Definition of a Partial Penetration in CM

[shift8]

shift8,

 

The issues raised have been extensively looked into: from firing trials by both the Germans and the Russians, penetration calculations and combat experience. You can learn a great deal from reading the thread, which gets into the arcana of test targets, test target composition and hardness, penetration criteria, armor quality and much more. Back when JasonC was holding forth in fine fashion, I'm pretty sure he didn't have the advantage of the grog fest that is Archive Awareness. Here, for example, is a post which shows original Russian penetration test data for a whole series of guns. The comments after the post go into considerable detail not discussed in the post proper. Russian firing trials: T-34's F-34 gun vs every German tank type from Czech 38-T through Panzer IV. Full details available from Peter Samsonov, whose site it is.

 

Let's do some spot comparisons, shall we? T-34 M41 (cast turret) (F-34 gun, L/42) vs Panzer IV/E (inferred based on other tanks tested, we're talking a Barbarossa period version, but with 20 mm add-on side plate, thus "E" model). From the CMBB Strategy Guide, page 2/31, the penetration numbers in mm are as follows:

 

100   meters (69)

500   meters (71) Delta may be shatter gap related, since Germans are using face hardened armor.

1000 meters (62)

 

Panzer IV/E, ibid. , page 2-47, Upper Hull is 30 + 30, giving an apparent 60 mm protection. I say apparent because there are other factors at work here, depending on what's fired, where and how it hits, etc. Spaced armor isn't the same as monobloc armor. Even so, it's apparent the T-34's gun marginally penetrates the Panzer IV/E's frontal Upper Hull at 1000 meters. This fits the Russian test results in which at 800 meters (max range tested) the AP shell goes smashing through.

 

(Fair Use)

 

The PzIV is tested next. Its front armour is penetrated at 500 meters (entrance diameter 90 mm, exit diameter 100 mm). From 800 meters, another penetration. The front armour plate is shattered into two pieces. Another shot from 800 meters penetrates the front. The testers switch to firing at the side at 800 meters.

 

Now, let's look at the Sturmgeschutz III/F, with its 50 + 30 Upper Hull. A straightforward comparison of that armor with the F-34's CMBB penetration figures indicates getting through the armor is hopeless--at any range from zero out. Really?

 

The German test data shows the F-34 can defeat the StuG's thick frontal armor as follows:

76.2mm. L.42.5 F-34.

APHE (propellant black powder with nitro-celuose primer).

81mm. at 100 metres.

69mm. at 500 metres.

61mm. at 1,000 metres.

HVAP "Arrowhead" (propellant nitro acetone based).

104mm. at 100 metres.

94mm. at 500 metres.

85mm. at 1,000 metres.

 

The same F-34 gun can defeat a dead-on Tiger 1's frontal armor at 100 meters. This being the case, how is it, then, that a Tiger 1's Upper Hull (110 mm @ 9 deg slope--calculator used below gave erroneous results on effective thickness) can be defeated by the F-34, presumably firing AP shell, at 100 meters based on Russian firing tests conducted after Kursk, else Ferdinand wouldn't be in list, but in CMBB, 80 mm of armor on the StuG III/F can't be defeated at zero range? What's wrong with this picture?

 

The above is but one example of why there are long threads talking about the undermodeling of Russian guns. In game terms, the StuG III/F is a super AFV vs the T-34/76s (immune vs it frontally at all ranges), but it can kill the T-34/76 M41 (effective Upper Hull armor is 52 mm--45 mm @ 60 deg) out to 2000 meters.

 

KwK L/43 penetration

 

100   meters (128)

500   meters (117)

1000 meters (104)

2000 meters (82)

 

Still think CMBB is right in how it models Russian gun performance vs German AFVs?

 

Regards,

 

John Kettler

 

For starters, I dont know what version of CMBB you have....but those penetration values arent whats given in game.

 

The T-34 has the following values for the 76: 

APC from 100, 500, 1000m: 93, 73, 63. 

 

APCR: 133, 95, 62. 

 

Actual Russian numbers for the APC round: 88, 69, 60. (http://amizaur.prv.pl/www.wargamer.org/GvA/weapons/soviet_guns5.html)

 

APCR: 500m 90mm, 1000m 60mm. 

 

With APCR, it would certainly make it though at 500m or so-----and it does just that in game. So I dont know what the deal is. 

 

76mm APC did not penetrate the 80mm of armor on Stugs or Pz4s: in game, theoretically, or IRL. It doesnt even come close. Even the German figure you posted completely agree with that. 

 

Also, you info on the Tiger is wrong. The Front Upper Hull, by which I think you mean superstructure: is 100mm thick, 100.9mm if you want to nitpick and add in the slope. 

 

To Boot, the chart you lined to shows a maximum penetration at 100m of just over 90mm. Basically in agreement with what I just posted. Totally in inadequate to make it thought the Tigers Hull. 

