm shells had quite small HE burster, just 17g of something-like C4, in comparison to 64g in 88mm shells. But even such small burster, should I think cause distinct psychological effect on the crew, by means of going boom, flash, filling the inside with smoke, producing some shrapnel. I personally would NOT want to be anywhere close to 17g of hexogene going off in steel case, especially would not want to be in a closed, confined space. I would be glad, if a body of another crewmember was between me and the detonation point......

The effect of large, 88g burster could be disastrous in a small buttoned tank, nearly 100g of hexohene in closed space probably generates overpressures levels that are dangerous for life. I wonder if there are first-hand relations of how it feels to be in tank penetrated by 88mm shell with working fuse. Probably what would they tell, would be that thety just saw flash and lost consciousnes, next what they remember is they wake up in smoke filled tank and get out from there...

On the other hand, 17 pounders didn't have any burster and were still effective in killing German tanks. Still able to kill the crew, or made it to abandon the tank, or even detonate the ammo/fuel sometimes...

That's why I'm not very happy, seeing Shermans (or Panthers) having front turret penetrated by 88mm shell, with whole crew ok and able to do their work like nothing happened. Or even one crewmember being killed, but the rest of the crew not impressed and still operating the tank. You don't have to kill them everytime, but at least stun them a bit !

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Some rough estimates done on different day for different forum:

Panther's 75mm shell with 925m/s muzzle velocity:

Chemical energy of the HE burster (~23g of TNT) - 0.11MJ

kinetic energy of the shell at the muzzle - 2.9MJ (26 times higer)

at range of 500m - 860m/s and 2.5MJ of kinetic energy (~ 150mm of penetration potential)

after penetrating 80mm of armor - 530m/s left and 0,97MJ of KE (should be less as the piercing cap was left outside, so the mass is not less than 6.8kg now).

throwing into the tank ~2,8kg of armor fragments (cylinder 80mm long and 75mm in diameter)

if assume speed of fragments 2/3 of projectile speed, we get 350m/s and 0,17MJ of KE of those 2,8kg shrapnel fragments.

HE burster goes off adding 0.11 MJ of heat, boom, flash, overpressure, some more fragments and smoke.

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KE of 88mm L56 shell fired at 780m/s - 3,1MJ

KE of 88mm L71 shell fired at 1000m/s - 5,1MJ

energy of 88mm shell HE burster (~86g of TNT) - 0,4MJ

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[Magpie_Oz]

Just as a thought how many of the MegaJoules of energy of the round is used in penetration of the armour? That's going to have a big impact (pun intended) of the behind armour effects.

[akd]

I would also like to ask, what is the difference between "Destroyed" and "Knocked out" status? Sometimes a penetration causes tank to be "Destroyed" or "Knocked out" - even if it didn't kill anyone or make any visible damage of tank systems. I understand this as tank as a whole being non-operative, but what's the difference between the two ?

Your own tanks report as "destroyed" and enemy tanks report as "knocked out". I believe this is connected to fog of war.

Hmm - I wonder, how the crew of the firing AI tank knows, the tank has "destroyed" status so they don't waste more rounds on it ? The tank that doesn't burn, the crew is inside, but somehow the enemy knows it's "destroyed" and not fire on it anymore . IIRC in CMx1 crews were firing as long, as the enemy tank either was set on fire or the enemy crew was seen evacuating. Seems in CMBN they stop firing when they "destroy" or "knock-out" the enemy tank... How do they know ? .

This is not correct. AI will sometimes take one or two additional shots at knocked out tanks that haven't burned/exploded.

But the effects of penetrations (especially APHE ones !!!) on crew morale are undermodelled. They should more easily panic and try to evacuate, or become shocked and non-responding. Currently even penetrations that killed some crewmembers, don't have much influence on the remaining crew. There is also no (visible) modeling of lighter wounds and temporary incapacitating of crewmembers - in cases they didn't die, but were lightly injured or stunned by shrapnels or burster detonation. And it's hard to imagine for me than an 40-50g HE burster going off inside a tank, could not stun oreveryone for a while, injure, not make thinking about getting out from this smoke filled steel coffin. Not necessarily the burster would kill everyone, but psychological effect should be serious IMHO.

Generally I have to agree. I think crews should be more likely to bail after a penetration, and that penetrations should cause instant disruption and temporary suspension to the crews actions if they don't bail or retreat (or during the short delay before they bail or retreat), especially gunners aiming and firing.

What was VERY different between shorter and longer guns, was of course the kinetic energy - pre and especially post penetration . There is no question about this. But on every effective penetration, where the shell remained intact and fuse was not broken in the process, the HE burster should go off causing some nasty effects on the crew. Additional high kinetic energy could only make it worse.

This is what Steve means. You have to look at energy in addition to caliber. A "75mm penetration" has a wide range of potential terminal effects.