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Christ on a crutch. I said I was done but this is too much.

 

 May I remind you that my input is the only reason you are not still blathering on about shatter gap?

 

 

What I claimed to have proof of is that the game "uses different terminology" than the 1944 report. I did not claim to have proof of what BFC's definition of a PP is. Do try to keep up.

 

 

What?! Where did I say that I did not agree with the Army report? Oh that's right, I didn't. You just made that up.

 

Oh good, your back!

 

 

We aren't talking about shatter gap specifically any more, do try to keep up will you? :D

 

And MY argument was never that the U.S. Army definition was used one for one. The lack of CM DOES make that clear. It does not prove that simply because they lumped CM in with one of the two other words, that the army's definition of a PP, and mine, are not compatible.  What that also DOES NOT prove is that your perspective on how CMBN defines it is true. It is a non-sequitur to argue that just because BFC didn't use CP, and therefore didn't use all the army terms, then we just throw it all out and use your definition of PP, where the word partial has not meaning whatsoever, since you said it was a round that penetrated at a lower energy state as I recall. Therefore you have not proven that Partial penetrations are not what I say they are. And for that matter, I never stated that the BFC did use the Army terms one for one, my intent was to demonstrate how people my might normally define rounds that do not PTP. 

Edited by shift8

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And I keep pressing upon you that you have no reason to think that. BFC hasn't said anything either way.

Perhaps, but if your entire argument depends upon a definition then you don't really have an argument of substance because if your definition isn't the same as BFC's definition the discussion is effectively over.  You aren't bringing anything else to the table.  If the game is massively flawed if we assume that your definition is correct or that the game is just fine if your definition is incorrect I would have to say that the assumption should be that you are the one in error on this topic.  After all, we know that BFC has consulted experts in the field when creating the penetration formulas for the game and until now nobody has found any errors in the game on this topic at least since the CMx2 engine was created.  I believe the formulas were changed for CMx2 because Rexford himself contacted BFC and personally discussed the topic with them IIRC.  If we know that Rexford himself consulted with BFC on this issue I think that it is safe to assume that such a basic error that is implied by this definition 'issue' is something that would not have made it into the game.  At least, unless you think that BFC is completely incompetent. There is nothing wrong with raising an issue and subsequently finding out that you may have made a mistake.  The only thing that remains is whether the person making the mistake decides to keep banging the same drum and making himself look like a fool. 

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Perhaps, but if your entire argument depends upon a definition then you don't really have an argument of substance because if your definition isn't the same as BFC's definition the discussion is effectively over.  You aren't bringing anything else to the table.  If the game is massively flawed if we assume that your definition is correct or that the game is just fine if your definition is incorrect I would have to say that the assumption should be that you are the one in error on this topic.  After all, we know that BFC has consulted experts in the field when creating the penetration formulas for the game and until now nobody has found any errors in the game on this topic at least since the CMx2 engine was created.  I believe the formulas were changed for CMx2 because Rexford himself contacted BFC and personally discussed the topic with them IIRC.  If we know that Rexford himself consulted with BFC on this issue I think that it is safe to assume that such a basic error that is implied by this definition 'issue' is something that would not have made it into the game.  At least, unless you think that BFC is completely incompetent. There is nothing wrong with raising an issue and subsequently finding out that you may have made a mistake.  The only thing that remains is whether the person making the mistake decides to keep banging the same drum and making himself look like a fool. 

Again, Im not saying the entire model is wrong, only the performance of certain guns vs this specific tank. It is entirely possible that they got 99% correct and made a mistake here and there, in fact, it is absolutely Impossible that everything is perfect. Tons of other people on this forum have questioned all sorts of things on the armor model in this game, there decades worth of threads on it. Like I stated, I dont think im being ridiculous to have one single problem with it. I mean for heavens sake, Vanir also thinks there is a problem here, but to him its the LACK of shatter gap that is a problem. 

 

Everyone's argument here, not just mine depends upon what a partial penetration is. No one else is bringing anything to the able either, seeing as we've been arguing the definition alone for about 2 pages. So where is your plea for them to shut up?  And yes, unless we get acknowledgement from BFC saying one way or another, nobody knows. But several peoples ideas on what a partial pen could be are not rational. If BFC made some irrational labels, I'll believe it when they say it. Until then, it is not reasonable to suggest that the labels mean anything beyond exactly what they say. 

 

But since you want to bring up the accuracy of the game, have you even thought about said accuracy in the context of other tanks and guns in this game if you DID count a PP as just a slow P? If you did we'd have alot more problems in this game, things that Rexfords book would certainly be opposed to. Unless of course you think Rexford would argue the M3 gun on the Sherman should be able to perforate a Pz4 80mm lower hull well over 1000m (I see that all the time). And thats only one example, we could be here all day pointing out things like that. How about the Panther mantle for example? There are people here who dont think it should be penetrated beyond 200m, yet if were counting PP's it most certainly does at least out to 500m. 