 

CMBB and RT do the armor just fine. The Both the chart you sent, the games values, and the data I posted all agree that the 80mm is too much for the 76mm in T-34 except at 100m or less. 

Edited June 22, 2015 by shift8

[John Kettler]

shift8,

 

I have CMBB, but I can't play it, since I no longer have a Motorola chip in my iMac. I took the data from the CMBB Strategy Guide, the CMBB bible, if you will. Perhaps a patch subsequently changed the F-34 penetration numbers. I don't recall where I got the Tiger 1 UH figure, but it's possible I conflated it or that a typing problem I sometimes have (fingers don't listen to brain) may've caused the mistake. You seem to flatly contradict yourself when it comes to F-34 penetration performance.

 

CMBB numbers for 100, 500 and 100 meters APC 93, 73, 63 APCR 133, 96, 62

 

You then cite actual Russian figures of 88, 69 and 60 for APC, which are pretty close to the CMBB numbers. Either set of APC values will pierce the 80 mm on the StuG III/F's UH. Next, you say

"76mm APC did not penetrate the 80mm of armor on Stugs or Pz4s: in game, theoretically, or IRL. It doesnt even come close. Even the German figure you posted completely agree with that."

 

Is this some sort of New Math? If we use the German numbers for APC, the F-34 can barely penetrate (by 1 mm) the armor at 100 meters, but using the CMBB numbers you provided, absolutely will penetrate it at 100 meters (93 > 80). In reviewing the penetration curve chart I linked to, I see my brain got a bit overloaded from too much going on visually, causing me to read the wrong line. The Russian original is much easier to follow, since each curve is directly labeled. I should've said Russian data show the F-34 will defeat the Tiger 1's 80 mm thick side armor at 100 meters. Obviously, this means the projectile is APC. If the F-34 can defeat the 80 mm thick vertical UH side armor on a Tiger 1 at 100 meters, how is it, then, it can't defeat the self same 80 mm on the UH front of the StuG III/F as you directly state? Also, I'd be willing to bet the armor quality on the Tiger 1 is better than what that StuG has. 

 

Regards,

 

John Kettler

Edited June 22, 2015 by John Kettler

[shift8]

shift8,

 

I have CMBB, but I can't play it, since I no longer have a Motorola chip in my iMac. I took the data from the CMBB Strategy Guide, the CMBB bible, if you will. Perhaps a patch subsequently changed the F-34 penetration numbers. I don't recall where I got the Tiger 1 UH figure, but it's possible I conflated it or that a typing problem I sometimes have (fingers don't listen to brain) may've caused the mistake. You seem to flatly contradict yourself when it comes to F-34 penetration performance.

 

CMBB numbers for 100, 500 and 100 meters APC 93, 73, 63 APCR 133, 96, 62

 

You then cite actual Russian figures of 88, 69 and 60 for APC, which are pretty close to the CMBB numbers. Either set of APC values will pierce the 80 mm on the StuG III/F's UH. Next, you say

"76mm APC did not penetrate the 80mm of armor on Stugs or Pz4s: in game, theoretically, or IRL. It doesnt even come close. Even the German figure you posted completely agree with that."

 

Is this some sort of New Math? If we use the German numbers for APC, the F-34 can barely penetrate (by 1 mm) the armor at 100 meters, but using the CMBB numbers you provided, absolutely will penetrate it at 100 meters (93 > 80). In reviewing the penetration curve chart I linked to, I see my brain got a bit overloaded from too much going on visually, causing me to read the wrong line. The Russian original is much easier to follow, since each curve is directly labeled. I should've said Russian data show the F-34 will defeat the Tiger 1's 80 mm thick side armor at 100 meters. Obviously, this means the projectile is APC. If the F-34 can defeat the 80 mm thick vertical UH side armor on a Tiger 1 at 100 meters, how is it, then, it can't defeat the self same 80 mm on the UH front of the StuG III/F as you directly state? Also, I'd be willing to bet the armor quality on the Tiger 1 is better than what that StuG has. 

 

Regards,

 

John Kettler

Sorry my bad, I should have been more clear, 

 

I mean at 500m or more, not that it couldn't penetrate at any range. Ive seen the F-34 kill Pz4 from SH and LH in game from 200m or so. Ive seen flukes farther than that, but reliably. 

 

Sorry for that confusion, I thought the debate was for 500m distance, not any range. Of course F-34 could do it at 100, or even 200m. MAYBE even 500m, but not reliably I think. 

[John Kettler]

shift8,

 

Appreciate the clarification.

 

Regards,

 

John Kettler

[BLSTK]

@ GeorgeMC

 

Still waiting for those pix...

[LukeFF]

@ GeorgeMC

 

Still waiting for those pix...

