Long 88mm lacking punch?

[Guest KwazyDog]

I am not going to even begin to discuss any of this becuase I have no expertise in this area but I dont understand why the Jentz figuers stated are considered the figures that should be taken as the last word the guns penetration capabilities...

Can anyone say Patriot? Do you all remember how we were told not one scud had gotten past them without being intercerpted during the gulf war? Now we find that this was indeed true *BUT* the officials decided to redefine the word intercept to mean 'crossing the path' of a scud instead of a true hit and kill.

Now lets say in 50 years someone writes a game on the guld war. Would you prefer they took out a book and went ahhh, the governments published data of 98% accuracy for the patriot must be correct, or would you prefer they researched the performance characteristics, seeker and radar details and came to a more proven conclusion?

Not very relevant I know, but it makes a point. Under these circumstances I see it much better to base your descisions on calculated statistics rather than blind faith.

Anyways, just my opinion, nothing more

[This message has been edited by KwazyDog (edited 08-24-2000).]

[Jeff Heidman]

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

Not very relevant I know, but it makes a point. Under these circumstances I see it much better to base your descisions on calculated statistics rather than blind faith.

Anyways, just my opinion, nothing more

).]<HR></BLOCKQUOTE>

Kwazudog makes a nice post, with good points, and then ruins it by marginalizing his argument.

The choices are not between "calculated statistics" and "blind faith". The arguments presented by John and others are quite convincing, but then, so are the arguments provided by BTS.

Trying to portray one side as reasoned and the other as ridiculous makes you look like you have an agenda, not a point.

Jeff Heidman

[Ben Galanti]

Paul,

I guess the question then becomes, if the Ordinance Board equations do have a flaw in them, what is special about the 88/L71 which causes the ordinance board equations to be incorrect? BTS's argument is that the equations match test results for virtually every other gun in the game, and as such seem to be valid model.

Now, the higher penetration test values may indeed be correct, if so, what is the reason that the equations do not work for this specific gun. Now, if there is more recent research which comes up with a better model (one that matches all the guns in the game) I'm sure BTS would love to see it.

Ben

[Guest Big Time Software]

Ben and others have restated yet again the questions that Paul, Helge, and John continue to dodge. I will lay them out clearly and REFUSE to post anything more to this thread until the question dodging STOPS. Answer the following questions, directly and without out any dodging, one by one and then we can proceed. If you refuse to do this, as you have all along, then it is plainly obvious that you don't know what the Hell you are talking about. Sorry, it has got to the point to call a spade a spade until you stop dodging the questions (ALL the questsions):

1. Do agree that several different, and independently credible, sources have produced different results for the same weapon?

2. Do you agree that it is impossible for different sources to come up with different results if all are based on the same testing standards?

3. Do you agree that it is inherently flawed to pick one set of the credible numbers over another set without any other reason than blind faith that the one you are picking is correct?

4. Do you agree that our physics model is only in dispute in relation to the 88L/71 data that you support. Not to any other data from any other weapon from any other nation?

5. Do you agree that if our equations are incorrect that means that all other data it produces is also incorrect?

6. Do you agree that there is a credible set of test data, for many guns from many nations, that agrees with our mathematical equations' output?

7. Do you agree with the scientific approach that when you have differing data, from credible sources, that you must look to another scientific (or primary source) to explain which of the conflicting data sets is correct?

8. Do you think it is more probably that there is one set of questionable data for the 88L/71 or that all the other test results, for all weapons from all countries, is in error?

9. If our equations are outdated and inaccurate, can you please explain how it is that our results match those of test data from three different nations for dozens of guns? Put another way, how can a flawed set of equations come up with the correct results and still be flawed?

10. Which is more credible; blind faith that can not account for differing data or mathematical results, or a reasoned scientific approach that can account for everything using primary materials AND mathematical computations?

Until you come back with direct answers to the above questions we can not proceed with this debate. You have dodged these questions too many times already.

Steve

[Juardis]

I'm a nuclear engineer, not a physics guy. But in my field we are constantly taking measurements and fitting curves to the data. If we find a curve that matches all the data except one or two points, we call those outliers bad data points. It's as simple as that.

