Damage to AFV's by 20mm/37mm - possible inaccuracies

[Specterx]

One thing that often bugs me about CM is that a shell, even light ones (20mm, 37mm) almost always "knocks out" a vehicle when it penetrates. Now, a tank shouldn't become knocked out unless it has suffered some kind of catastrophic damage - fuel exploding, gun destroyed etc., and a 20mm round sure isn't going to cause that kind of damage in one hit. I remember reading somewhere that until tank guns got up to about 75mm in size a tank would often have to be hit with five rounds or more before it would become combat-useless (either by crew casualties or internal damage).

A related problem that I have concerns mostly open vehicles, like the M7 Priest. If an AP shell were to hit the Priest, wouldn't it be more likely to simply pass through the armor than cause real damage?

Does anyone have any real data on this?

[Ellros]

I don't know about you, but if a 20mm shell passed thru a vision slit and bounced around,. I sure would not want to be a crewman in that tank. That's part of how the small shells knock out the larger tanks... by causing crew casualties and damaging interior equipment.

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Ellros:

I sure would not want to be a crewman in that tank. That's part of how the small shells knock out the larger tanks... by causing crew casualties and damaging interior equipment.<HR></BLOCKQUOTE>

This was my first thought as well. But upon reflection, some pictures I've come across, and some things I've seen, I think he may have a point.

It would seem that in game terms a penetration is a penetration -- it doesn't matter where or how. And once penetrated, I don't think the size of the penetrator is factored into the damage it does (I, of course, stand to be corrected on that point by the BTS powers that be).

So, theoretically, a lighter, smaller projectile should be less likely, though not necessarily unlikely, to score a one-penetration kill against even heavy AFVs. It's worth an examination anyway.

[ 04-25-2001: Message edited by: Babra ]

[Michael Emrys]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Babra:

So, a lighter, smaller projectile is going to be less likely, though not necessarily unlikely, to score a one-penetration kill against even heavy AFVs. It's worth an examination anyway.<HR></BLOCKQUOTE>

Basically I agree with you. All things (like velocity at point of impact) being equal, a larger round is going to both be more likely to penetrate and do more damage once inside.

But just to keep the controversy going ( ), I want to repeat that even a small round has some chance of causing casualties, fires, and catastrophic explosions. If a small round penetrates a

[Mr. Johnson--]

For some really run action, grab a bunch of 50mm ATGs in the custom scenario. Fill each one with all Tungsten and stick a ton of tanks in front of them. You get lots of non damaging penetrations.

20/37mms usually can't even kill medium or heavy tanks at all. And the 37mm ATG was the primary tank killing gun for the Germans during the eary years. That thing packs a mean punch. I would not want to be in that stuart that gets punched with one of those.

[Guest Babra]

As I said, less likely, though not necessarily unlikely.

I'm specifically thinking of some pics I've seen of knocked out vehicles with LOTS of small penetrations. It's impossible to say how many of those were done after it was dead, but it makes ya wonder...

[Dunnee]

I would like to see those small shells on occasion damage a tank and injure crewman, because there have been tanks that took hits and kept on fighting. Maybe show them with battle damage(could this be done? I don't know. . ) like smoke and flames, maybe some holes, or you can only make left turns. Something about a panther thats smoking from six holes and leaking oil. . .but still firing. . .i like it.

[Tiger]

In a game against the computer I had a lynx that was at full speed heading for cover get nailed in the turrent by a British Sherman III 75mm. Side Turrent penetration, no serious damage! Not even a crew casualty. Talk about lucky.

-Tiger

[André]

Remember that 20mm and 37mm German guns fire bursts. If a series of bursts penetrate the armour of a lightly armoured vehicle you would probably have a lot of shrapnel flying around inside the vehicle. So Specterx, a burst of 20mm or 37mm fire can be very deadly indeed. Possibly more deadly than a single shot from a 50mm PAK.

Heinz

[aka_tom_w]

Penetration without result (no damage) is modeled. Its fluky but it does sometimes happen that a round will penetrate an AFV and there will be no damage (VERY lucky). I would say the size or diameter of the round is not taken into account in this penetration result. BUT when a burst of German 20 mm or 37 mm hit and penetrate an AFV I have never seen a penetration without result due to the "burst" nature of these weapons.