 

Grow up, and quit being a troll.

[Bulletpoint]

Grow up, and quit being a troll.

 

I guess trolls never grow up, they just get bigger

[Sublime]

Sorry, the location of crewmembers and fuel tanks is not taken into account.

I once guessed at how the game models damage, and much to my surprise Steve actually confirmed I was basically correct (darned if I can find the post now though...).

It works in this way:

1: Shot energy checked against armour thickness and angle at point of impact. Extra modifiers might be given for type of munition. In this way, hollow-charge weapons can penetrate despite their low velocity.

2: If there is enough energy to penetrate, the combined armour value is subtracted from the shot energy.

3: A "dice roll" is made on a lookup table, with a modifier for the amount of energy that penetrated the armour. Possibly with a bonus for AP-shells that have an explosive charge. This gives the total "damage value"

4: Depending on the damage value, the tank suffers damage to random components and crewmembers, with high values more likely to make the tank blow up.

It might be that there are different look-up tables for the main parts of the tank, and maybe there's a separate table for crew damage and component damage. That would mean that shots that almost penetrated but were deflected still had the chance to cause spalling, but that spalling then only gives a roll on the crew damage table. This is conjecture on my part.

If I'm correct, then this means "partial penetration" might be like spalling, a hit that barely made it through the armour, but which has a chance to roll on both component and crew damage tables, albeit with a low damage value.

thats not true. first of all i find it very cynical to imply bfc added partial penetration to the coding to have no effect but make the game seem more realistic.

second your completely wrong about crew members and fuel tanks location not being taken into account. they are. in favt every device that can be damaged is located where it should be and can be damaged. there is the now famous anecdote of bfc not being able to figure out why Tigers couldnt spot correctly until they realized they had the crew member (cmander iirc) facing backwards in the tank. once facing forwards the problem was solved.

finding a post where steve said you were right shouldnt be hard AT ALL. just search for post with your name. search those for the word steve. steve usually signs his name thus

Edited June 23, 2015 by Sublime

[BLSTK]

Grow up, and quit being a troll.

 

I sooo want to be like you when I do grow up.

 

In the meantime, try getting a life.

 

(P)resident Troll™

Edited June 23, 2015 by BLSTK

[Thewood1]

Do you two knuckleheads mind taking this outside.

[Mord]

Sorry, the location of crewmembers and fuel tanks is not taken into account.

 

4: Depending on the damage value, the tank suffers damage to random components and crewmembers, with high values more likely to make the tank blow up.

 

It might be that there are different look-up tables for the main parts of the tank, and maybe there's a separate table for crew damage and component damage. That would mean that shots that almost penetrated but were deflected still had the chance to cause spalling, but that spalling then only gives a roll on the crew damage table. This is conjecture on my part.

 

 

 

 

I thought Jon already clarified that hits do take into account where crew members are sitting. Which makes sense because Steve described a bug early in CMBN's development where the spotting in a buttoned Tiger turret was off because the TC was facing the back of the tank instead of forward. So, apparently the engine knows right where the crew is for spotting purposes so why not for penetration/damage?

 

 

Mord.

[sburke]

Only conjecture - it would I suspect depend on what is behind this in the vehicle model. So if a crewmember is behind that armor at that spot you can expect them to be killed. If it's a fuel tank then it could be the fuel goes up and the vehicle catches fire.

 

So you'd have to know how the vehicles are modelled in game terms and how the game engine handles the data for differing type of hits. Assuming of course it does.

 

This could account for why some players see a tank being hit - partial penetration and the tank continues to operate whilst other tanks (depending on where hit) showing a partial penetration may be KO'd or have the crew bail due to losing crew members/damage to systems.

 

See where I'm going? i think there are a great many variables - from penetration/armour harness/angles; vehicle damage models; crew member 'soft' factors e.g. morale etc potentially at play that any of which may affect the outcome. So it may be difficult to provide a black and white answer?

I think that is more the issue.  Whether is it a partial or full penetration isn't the core issue.  It is where it hit and what is effect.  The variables are huge here.  A partial penetration at one point may be worse than a full penetration at another and either may not matter if the crew is already in a state where they might bail.  I suspect you are exactly correct.  There is no straightforward black and white answer as to result.

[Bulletpoint]

your completely wrong about crew members and fuel tanks location not being taken into account. they are. in favt every device that can be damaged is located where it should be and can be damaged. there is the now famous anecdote of bfc not being able to figure out why Tigers couldnt spot correctly until they realized they had the crew member (cmander iirc) facing backwards in the tank. once facing forwards the problem was solved.

finding a post where steve said you were right shouldnt be hard AT ALL. just search for post with your name. search those for the word steve. steve usually signs his name thus

 

Managed to find the post I was talking about:

 

http://community.battlefront.com/topic/112811-ever-seen-a-machinegun-blow-up-a-tank-well-now-you-can/?p=1497585

 

 

Posted 07 March 2014 - 09:26 PM

 

 

Yes, there is no special tracking of the round's path on the inside of a vehicle that is totally contained within the vehicle (i.e. not a pass through).

acrashb said

Residual energy is taken into account, correct.