BTS has found a curve that fits all data for all guns from all nations except for the 88L71. The only thing I don't know is this: Is the 88L71 data within the box of all the data (i.e., can you interpolate or must you extrapolate)? If it lies at the edge of the data ranges (extrapolation), then perhaps the curves need tweaking. If it lies within the data ranges (interpolation), then the curve is acceptable. For example, say the edge of the velocity data is 100 m/s to 1500 m/s and the 88L71 is 900 m/s, then a curve that fits all data except the 900 m/s suggests that the data point is bad. It's really that simple to my feeble mind. If you tweak the curve to match the 900 m/s data, then you've potentially screwed up all the other data.

------------------

Jeff Abbott

[Guest Big Time Software]

And no, we are not going to publish our equations, for two reasons:

1. It is not necessary. The case we make is scientifically based and is backed up by primary test data (Aberdeen is primary since they fired the gun using German ammo of the time).

2. This is what is called proprietary information. We have stated the source which our equations are based on. VERY INTERESTINGLY ENOUGH... although we have asked TWICE, Paul has not done the same. And since he is apparently a programmer for a product that is, in a sense, in competition to us, this underscores why we shouldn't be giving away our hard work for free.

And even if we did publish our equations, what does that prove? If they are wrong it would be very easy to prove by picking up published penetration figures for other guns ans showing that there is a pattern of errors in our results. Since you can't do this, you are looking for a straw man argument is the only way to tell what is the truth.

Argh.

Steve

[Vanir]

Everyone should read Rune's post. He makes some great points.

<BLOCKQUOTE>quote:</font><HR>Originally posted by Paul Lakowski:

People stop using the Ordnance board report as good science and physics...NO ONE USES THIS FORUMLA ANY MORE. Ive never seen any reference to it in the 'abstacts' of the papers that I look at.

This is a 50 year old formula , which already makes it suspect, cause no formula survives more than 5 -10 years in the engineering journals before its ripped to pieces and rebuilt to better explain the events. The inconsistancies we've stated above would be more than enough to send the researchers back to the drawing board.

I'sorry but the burden of proof has always remianed with BTS.If I go to some interested third party and say that Jentz , Hogg and others consistantly report the same data for a round of ammo , while this CM game claims -to the death I might add- another completely different value .... who do you think there going to believe? <HR></BLOCKQUOTE>

One more time: The penetration values derived from BTS's physics model closely match the test data for all weapons other than 88L/71, including British and American. And in the case of the 88L/71, 2 sources, Aberdeen and Bovington, support them. If this isn't proof that their models work very well, I don't know what is. It almost seems your trying to hold BTS to an impossible-to-achieve level of perfection.

<BLOCKQUOTE>quote:</font><HR>Origialy posted by PzKpfw 1

No where in this discussion has BTS supplied 1 scientific formula Ie, the type Paul used would suffice detailing how the KwK.43 8.8cm ammunition penetration was derived and found flawed.<HR></BLOCKQUOTE>

BTS would have to be complete idiots to post their formulas on a public BBS. Any competitor making their own game could copy them and save themselves a lot of time and research at BTS's expense.

<BLOCKQUOTE>quote:</font><HR>I am also well aware of other published penetration data, I have tried to narrow the feild down to concentrate on the primary test data, and apperently that is not acceptable, because it rules out useing Aberdeen, Bovington etc, after war equasions which are impoirtant to BTS's claim.<HR></BLOCKQUOTE>

No one has proposed any reason why Aberdeen or Bovington's testing methodologies would have been flawed, therefore there is no reason to believe their data is invalid. Some accuse BTS of promoting their data because it supports their own, but it could be said that others are trying to discredit it for the exact same reason.

<BLOCKQUOTE>quote:</font><HR>What was the criteria for Aberdeen's test results plate BHN etc? and why is Aberdeen more accurate concerning the 8.8cm ammunition performance then, the Germans or Bovington etc,? as you said they all have varying numbers.<HR></BLOCKQUOTE>

Actually, I don't think anyone said that Aberdeen or Bovington are more accurate than the German test, they simply said that there is no reason to believe their results are not perfectly valid.

<BLOCKQUOTE>quote:</font><HR>Their is no attempt to dodge any issue (I know some appear to wish I would) the issue here is a simple quest for knowledge that can easily be settled with BTS provideing their "scientifically derrived formula" equasions concerning their 8.8cm ammunition formula so it can be analysed and a final conclusion based on it. And if stands up; pats on the back, kudo's & you can proudly say 'told you so & your can of worms can be closed.<HR></BLOCKQUOTE>

Well, you answered some of what was being asked, about which set of test numbers BTS should use, though your reasons for selecting those particular numbers over the others are a bit vague and not backed up by solid evidence of their greater reliability. No one has still answered why, if BTS's formulas are as flawed as a few people have said they are, the 88L/71 is the only weapon they can find that doesn't match their numbers.

