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The DesertFox

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  1. Thanks for the input guys.

    Sgt Steiner,

    I guess it´s the same as "A Time for Trumpets : The Untold Story of the Battle of the Bulge", that´s the one I have. A very interesting book, perhaps one of the best on this topic besides "The Bitter Woods" by Eisenhower and Tolands "Battle : The Story of the Bulge"

    Cheers

    Helge

    PS: Anyone who has someting about "The Mighty Endeavor : The American War in Europe" ?

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    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

  2. Hi,

    Bob Cunningham and I have put together our data in the past and present the stuff on a webpage.

    http://www.geocities.com/Area51/Capsule/2930/NahVtdgW/artnahvtdgw.htm

    This is pretty much all what is published about the device and it´s ammo.

    Charles is aware of the data and AFAIK has reduced the effect which was calculated as a 92 mortar shell which is, that´s what published data suggest, way too much.

    I don´t know on which level the effect is calculated right now, but it should be somewhere between a Handgrenade and a Gewehrgranate, more close to the Handgrenade.

    Cheers

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

  3. Hi,

    Can anyone recommend these two books ? I´m wondering because many Authors refer to them or cite them. I have "Company Commander" and "Time for Trumpets" myself and found them a very interesting read. How do these two compare to them ?

    Last Offensive : United States Army in World War II the European Theater of Operations

    Von: Charles B. MacDonald

    The Mighty Endeavor : The American War in Europe

    Von: Charles B. MacDonald

    Cheers

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

  4. Whoops Ari,

    Correct. My bad. Sorry. I have indeed confused the values.

    My apologies for confusing these values. I feel very embarrassed about it. Please forget the story about the 76mm. My above statement was basing on my erronous assumption and indeed is wrong.

    The correct values are [hopefully without typo] :

    APCBC...........CM@30..........AP-M79.............APC-M62

    Range...........CM@30..........Hunnicutt@30.......Hunnicutt@30

    500.............89............109................93

    1000............82............92.................88

    2000............75.............64.................75

    APCR............CM@30..........HVAP-M93

    Range...........CM@30..........Hunnicutt@30

    500.............175............157

    1000............149............135

    2000............100.............98

    cheers

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

  5. Ari,

    <BLOCKQUOTE>quote:</font><HR>Is this the gun in upgunned Shermans?<HR></BLOCKQUOTE>

    The gun which is modelled in CM is meant to be the 76mm Tank Gun M1,M1A1, M1A1C and M1A2 [76mm/L55].

    This gun was fitted on the Shermans and was ballistically almost identical with the 3in Anti-Tank Gun M5 and M7 of the M10s.

    Now look how the stats compare. See the difference? I fear that it might be the same problem as with the 88L/71. A problem somehow related to the calculation of the slope effect. I guess the 0deg values might be pretty close to each other but after the slope calculation....

    APCBC...........CM@30..........AP-M79.............APC-M62

    Range...........CM@30..........Hunnicutt@30.......Hunnicutt@30

    500.............112............109................93

    1000............101............92.................88

    2000............93.............64.................75

    APCR............CM@30..........HVAP-M93

    Range...........CM@30..........Hunnicutt@30

    500.............219............157

    1000............185............135

    2000............132.............98

    Because of this difference I mentioned the 76mm M32 gun of the Walker Bulldog which without doubt had higher penetration capability as the 76mm M1 gun of the Sherman [76mm]. But I don´t have detailed penetration stats for the 76mm M32, however they aren´t necessary to see the diferences above.

    The Walker Bulldog 76mm M32 gun was introduced in 1950, fired the M339 APBC-T shot, the M319 APCR-T and the M331A2 APDS-T against hard targets and was well able to deal with T54/55.

    The M41 was developed from the T37 series of light tank design and by 1953 the M41 Bulldog had totally replaced the M24 Chaffee. The M41 was highly effective against North Vietnamese T-54/55 tanks in the Vietnam war with its 76mm gun. However, in Vietnam the M41 suffered from being too light for most traditional battlefield support tasks and too heavy for most internal security tasks.

    The M32 gun could hurl a 15 pound AP shot down range at 3200fps, or even faster with hypervelocity armor piercing ammo (HVAP). Maximum rate of fire was said to be around 12 rounds per minute and maximum range was greatest for this type of round, nearly 23,000yds. Effective range was limited to less than 2,000 for anti-tank hunting due to the gun accuracy, but this was more than sufficient for killing T-34/85s that were expected to be the main target for this tank. When the Soviets produced the T-55 with its increased armor and bigger gun, the Bulldog's gun was outclassed, and something bigger had to be called upon to deal with the new Soviet "threat".

    Some stuff about the M41 can be found here : http://www.fas.org/man/dod-101/sys/land/m41.htm

    and here : http://www.kithobbyist.com/AFVInteriors/m41/m41b.html

    cheers

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

  6. <BLOCKQUOTE>quote:</font><HR>Geez, Helge you just can't do that. These guys all got their info from someone elses tests. Are they the same original source or different ones? Did they do their own analysis of the raw data or do they use the analysis given by the guys testing? You may be right but it is impossible to know from what you say.<HR></BLOCKQUOTE>

    Actually I can and the outcome should be pretty close to the results which are produced with the mathematical solution, IF....IF the mathematical solution is able to sufficiently accurate describe the event all results should fit within the tolerance.