Edited by shift8

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What that also DOES NOT prove is that your perspective on how CMBN defines it is true. It is a non-sequitur to argue that just because BFC didn't use CP, and therefore didn't use all the army terms, then we just throw it all out and use your definition of PP, where the word partial has not meaning whatsoever, since you said it was a round that penetrated at a lower energy state as I recall. Therefore you have not proven that Partial penetrations are not what I say they are. And for that matter, I never stated that the BFC did use the Army terms one for one, my intent was to demonstrate how people my might normally define rounds that do not PTP.

 

I never claimed to know or have proof of BFCs definition of partial penetration. In fact I said the opposite.

 

I don't know for sure what the difference is between a "Penetration" and a "Partial Penetration" in CM, but my impression from years of observing after armor effects in CM is that they are essentially the same thing except that one has more residual energy than the other. PPs in-game are definitely penetrations into the interior, not bulges or cracks; those fall under the Spalling category. PPs destroy tanks, spalling does not, therefore in game terms the dividing line between success and failure lies there.

I do think that PPs in Combat Mission are meant to represent some type of penetration into the interior, and I believe that is supported by the observed after-armor effect (and I also think your claim that 30% of non-penetrating hits should be expected to knock out the tank is crazy and completely unsupportable).

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Rinaldi claimed that not me. And that figure was vs the Tiger. what percentage of PP's that killed a tank would be entirely subjective to just how close that gun was to penetrating. So if you have a guns that just a few MM from doing the job, it stands to reason that alot of failed hits have a high chance of displacing plate into the tank. 

 

 

As to the first part, I derived that you were implying proof by referencing the original argument from before, when you first quoted me on the matter. 

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Rinaldi claimed that not me.

According to what Rinaldi stated, which is line with my own experience, PP only kills about 30% of the time. Which is what I would expect from a round that doesn't make it through the armor, but depending on how far it got, might send huge chunks of the armor through the tank.

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I am done arguing definitions. Yes, the game uses different terminology than the 1940s-era US Army. No, that is not "insane" nor does it mean there must be something wrong with the ballistics modeling.

Here you stated that the game DOES NOT, use the same terminology as the the Army. The specific term we were arguing over was the definition of PP, which is clear from part 3 of the post you made before the one Im quoting here. 

 

Hence my not understanding why you seemingly argued that you have proof that the game does not use the same definitions. Clearly CP was placed inside PP or P, but there isnt any proof that the first part of the definition of PP doesn't still hold with the Army's view. 

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Here you stated that the game DOES NOT, use the same terminology as the the Army. The specific term we were arguing over was the definition of PP, which is clear from part 3 of the post you made before the one Im quoting here. 

 

Hence my not understanding why you seemingly argued that you have proof that the game does not use the same definitions. Clearly CP was placed inside PP or P, but there isnt any proof that the first part of the definition of PP doesn't still hold with the Army's view. 

For that specific gun vs armor scenario at that range, yes. It makes perfect sense that a gun that should be penetrating, or is very close to penetrating might inflict serious damage from a near pen. 3 out of 10 hits is not alot. 

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and I also think your claim that 30% of non-penetrating hits should be expected to knock out the tank is crazy and completely unsupportable

 

Sigh. This has clearly gotten lost in the thread, let me quote myself:

 

 

 

 Its all well and good to say you are only counting 'clean penetrations' but when everyone is observing that 'settling for less' in the form of a partial-penetration still yields the desired results (in at least 30 percent of my tests of a 400 sample size - catastrophic kills),

 

I never said bounced, nor did Shift say anything that I said - in fact that's the entire crux of this argument. Everyone should probably take the frequency of posts down a notch and read more carefully what one another are saying. 

FWIW the 'partial penetrations' that resulted in the Tiger having an immediate secondary struck in the following area:

 

16553854567947698176_2015_07_25_00001.pn
 
My point should've immediate obvious to both of you. That, as far as the game is concerned, partial pens can be debilitating and destructive, even immediately so. It was just a little (barely relevant) tidbit from me that said I was more than satisfied with how the penetration system was acting after strenuous testing. 
 