This is getting kind of silly. This started out as a debate on the penetration values of a single weapon and has turned into an attemt by 2 or 3 people to discredit the entire armor penetration modeling system in CM based entirely on the deviation of that one weapon from the German data. I can see where this is going to end up....

Still, a very interesting thread

[This message has been edited by Vanir (edited 08-24-2000).]

[Guest Big Time Software]

Jeff wrote:

<BLOCKQUOTE>quote:</font><HR>If you tweak the curve to match the 900 m/s data, then you've potentially screwed up all the other data.<HR></BLOCKQUOTE>

EXACTLY. One thing you missed, and I would like to hear your opinion on this, is what you do when 3 or 4 scientists come up with different data. If one or two sets are within the bounds, and the others far outside of it, how do you approach this if a large body of other test data fits within the bounds? Do you:

a. Disregard the conflicting data because equally credible data fits the model and other credible data.

b. Change the equations so that the conflicting data fits the model and that the agreeable set does not, even if this means all the other credible data is now outside of the bounds, based on personal choice alone.

Obviously there is a "c", which is to redo the tests under the correct test conditions again and see where that gets you. Boy, I wish I could do "c" 'cause that would be fun

Steve

[PzKpfw 1]

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

I dont understand why the Jentz figuers stated are considered the figures that should be taken as the last word the guns penetration capabilities...

<HR></BLOCKQUOTE>

Well, as previously stated repeatedly the figures stated are NOT Jentz's they are Wa Pruf etc. And lets say for sake of argument they were his, then I can ask you why BTS chose to use those same figures to prove their point as well.

I have also stated I am in full agreement that other penetration data with inconsistancies does exist & I am not disputing it as I also provided evidence to back it up.

This is not a 'blind faith' discussion to state it is; is conviently dodgeing the issue. As if it was the case; we could say the same concerning BTS's stance on this whole issue. We the much maligned ppl who have questioned this, have been told to accept the BTS formula for penetration above all others; on blind faith; with no mathmatical formula evidence presented to back up the claim.

I have said this before we all see Charles point on the differeing results between the L/70 & L/71 ammunition performance curve.

What has been lacking in BTS's claim is quantifing evidence to support the rest of the assertion that the German wartime results for the 8.8cm ammunition are beyond reproach & irrefutably incorrect, when pressed we have been told their formula matches all other German Wa Pruf penetration data from the same tests .

And that the formula gives a differing value for the KwK.43 ammunition with Aberdeen cited as in total agreement with BTS formula results.

All BTS has to do to settle this is supply us with the mathmatical formula used by BTS to come to their conclusion. The formula could then be studied and compared to more recent ballistical works to obtain an overall assessment of the original claim. Is this that an unreasonable of an request?

Regards, John Waters

--------

"Go for the eyes Boo, go for the eyes!!"

[Juardis]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Big Time Software:

EXACTLY. One thing you missed, and I would like to hear your opinion on this, is what you do when 3 or 4 scientists come up with different data. If one or two sets are within the bounds, and the others far outside of it, how do you approach this if a large body of other test data fits within the bounds? Steve<HR></BLOCKQUOTE>

Well, ideally you would use the measured data from the same scientist. e.g., use all data from Jentz. That way you minimize as many variables as possible. If you develop a curve that fits all data except for one or two points, you can clearly call those points bad.

Barring that, we typically combine ALL data and do a least squares fit that best fits ALL data

OR,

we break the data up into finite ranges and develop multiple curves depending on where the conditions are. e.g., between 100 m/s and 500 m/s, use curve "a". between 500 m/s and 1000 m/s, use cuve "b". etc. But doing either one of these obviously still results in a bad data point being a bad data point.

To me, your 88L71 numbers represent a least squares fit through ALL the data and hence is most acceptable. JMO.

to answer your question - I choose "a"

------------------

Jeff Abbott

[Guest Big Time Software]

<BLOCKQUOTE>quote:</font><HR>This is a 50 year old formula , which already makes it suspect<HR></BLOCKQUOTE>

Except for one crucial point, Paul: that the formulae we use correctly match all test data we've come across except for the data from the 88 L/71, which for all the reasons listed above (which you continue to dodge, even though we challenge you directly to refute them) are clearly suspect and inconsistent.