-tom w

[ 04-25-2001: Message edited by: aka_tom_w ]

[Olle Petersson]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Specterx:

One thing that often bugs me about CM is that a shell, ... almost always "knocks out" a vehicle when it penetrates.

Now, a tank shouldn't become knocked out unless it has suffered some kind of catastrophic damage - ...<HR></BLOCKQUOTE>I think this is a matter of definition.

The kind of damage you refer to is what makes a vehicle "Destroyed" in CM.

"Knocked out" is what you have when it's combat ineffective, but can return to combat after reparation.

The third alternative in CM is "Abandoned", that happen when the crew leave a funcional (but usually immobile) vehicle.

Cheers

Olle

[CombinedArms]

Just mentioning this because I'm not sure I've seen it mentioned: "Penetrations" of AFVs that result in "no damage" are fairly common in the game, esp with smaller rounds. At least, I've seen them happen a lot both to my vehicles and the enemy's. Also gun hits that result in no damage (you can tell if the gun keeps firing.)Sometimes when a main gun is damaged you also lose the MGs, but sometimes not.

I've never seen a penetrating 75mm round not kill a concrete pillbox, but 37 mm rounds often penetrate w/o killing.

So from what I can tell, all of this IS modelled in the game. Also 20mm rounds generally just bounce off a Sherman--maybe very rarely one penetrates, but I think the operant word is RARELY.

[abuhabib]

my panzer vi (tiger), with its 88 canon, at close range (about 60 meters), penetrated a stuart without (!) a knockout. food 4 thot, eh? needless to say, it was cooked well n good by the next hit.

[Username]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Michael emrys:

. In a newsgroup I frequent, someone raised the question the other day as to which constitutes the greater fire hazard, gasoline or diesel. Another person answered that diesel was a greater hazard, and his reasoning interested me. He reminded us that all engines leak fuel. But whereas gasoline will evaporate quickly, diesel will pool and remain as a fire hazard. Now I know that someone is now itching to point out that the fumes of gasoline are the greatest hazard, and that is true. But it occurs to me that in a properly ventilated engine compartment, fumes are not going to accumulate. I'm not exactly sure just what my position on this matter is. My mind is open...not to say vacant.

<HR></BLOCKQUOTE>

You can put a cigarette out in a bucket of diesel. Anyone that smokes near any gasoline that isnt capped off is a total fool.

If what you say is true (not really but) then sloshing fuel hitting white hot exhaust manifolds can flash over (problem with panthers). Gasoline engines , in WWII, used carbs almost exclusively. Diesel, as far as I know, must be injected. So pooling diesel is from a pressurized leak that would make a terrible pool and /or mist of fuel. Not likely. Perhaps your newsgroup guy is saying that all fuel tanks leak (you can pressure test tanks) but thats what I think.

But to get back to the issue, Its ammo that is the greatest immediate fire danger for tank crews. Its highly flammable and in the same compartment as them. A fuel fire is usually in another space and the crew can bail with singed hineys.

So most any shot that gets inside can tear open a shell casing. Its steel on brass and theres sparks. A torched off 75mm shell case has enough powder to chase out a crew in tens of milliseconds.

Lewis

[rexford]

The Australians estimated that one penetration of a PzKpfw II by 2 pounder AP was sufficient for a "kill", but two were required against PzKpfw III and IV.

Energy left after penetration is another issue. If a 37mm Stuart round with 70mm penetration gets thru 80mm on Tiger side, the residual energy in the tank is going to be close to zero (comparing penetration data to armor, how does Stuart 37mm penetrate Tiger and Tiger II side armor?).

Russians in Spanish Civil War fought in tanks with soft armor, if penetrations didn't hit anyone they often would do little or nothing (37mm and 20mm).

One penetration of M13/40 was usually enough, armor would give off big high velocity chunks. Crews reported to survive few penetrations.

KV-II tank that held up Germans during 1941 was penetrated several times by 88 and turret crew was still in there ready to fire.

The issue with small AP is like someone firing a pistol at a car with a few people in it. Some shots won't do much, others will do it all. Solid shot, like 37mm fired by Stuarts and 2 pounder from English vehicles, has more penetration than rounds with HE filler but does a little less inside if the added velocity is neutralized by thick armor.