EDIT: In short Vanir I fully agreed with you that partial pens should be counted as hits - largely because they were capable of producing impressive results on one-off hits. Nevermind the fact they often degrade the combat capabilities of the enemy tank.
Edited by Rinaldi

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LOL! Yeah, there's a lot of information being presented and a lot of talking past one another. I think. ;)

 

At this point, I'd love to see a summary. The problem with any question about penetration values is, IMO, that there are so many variables and that most of the discussion is based on theoretical numbers, not tests. (Shoeburyness and Isigny nothwithstanding. Those provided some data, but were hardly thorough enough to create absolute certainty about the ballistics. The purpose of those tests were to see what Allied weapons worked, and which didn't.)

 

An additional complication is that the question here (which I -think- is whether the 76mm should always defeat the Tiger I frontal armor at less than 800m, given a normal angle to the face of the tank), starts to get into the realm of "maybe". (Hold yer horses! Let me esplain.) By "maybe", I mean that neither the armor nor the projectile have an overwhelming superiority over one another. There is no question that a rifle round cannot penetrate a Tiger face. There is no question that a 76mm at 500m will penetrate a halftrack. 

 

I've attached two quickly found internet tables.

 

76mm%20gun%20table.jpg

 

and 

 

76mm%20gun%20table%202.jpg

 

The 76mm gets close to, or exceeds, the 100mm Tiger armor thickness.

 

But wait.

 

What type of armor are the tables based upon? Do they have the same characteristics as the Tiger armor? What is the RHAe of the high-hardness Tiger plate? (They kept that quality up, unlike other tanks.) The Tiger armor's 100mm was a MINIMUM thickness. Often it was a few mm thicker. What about the zimmerit coating? Did that add resistance? Or reduce it? What about hitting things on the front, like brackets, cables, etc? (Then, we can talk about edge effects, too.)

Finally, we also need to realize that the front hull plate was sloped back at 10 degrees from the vertical. 

 

We're splitting hairs. Really.

 

If there is an issue, it needs to be presented clearly. Definitions matter. (Not trying to reignite a flame, just stating a fact.)

 

I think we all recognize that CM's armor/penetration model is probably the best one available to the public. If there is an inaccuracy, I'm sure we all would appreciate it being resolved.

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Vanir Ausf B,

 

The issue of comparing the Russian 85 mm and the US 76 mm was gone into by Rexford in this thread. For APCR, the data show the 76 mm dramatically outperforms the 85 mm at all ranges. When comparing APCBC numbers, the 85 mm slightly edges the 76 mm out to 500 meters, after which the process reverses by a whole millimeter at 1000 meters and 6 mm at 1500 meter range.  From Rexford's #4 here.

http://community.battlefront.com/topic/41573-comparison-of-russian-85mm-hvap-with-american-76mm-hvap/
 

"The U.S. 76mm APCBC round was compared to the 85mm APBC during a Russian firing trial against a captured Tiger II, and the U.S. gun was significantly better at penetrating the Tiger II."
 
(Note: I saw the information he refers to myself before the site suffered a disastrous server crash which wiped out much of the English content. Part of that was a description of head to head penetration tests in which the Russians were blown away that the only gun which got a through and through of the King Tiger turret was the US 76 mm, presumably firing APCR. This was both a shock to them and a shock to me when I read it, for it was so utterly counterintuitive.)

"The report is published on the Russian Battlefield site.

Comparing Russian 85mm HVAP to 85mm APBC against vertical targets results in:

100m: 165mm for HVAP, 139mm for APBC
500m: 137mm for HVAP, 123mm for APBC
1000m: 107mm for HVAP, 105mm for APBC
1500m: 81mm for HVAP, 91mm for APBC

Inside 500m, 85mm HVAP has a higher probability to defeat the Tiger mantlet than 85mm APBC.

For U.S. 76mm APCBC:

100m: 239mm for HVAP, 125mm for APCBC
500m: 208mm for HVAP, 116mm for APCBC
1000m: 175mm for HVAP, 106mm for APCBC
1500m: 147mm for HVAP, 97mm for APCBC"
 
END Rexford material

Here's what I found.
 
Shatter Gap is a real and scientifically documented phenomenon. Paul Lakowski provides the BRL report details and some of the data. Additionally, the US Navy conducted test of the Navy's 3-Inch Gun firing APCBC and found shatter gap was occurring there as well. Both sets of tests identified the critical factors in Shatter Gap. I should advise you that the first time I used the link, I got served up a NSFW wholly unexpected and unwanted Adult Friend-finder ad, but my second attempt got through okay.
 
 
There is a groggier than Rexford discussion of Shatter Gap and a whole series of other matters for naval AP shells vs all sorts of armor types and thicknesses. Nathan Okun is arguably the expert when it comes to naval guns vs warship armor. The piece, taken from the (insert superlatives here) www.navweaps.com site,  references test data, physics calculation and several penetration prediction models, one of which, FACEHARD 6.8, is his. He forthrightly notes deficiencies in his own program's results vs certain firing tests. Provided your head doesn't explode (mine's about to burst after only skimming parts), you will get quite an education on naval terminal ballistics.
 