For a 50-year old formula, that's pretty good. It matches everything except one set of data that is clearly frought with problems itself.

<BLOCKQUOTE>quote:</font><HR>I'sorry but the burden of proof has always remianed with BTS.<HR></BLOCKQUOTE>

There you go again, dodging the issues.

We have demonstrated our case by citing successful formulae and presenting evidence that undermines the believability of the published data for the 88 L/71. All you have presented is your blind faith in the printed word, and nothing more.

Since we have presented a full case, and you have presented no evidence whatsoever, the burden of proof now lies with you.

<BLOCKQUOTE>quote:</font><HR>If I go to some interested third party and say that Jentz , Hogg and others consistantly report the same data for a round of ammo , while this CM game claims -to the death I might add- another completely different value .... who do you think there going to believe?<HR></BLOCKQUOTE>

You know, on this very message board people challenged the armor rating of the Tiger I mantlet. I had originally rated it at 100mm. Why? Because Jentz said so. And I believed him. It turns out that Jentz corrected himself in one of his later books, raising the value to 120mm. But people on this board presented convincing evidence that even this was not sufficiently correct! There is some overlap between the mantlet and turret front, and the mantlet is not of an even thickness. So some new tailored code was needed to handle the Tiger I in CM.

Up to that point I had put blind trust in the Jentz numbers just like you are right now. It turns out that Jentz was wrong in this case. Others presented good evidence, and they convinced me. Lesson learned: even excellent writers like Jentz sometimes make mistakes.

You would do yourself a service not to have such blind faith in the printed word.

<BLOCKQUOTE>quote:</font><HR>No where in this discussion has BTS supplied 1 scientific formula Ie, the type Paul used would suffice detailing how the KwK.43 8.8cm ammunition penetration was derived and found flawed. <HR></BLOCKQUOTE>

John, please start reading our posts in their entirety. I will quote myself here, taken from the first page of this thread:

<BLOCKQUOTE>quote:</font><HR>How do I reach this conclusion? The simple physics behind it. Combat Mission does not use "penetration tables" or charts to determine armor penetration. Instead it uses the mathematical equations described in "Penetration of Armour Plate" originally by (British) Ordnance Board Subcommittee of the Armour Piercing Projectile Committee (reproduced by U.S. Dept. of Commerce National Technical Information Service #PB91127506).<HR></BLOCKQUOTE>

I promise that this research paper has lots of formulae in it. Go ahead and read it for yourself - it's all public information. We are not hiding anything here. Your saying otherwise is complete bunk.

<BLOCKQUOTE>quote:</font><HR>and why is Aberdeen more accurate concerning the 8.8cm ammunition performance then, the Germans or Bovington etc,? as you said they all have varying numbers.<HR></BLOCKQUOTE>

No one said that Aberdeen is better. All we said is that all the numbers differ to an alarmingly great degree and therefore the whole lot of them is suspect to say the least. Please do not try to obfuscate that very simple point. I think I have repeated it about ten times now and I think it still isn't sinking in. And you're still dodging it.

<BLOCKQUOTE>quote:</font><HR>& It does effect all German tests even if only in credibility; you cant have it selectivley effect what you wish; even if your numbers match<HR></BLOCKQUOTE>

We don't, because CM - I will say this YET AGAIN because some people aren't listening! - DOES NOT USE TABLE-BASED PENETRATION DATA!

The other test data was mentioned only in the sense that our formulae matches them almost perfectly. It is NOT our conention that ALL wartime test data is junk. I think that the majority of it is good. Based on that, it is reasonable to use a formula that matches as much of the wartime test data as possible. I found no such formula that could explain sets of data for the 88 L/71 that do not agree with themselves, however.

I would like to remind you that our formulae work perfectly well with projectiles that travel at a higher velocity than the 88 L/71. They also work with all those at a lower velocity. If you can tell me what makes the 88 L/71 somehow different, please do so. You have failed to provide this key piece of evidence so far.