[Head Mahone]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Heinz 25th PzReg:

Remember that 20mm and 37mm German guns fire bursts.

Heinz<HR></BLOCKQUOTE>

Heinz is correct Specterx. It is the burst of multiple rounds penetrating multiple times that is causing the kill. Now we move on to the 37mm getting a single kill with a single shot. I've been hit with small calibers such as these and have received "Penetration No Serious Damage" or crew casualties resulting from it many times. To that I'd say the game is modeled fine in this aspect.

-Head

[Warmaker]

Keep in mind this also: not only do you consider the damage of an AP round itself on penetration against crew/equipment you also have to remember the metal fragments from the armor itself from the penetration will be flying around. To die in a burning tank also has to be one of the worst ways to die IMO.

[Dunnee]

I realize that in CM u can have penetrations with no damage, but I want to see battle damage on the tanks if they survive some hits. I know it probably can't be done, but I wonder. . .

[Stalins Organ]

IIRC a number of British Matilda 2 tanks weer "KO'ed" during the battle of Arras in 1940 by having storage bins on the outside set on fire by 20mm flak hits.

Penetrations are not the only way of knocking out a tank......except in CM!!

[AFLC]

Ok...and now for my first post...

I remember seeing a JagPanther on display at the Imperial War Museum. It had been hit 4 or 5 times (penetrated) on the hull in the engine compartment. Those were full penetrations. I took a pic of those with friend of mine sticking his hands into the holes. And I don't believe this was a extraordinary event. I makes sense that if the crew compartment isn't hit directly or if the tanks doesn't explode (even if catches fire, there was fire fighting equipment)it might be imobilized but still keep on fighting. This must have been the case, or else, the tank that destroyed wouldn't keep on shooting at it.

[Fuse]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Username:

You can put a cigarette out in a bucket of diesel. Anyone that smokes near any gasoline that isnt capped off is a total fool.

If what you say is true (not really but) then sloshing fuel hitting white hot exhaust manifolds can flash over (problem with panthers). Gasoline engines , in WWII, used carbs almost exclusively. Diesel, as far as I know, must be injected. So pooling diesel is from a pressurized leak that would make a terrible pool and /or mist of fuel. Not likely. Perhaps your newsgroup guy is saying that all fuel tanks leak (you can pressure test tanks) but thats what I think.

Lewis<HR></BLOCKQUOTE>

Along these lines, my father's a mechanic for a shipping company and I remember him telling me that it is possible to weld a fuel tank that still has diesel in it. Doing the same for a tank with gasoline would be VERY George W'ish.

[Stalins Organ]

AFLC - I think I've seen the same Jagdpanther when it was at Duxford 20 yrs ago. IIRC the commentary said it had been knocked out by rockets.

There are a number of ways that you might get several hits - as you say, the original "killers" might not eralise they had ko'ed it and kept pumping rounds into it. Or maybe a day later a new crew came along, saw it and pumped a few more in, or mybe 2-3 of the typhoon's rockets hit from teh saem salvo, or maybe another typhoon saw it a bit later and put another round in and claimed the kill to?!

I think the detailed hit info should be able to be turned off for an entire game, and the status of AFV's should be only indicated by their picture (ie no bases showing if they're still active or not) - that would encourage players to keep on shooting until they blew up/caught fire, as seemed to be historical practice!

[Mr. Johnson--]

Good call Mike the Bike. That would be good, something to encourage players to keep shooting until the tank burned.

[Lars]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Username:

You can put a cigarette out in a bucket of diesel. Anyone that smokes near any gasoline that isnt capped off is a total fool.<HR></BLOCKQUOTE>

Actually, you can put a cigarette out in a bucket of gasoline too. It's only the fumes that are explosive

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Fuse:

Along these lines, my father's a mechanic for a shipping company and I remember him telling me that it is possible to weld a fuel tank that still has diesel in it...<HR></BLOCKQUOTE>

I sat in on a Coroner's inquest a couple of years back for a guy who had the same belief, God rest his dumb-ass soul. What he didn't know or realize is WHY.

Fire (and explosions) need three things: Fuel, oxygen, and heat. If the tank is absolutely full, no oxygen, no fire. But heaven help ya if it ain't...