Steve 

 

Edited June 24, 2015 by Bulletpoint

[Sublime]

but where it initially strikes is taken into account. if not how else do you account for patch notes like blowout ammo bustle sinulated for T90AM so should be less explosions. amd also that dame quote means through and through penetrations are modelled

[BLSTK]

Do you two knuckleheads mind taking this outside.

 

I'd love to. It appears, however, as if Luke has flown the coop.

[Sublime]

partial penetration = 'just the tip'

=p

[Battlefront.com]

but where it initially strikes is taken into account. if not how else do you account for patch notes like blowout ammo bustle sinulated for T90AM so should be less explosions. amd also that dame quote means through and through penetrations are modelled

This is correct. Bulletpoint misinterpreted what I wrote in that earlier post. It seems he thinks that once there is a penetration that there is a dice role to determine what gets damaged and what doesn't. That is incorrect. The location, type, and severity of the penetration all matter. Which should be pretty obvious because a partial penetration to the rear engine of a tank doesn't cause a driver casualty

There is no "damage table" either. There is, in fact, no tables of any sort. That's how other games handle things (if even that), but CM is physics based not table based. Which is to say your interpretation on the previous page of this thread is not what happens in the game. At all.

What my earlier post referred to is that there is no explicit ricochet or specific splintering/spalling simulation inside the vehicle. There is no attempt to figure if the 20mm shell bounced off the breech and hit the gunner in the leg or that there were 256 pieces of spalling of various sizes and then trace where each one landed. Instead the area partially penetrated is examined and the effect calculated, then applied with random variability to the systems that could possibly be affected by the penetration.

Hopefully that clarifies things.

Steve

[Battlefront.com]

I sooo want to be like you when I do grow up.

 

In the meantime, try getting a life.

 

(P)resident Troll™

You're going to be President Banned if you keep that up. KNOCK IT OFF.

Steve

[BLSTK]

FWIW, he did provoke me.

 

I certainly hope LukeFF gets the same warning.

 

I would hate to think there might be a double standard when it comes to "internal discipline".

Edited June 24, 2015 by BLSTK

[Battlefront.com]

As far as I can tell you started digging on George and Luke, as well as others, confronted you. You also have made sure it continued. So you earned your warning, nobody else did. Do not try to play the martyr because the record is here for the public to look at.

Steve

[BLSTK]

And while George no doubt saw the humour, Luke couldn't spell the word.

 

As tempting as it must be to play god, perhaps we should let the public be the judge. I stand by my comments.

[Bulletpoint]

This is correct. Bulletpoint misinterpreted what I wrote in that earlier post. It seems he thinks that once there is a penetration that there is a dice role to determine what gets damaged and what doesn't. That is incorrect. The location, type, and severity of the penetration all matter. Which should be pretty obvious because a partial penetration to the rear engine of a tank doesn't cause a driver casualty

There is no "damage table" either. There is, in fact, no tables of any sort. That's how other games handle things (if even that), but CM is physics based not table based. Which is to say your interpretation on the previous page of this thread is not what happens in the game. At all.

What my earlier post referred to is that there is no explicit ricochet or specific splintering/spalling simulation inside the vehicle. There is no attempt to figure if the 20mm shell bounced off the breech and hit the gunner in the leg or that there were 256 pieces of spalling of various sizes and then trace where each one landed. Instead the area partially penetrated is examined and the effect calculated, then applied with random variability to the systems that could possibly be affected by the penetration.

Hopefully that clarifies things.

Steve

 

I stand corrected then. Thanks for clarifying.

[LukeFF]

And while George no doubt saw the humour, Luke couldn't spell the word.

 

As tempting as it must be to play god, perhaps we should let the public be the judge. I stand by my comments.

 

My humor meter is calibrated just fine, thank you. It was you who decided to interject low-brow, juvenile comments into this topic, so that's why I called you out on it. I'm not the fool you apparently think I am.

[BLSTK]

You said it. "Fool". Your words not mine. What I think of you can't be printed in this Forum.

 

And just because you don't get the joke doesn't give you the right to call someone a "troll". You are the one stooping to name-calling. I call it hypocrisy. And you are a hypocrite. You can look that one up too while you're at it.

 

So before you start telling someone else to "grow up" you might want to ask yourself the following question: did you even finish school or did school finish you?

[Quintus Sertorius]

That picture of the 17-pounder shell poking through the armor plate makes me wonder how hot the metal would be immediately after the impact.  Hot enough to be glowing, I would think.