<BLOCKQUOTE>quote:</font><HR>All BTS has to do to settle this is supply us with the mathmatical formula used by BTS to come to their conclusion.<HR></BLOCKQUOTE>

I refer you YET AGAIN to "Penetration of Armour Plate" reproduced by U.S. Dept. of Commerce National Technical Information Service #PB91127506. That's at least the third time I've mentioned this paper in this thread alone, and I know I've mentioned it elsewhere too. How many more times will I have to mention it before you see? Are you actually reading my posts?

Charles

[This message has been edited by Big Time Software (edited 08-24-2000).]

[Guest rune]

And the debate goes on...

So...since Aberdeen and Bovington's tests were questioned, why not ask them? So...I did...i just finished e-mailing people there to see if I can get any information on their testing of the 88L71 gun. I also asked if the 1950 formula is flawed, as I also did to the US Army Ordinence Department. IF they answer, and I hope they will, I will post their answer here. HOWEVER, I am sure all three have better things to do, but here is to hoping the will answer about their tests. I also invited them here to read the thread. I will copy/paste any reply I get.

Rune

[Guest rune]

How is this for speed to an answer:

Sir: Sorry, the documents needed to answer your question were transferred to the national archives back in the 1970s. I am afraid we do not have anything here that we can consult to give you any sort of answer at all.

Awaiting a reply from Bovington and The Army.

Rune

[Guest Mr. Johnson-<THC>-]

Charles and Steve,

Why are you letting these guys suck you in. Your have stated you reasoning for making the decisions you have while making YOUR GAME. These people obviously just want to make you pull your hair out. They don't make any valid points, why waste you time and energy? If they have a prob with the 88 lang not penetrating at long range as much as they "THINK" should, instead of asking GOD ie Steve&Charles to give them the ubergun to kill satan, why don't they as a commander fiqure out a way to win a battle under those constrants? They obviously want to go play Command and Conquer 2:TS and use the hand of nod all night long, then be forced to make tough command decisions.

[Guest Mr. Johnson-<THC>-]

Charles and Steve,

Why are you letting these guys suck you in. Your have stated you reasoning for making the decisions you have while making YOUR GAME. These people obviously just want to make you pull your hair out. They don't make any valid points, why waste you time and energy? If they have a prob with the 88 lang not penetrating at long range as much as they "THINK" should, instead of asking GOD ie Steve&Charles to give them the ubergun to kill satan, why don't they as a commander fiqure out a way to win a battle under those constrants? They obviously want to go play Command and Conquer 2:TS and use the hand of nod all night long, then be forced to make tough command decisions.

[PzKpfw 1]

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

Everyone should read Rune's post. He makes some great points.

Well, you answered some of what was being asked, about which set of test numbers BTS should use, though your reasons for selecting those particular numbers over the others are a bit vague and not backed up by solid evidence of their greater reliability. No one has still answered why, if BTS's formulas are as flawed as a few people have said they are, the 88L/71 is the only weapon they can find that doesn't match their numbers.

<HR></BLOCKQUOTE>

Well I tried & have used what exsits (which isn't much) as evidence to my point, exactly the reliability is not in the numbers but the test process. Its not that the formula is flawed its their conclusion based on highlighting the 88L/71 as & the only flawed example.

<BLOCKQUOTE>quote:</font><HR>

BTS would have to be complete idiots to post their formulas on a public BBS. Any competitor making their own game could copy them and save themselves a lot of time and research at BTS's expense.

<HR></BLOCKQUOTE>

Then further discussion on this topic is moot, as it can simply be said, this is the way it is we are right & your wrong to bad, because our evidence is secret. the basic formula is already available for purchase thru NTIS all that is required is to post the mathmatical formula & associated graphs used to draw Charles conclusion.

<BLOCKQUOTE>quote:</font><HR>

No one has proposed any reason why Aberdeen or Bovington's testing methodologies would have been flawed, therefore there is no reason to believe their data is invalid. Some accuse BTS of promoting their data because it supports their own, but it could be said that others are trying to discredit it for the exact same reason.

<HR></BLOCKQUOTE>

Aberdeen & Bovington came up later the original argument was Jentz vs Jentz. How do you propose we question the testing methodologies Vanir? the type of formula used by both places is over 50 years old and outdated in the ballistic feild, todays works do not deal with WW2 ammunition they deal with APFSDS-DU HEAT etc.