Regards,
 
John Kettler
 




 
 
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Edited by John Kettler

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What type of armor are the tables based upon? Do they have the same characteristics as the Tiger armor? What is the RHAe of the high-hardness Tiger plate? (They kept that quality up, unlike other tanks.) The Tiger armor's 100mm was a MINIMUM thickness. Often it was a few mm thicker. What about the zimmerit coating? Did that add resistance? Or reduce it? What about hitting things on the front, like brackets, cables, etc? (Then, we can talk about edge effects, too.)

Finally, we also need to realize that the front hull plate was sloped back at 10 degrees from the vertical.

 

The measured thickness of Tiger armor plate was usually 2mm over minimum spec. Zimmerit did not add anything to resistance. High quality 102mm plate of 340 BHN would have resisted about 3% more than US test plate of equivalent thickness. British 6 pdr tests on a Tiger in North Africa showed even higher resistance.

 

I went back and took a closer look at my tests. I measured the exact angle of rotation on the Tiger tanks and found they were rotated at about 12° rather than the 10 I had been assuming. I was actually surprised I got them that close in the first place just by eye-balling it :)

 

102mm plate @ 10° from vertical and rotated 12° (about 16° compound angle) resists 76.2mm APCBC equivalent to 107.4mm at 0°. A 3% boost for high quality 340 BHN plate gives 110.6mm of effective resistance. At 500 meters US 76.2mm ABCBC penetrates 116mm of RHA (US test plate) at 0°. That is a penetration/resistance ratio of about 1.05. That in turn gives an expected penetration probability of 76% (Russian test data) or 89% (US test data). Observed penetration percentage in my tests was 74%.

 

At this point, I'd love to see a summary.

 

In summary the observed performance in Combat Mission is quite reasonable, in my opinion. There are a few caveats. One is that the expected penetration probability does not factor in shatter gap. The game appears to be very forgiving in that respect. Another is that I do not know if the game uses a high armor quality modifier for the Tiger, or if it does that it is 3%. It's in WW2 Ballistics but as we can see with shatter gap BFC doesn't adhere to that work 100%. I also don't now for sure that CM has the Tiger armor plate at 102mm thickness. It could be 103mm for all I know. And lastly, my conclusions assume that partial penetrations are counted as penetrations. If they are not then there is a huge discrepancy between expected and observed results.

 

We're splitting hairs. Really.

 

Yes. Yes we are. And Nidan is mad at me because I've been wasting my time doing this instead of returning PBEM files :P

Edited by Vanir Ausf B

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I'm wading in on this with a bit of trepidation since the lines of battle are already long established and hotly fought over ;) It's been years since I've had to think about what the definition means, so I may be in error. However, as far as I know what follows is correct for CM:

Partial Penetration = no significant part of the round makes it through the armor. I'm not 100% sure if that means not even a tiny fragment makes it through or not, however CM isn't designed to that level of specificity so I don't think it's a point that should be debated. Put another way, there isn't any effective difference between a 1cm x 1cm chunk of round passing through the inside of the armor and a 1cm x 1cm chunk of spalling. In terms of game effect, they are the same.

The primary damage effect from a Partial Penetration comes from spalling or kinetic energy transfer. An example of the latter is a fragile radio that absorbs enough shock from the hit that it is damaged.

So, to the question of what does Partial Penetration mean when compared against real world armor tests? It could be that the game's definition is 100% identical to a specific test criteria, or it could be that CM's is "looser". Based on years of working with Charles on nitty gritty stuff like this, my expectation is that it is "looser" because there is a point of diminishing returns when trying to quantify outliers which, in theory and in reality, are possible.

Steve

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I was looking for the excellent Mark Diehl article from AFV-G2 in which he sets forth the cases for what happens when projectile meets armor, which has some great line drawings with it. Am pretty sure Scribd has that article, but in the process of searching for free sources, I came across this pertinent to the discussion account of vanilla Shermans vs Tiger 1s at Rauray and Fontenay (both in late June of 1944). Though I didn't look at it in detail, the site apparently is a grog fest by one Mobius for a set of Micro Armour™ rules called Panzer War. In any event, there is a great deal of fiddly analysis there, such as back computing ballistic coefficients for shells, but the above is a collection of eyewitness accounts from both sides and a stack of associated photos. There are accounts here I've never seen, and it's fairly unusual, I'd think, to have accounts both from an individual tanker and members of the crew of the tank hit.

 

http://www.panzer-war.com/page45.html

 

Regards,

 

John Kettler

 

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