To actualy research this topic leaves you with maybe 3 various governments immidiate after war reports. One of them being the British 1950 Armor Penetration Report used in CM, this report contains all the known data available in 1950 which BTW is allegedly flawed in its angle/slope equasions.

Its not a attempt to discredit anything the specific argument here is figures as used by Charles in his original post. & I could care less who is right or wrong as long as some answer is reached.

<BLOCKQUOTE>quote:</font><HR>

Actually, I don't think anyone said that Aberdeen or Bovington are more accurate than the German test, they simply said that there is no reason to believe their results are not perfectly valid. <HR></BLOCKQUOTE>

I agree on this to a point one could make the assumption they are from the posts Ie, Aberdeen data matches BTS data concerning the L/71 ammunition Bovington data is the 1950 report. Charles etc could be very well correct or they could be wrong as could I etc, it just remains to be seen who is either way I'd think their'd be an interest in this being resolved either way.

<BLOCKQUOTE>quote:</font><HR>

This is getting kind of silly. This started out as a debate on the penetration values of a single weapon and has turned into an attemt by 2 or 3 people to discredit the entire armor penetration modeling system in CM based entirely on the deviation of that one weapon from the German data. I can see where this is going to end up....

<HR></BLOCKQUOTE>

Dunno what your talking about Vanir I have made know attempt to discredit BTS in anyway I have questioned the statement that the penetration test data is invalid and tried to get some viable proof for further study.

I see where its going to & yes it has been a very interesting often heated discussion with valid points from everyone, and is an great example of the problems concerning how complicated penetration research realy is. I also commend BTS to sticking to their guns even if lacking the formula used to draw my own conclusions.

Regards, John Waters

-----------

------------------

People who can smile when things go wrong

have found someone else to blame.

[JoePrivate]

Charles and Steve, you have done an admirable job presenting and explaining your position, repeatedly. Even to a layman like me it is crystal clear, I congratulate you for taking the time and energy to do so. I too wonder why the people disputing your conclusions refuse to acknowledge your points. I see no reason to continue with this debate until they do.

Helge, no matter how well you insinuate 'something is up' or believe in the art of blowing smoke, it is still smoke to the rest of us.

[PzKpfw 1]

Originally posted by Big Time Software:

Point taken Charles I don't know where the bunk statement came from in my mind it was an valid question .

I am going to focus my efforts on the 1950 Report and will refrain from posting except rebuttals until such time as I learn what I can from it and draw my own conclusion. But Charles if I was incorrect in my assertions I will be first to admit it.

Anyway Thx to Charles & Steve for actualy putting up with all the data flying around here & I hope you do understand that my questioons stem from my fondness of CM & WW2 ballistic tests, not in any plot to discredit BTS etc.

Regards, John Waters

---------

"Go for the eyes Boo, go for the eyes!!".

[Guest Big Time Software]

JoePrivate,

<BLOCKQUOTE>quote:</font><HR>Charles and Steve, you have done an admirable job presenting and explaining your position, repeatedly. Even to a layman like me it is crystal clear, I congratulate you for taking the time and energy to do so. I too wonder why the people disputing your conclusions refuse to acknowledge your points. I see no reason to continue with this debate until they do.<HR></BLOCKQUOTE>

Thanks Joe. I'm starting to have the same feelings.

I will say the following as a brief summation of our arguments (anyone wanting more detail should read this thread in its entirety). And I won't post any more unless some new information appears.

We base the conclusion that the 88 L/71 data is flawed because it is:

1. Internally inconsistent to an alarmingly and suspiciously high degree, and

2. An "outlier" from the formulae we use. These formulae are credible because they successfully predict penetration for every other gun in the game, both those with higher and lower velocities than the 88 L/71. No evidence has been presented to show that the 88 L/71 is somehow 'special'.

Charles

[Scorpion]

My materials science and aerodynamics courses were a long time ago, so I will not pretend to be knowledgeable of the subject matter.

However, I fail to see the reasoning (if it is there) behind one side of this debate.

BTS has a formula which closely matches the penetration data of several countries, and most guns. The data for one particular gun, the 88/71, is inconsistent and varies wildly across testing, and does not match that which the formula provides.

So, among the different reasons why this could have happened, I see three strong possibilities: First, the formula is wrong, and does not model armor penetration close to reality. Second, there is something special about the 88/71 gun which makes it perform differently than the assorted other guns tested and modelled. Third, the formula is a decent model for armor penetration, so there must be an error in the collected data, or the collection method.

I feel that the first case is the least possible of the three. If we are to take BTS at their word (and why would they have reason to not be truthful?), their formula data matches that of the assorted countries' collected data for all but the 88/71. To 'prove' the point, others have asked for the formula to be published. What is the motivation behind that? BTS never had to prove anything; their formula stood tall for all guns until someone decided that the 88/71 penetration must be wrong, formula be damned. Could the motivation be that the debator has no means of defending his point other than a long shot hope that the formula contains some glaring error? Or perhaps a potential competitor wants to take a peek at the inner workings of the game, or obvious reasons?

BTS has provided their source - I would suggest deriving the formula yourself. However, before looking at the formula, answer this: How could the formula be in error if its results are a best fit curve to the wartime data collected by the assorted countries in ALL CASES BUT ONE?

The second case seems more likely than the first, at least it is based on something plausible. However, the suggested differences in the 88/71, that of the high velocity of the round having a special effect upon the penetration at impact, are again inconsistent with data (and formula results) for both lower and higher-velocity guns. Is there some reason that the 88/71, and the 88/71 ALONE (not "high velocity" weapons in general, just that one gun) is different from others? So far, I have yet to see a logical conclusion drawn regarding this.

Therefore, to me the third case is the most likely. It is entirely possible for the data to have been incorrect, to have been fudged, or even copied incorrectly for one gun. The possibilities of why this might happen are endless. This is assuming that someone were taking the German wartime data as the best source for armor penetration figures. In this case, BTS' formula stands up to all but one set of test data - the 88/71.

Until someone suggests a valid reason for why the 88/71 differs greatly from other weapons, I see no reason at all for BTS to even question the formula they have.

While I normally would agree with Helge, that hard data is usually better than formula-generated results, I cannot in this case. This is because the "hard data" is not necessarily fact, when considering the testing was done almost 60 years ago, by various persons of unknown skill and unknown motivation. The data itself has been transcribed, translated, and/or copied numerous times. Perhaps someone, either the engineers performing the tests or those transcribing the data, had reason to fudge the numbers. Perhaps someone just made a simple mistake. Perhaps people in the military at the time "felt" the actual data was wrong because of how effective the King Tiger seemed to be on the field. Whatever happened, I find it much more plausible that the data for a single gun is in error rather than all of the data becoming suspect.

In addition, the definition of a straw man argument is when someone chooses to attack an argument which is different from, and usually weaker than, the opposition's best argument. If you choose to say that BTS is putting in doubt German wartime data in its entirety when they are simply implying that there could have been ONE outlier in the whole body of data, that is a straw man argument.

I have no idea why this debate has gone on so long. Is it because people have a gut 'feel' that the King Tiger should be performing better, and thus are looking for anything to prove this? Or are people just being contrary?

In any case, the burden of proof has always been on those people who are calling into question the validity of BTS' findings. Until now, BTS' formula was accepted as a close-to-reality model for armor penetration. You are saying, at least in the case of the 88/71, that it is not, and thus YOU MUST PROVE WHY THIS IS SO.

Cheers,

-Scorp

[Jeff Heidman]

ON a related note, does any of these argued about sources emntion the probabilty of penetration, rather than jsut these boolean statements?

It is one thing to say that X gun penetrates Y armor, but there is never anything along the lines of X gun penetrates Y armor Z percent of the time.

Compared to ASL, CM seems to me to be pretty deterministic in its penetration formulas. Whether or not that is good or bad is debatable, but I would like to know what BTS used to decide how to model the fickle finger of fate in armor penetration, since it seems like the studies do not really address the issue.

Jeff Heidman

[Vanir]

<BLOCKQUOTE>quote:</font><HR>Originally posted by PzKpfw 1:

How do you propose we question the testing methodologies Vanir? the type of formula used by both places is over 50 years old and outdated in the ballistic feild, todays works do not deal with WW2 ammunition they deal with APFSDS-DU HEAT etc.<HR></BLOCKQUOTE>

Actually, I'm not proposing we do anything of the sort, since as you point out, this is probably not feasable anyways. All that I was saying was that a: the differences in the various data for the same gun strongly suggest differing methods or materials. b: Without going back in a time machine there is no way to know for sure whose results are the most representative of actual battlefield performance. This is what Steve was talking about when he spoke of the dangers of accepting test data without knowing these things; ("blind faith") as he put it.

<BLOCKQUOTE>quote:</font><HR>One of them being the British 1950 Armor Penetration Report used in CM, this report contains all the known data available in 1950 which BTW is allegedly flawed in its angle/slope equasions.<HR></BLOCKQUOTE>

According to who? I admit I may have missed this earlier in the thread, but I don't recall this flaw coming up before.

<BLOCKQUOTE>quote:</font><HR>Dunno what your talking about Vanir I have made know attempt to discredit BTS in anyway I have questioned the statement that the penetration test data is invalid and tried to get some viable proof for further study.<HR></BLOCKQUOTE>

Ah. I'm glad you cleared that up. Notice I did say 2 or 3 That was because I wasn't sure where you were going with this.

Actually, we want the same thing: as good a game as we can get. I'm only sticking up for BTS because their arguements in favor of their curren system have struck me as very logical and well reasoned. If some one does come up with solid facts saying their wrong I'll admit it as I suspect Steve and Charles will as well. You are correct that for those who still think something is amiss, a carefull study of the British report is the only way to go.

Well... time for some CM!

[This message has been edited by Vanir (edited 08-24-2000).]

[Paul Lakowski]

The reason the 88L71 could have different results from the test is because the ratio of the tip to the ratio of the body of the round is about 6-7:1 while the ratio of the Tip to body of most other german APCBC rounds is 4:1

In the test that Brooks did this difference could be signififcant . In addition the tests with various materials showed no correlation between increasing density or hardness and increasing penetration infact in some cases the opposite occured.

In addition Brooks work showed that the hardness of the cap had as big an impact on the penetration results as did varing the tip radius....in the transitional zone.

This ratio may well explain the superior performance of WC penetrators as they reach tip to body diameters of 14:1 or more.

Sources:

"Ballistic Impact - The dependence of the hydridynamic transition velocity on the projectile tip geometry"

PN Brooks Def,Research Est, Valcartier Quebec. Oct 1974.

"Ballistic Evaluation of Materials for Armor Penetrators"

PN Brooks & WH Erickson ef,Research Est, Valcartier Quebec. Oct 1971.

At this point these are the most important as they deal with 'ogive penetrators 4.5:1 L/d striking at 1400-4500 ft/s'. But theres also evidence of something funny going on with steel 3:1 cylinders penetrators at around 1000m/s impactimng IT 80E plates in

A Tate's 'Long Rod Penetration models - Part II extensions to the Hydrodynamic theory of penetraion RARDE 1986 , Int.J.Mech Sci Vol 20, pp 599-612.

I'll start searching the jounals for more AP data as normally I'm just interested in long rod penetrators and shaped charges. Since half the papers in these journals are about AP projectiles @ sub ordnance and ordnance velocities it shouldn't be too hard.

[IntelWeenie]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jeff Heidman:

Compared to ASL, CM seems to me to be pretty deterministic in its penetration formulas. Whether or not that is good or bad is debatable, but I would like to know what BTS used to decide how to model the fickle finger of fate in armor penetration, since it seems like the studies do not really address the issue.

Jeff Heidman<HR></BLOCKQUOTE>

Don't know what they used, but the 'fickle finger of fate' (I like that! ) is definitely there. Don't know how else Tigers can bounce rounds off of the turret of an M8 Greyhound. (happened to me once or twice)

------------------

"Belly to belly and everything's better" - Russian proverb

[Lee]

Steve and Charles have more than proven their case here. The formula

they use has great weight and credibility because it gives results

that match the best test data for every gun from every country in CM,

except the 88/L71. This proves that the formula is very accurate

and reliable. If it wasn't, then it's output wouldn't match 99.9% of

the original test data for armor penetration of guns in CM. This is

just a simple fact. And the fact that at least one set of test

data matches CM's figures for the 88/L71 gives them even more weight.

The *only* way that CM's penetration figures for the 88/L71 could

be shown to be wrong would be if someone could present clear and

powerful evidence of some factor or factors that makes the 88/L71 and/or

it's ammunition special in some way that the CM formula doesn't account for.

So far, absolutely no such evidence has been given. And until this

evidence is presented, there is no valid or logical argument to be

made against CM's penetration figures for the 88/L71.

[This message has been edited by Lee (edited 08-24-2000).]