    <BLOCKQUOTE>quote:</font><HR>???? You are just obscuring the issue by that statement. I fail to see how all the german tests in WW2 could be considered as one homogeneous entity. Why should they be considered as such? Even with each gun and ammo type there may have been multiple tests.<HR></BLOCKQUOTE>

    Sure you have multiple tests. What do you think, how many testshots are sufficient to produce a firm result ? Perhaps what you mean is standardisation of the lifefiring trials ? This indeed has to be made to minimize all variables you can control. IIRC some of the standardprocedures used by Waffenpruefamt have been posted in this thread.

    <BLOCKQUOTE>quote:</font><HR>Hypothetically speaking would you consider someone 'concerned' about the results of one experiment as having challenged the credibility of them all even when they are quite distinct? Your answer should prove illuminating.<HR></BLOCKQUOTE>

    It depends on variation. If testparameters are standardized the testresults should follow a normaldistribution. If the result in question is within the normaldistribution...no problem, if it isn´t, something is wrong.

    Helge

  7. <BLOCKQUOTE>quote:</font><HR>You can piss on science, logic, and common sense all you want, but it is making little favorable impression of you or your abilities.<HR></BLOCKQUOTE>

    It would be desirable if it would be possible to agree that we are NOT discussing anyones abilities here. Actually I don´t care what you think the above stated impression might be.

    Such comments aren´t very helpfull discussing the matter in question.

    Or do you want me to go down to the level of speach you have chosen ?

    I certainly will not do that. So please drop it, otherwise one might get the impression that if you can´t attack the argument you have to attack the person.

    The question remains and no factual proof has been brought to light how you backup your questioning of the WaffenPruefamt data except with your mathematical solution.

    Helge

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

    Oh my wink.gif

    Charles, Steve,

    I understand all your points made, that your formula matches the data you have available from Bovington and Aberdeen except the 88/L71. That you have chosen to base your formula on this 50 years old report and that you think we have too much blind faith in Jentz data. That´s all fine for me, believe me I can live with that. But that´s not the point here.

    You indirectly question the credibility of commonly accepted primary source material and the work of quite a lot of very credible people if you take the liberty to back up your data with german penetration test result data for the 88/L56 and 75/L70 but refuse the 88/L71 data because it doesn´t fit your formula.

    To the results your formula is producing concerning all other guns which are in the game. I took the liberty to compare the results the CM engine is producing with the data wich is commonly available at David Honners Website [http://www.wargamer.org/GvA/]. The sources for his data are publicly stated and are basing on the well accepted publications by Chamberlain, Gudgin, Hogg, Hunnicutt, Gander, Jentz, Spielberger and von Senger and Etterlin to name a few. I put all the 30 degrees data into one Excel file to grafically analyze it. [i know that this method isn´t holding scientific standards, but you easyly can see tendencies]. Bottomline is that the results your formula produces have a perfect fit with the german data in case of the 88/L56 and the 75/L70, furthermore for the US 75/L40 but hugely differ [even more than the 88L/71 values in question do] in other cases.

    So what do I have to believe ? The data which is published from well accepted authorities in the field or the data your formula is producing ?

    Do you want me to send you the file or do you want to compare the data yourself by extracting them from David Honners website ?

    BTW: If you would say you don´t want to change the data because you don´t feel the need out of gamedesign decisions that´s fine for me, as I already said earlier in this thread . But arguing the credibility of LF testresults in one case and backing up your point with them in another case makes me scratch my head.

    Helge

  9. Charles,

    You have to normalize the data. What you did is...ummm...certainly not normalizing. You need to read the reports to be able to normalizing the data. Of course that will take time.

    However to make it short. You are right the WO 219 LF test and the Bovington test do significantly in huge areas differ from the WaPrüf reports. Now you only have to find out WHY and you will be close to solving a miracle.

    You know what ? What do you think WHY german pentration tests results have been established as a standard when you want to discuss this matter ? There is a reason.

    Nevertheless I am not going to waste my time trying to hint you that something with your formula might be the reason for the obvious non ability to reproduce test data.

    And you are right if you assume that in this case my trust in established test data (and it isn´t that the Jentz figures are the only ones) is much greater than in artifical mathematical produced figures.

    You have your point of view, and others have theirs. Only thing you really should not do is publishing the penetration figures produced by your mathematical solution and question established test data with it. You will experience some surprises if you do that.

    Once again I want to point out one thing clear. This is no gamekiller for me. The positive aspects of the game hugely predominates this issue. Although Steve seems to think something else wink.gif

    Case closed for me.

    Helge

  10. <BLOCKQUOTE>quote:</font><HR>Their is a bigger issue here apperently no one sees but me, if the 8.8cm data is flawed then ALL German ammunition test results are flawed as the same criteria was used for all German ammunition<HR></BLOCKQUOTE>

    Exactly that is the issue we have to solve. [but I fear we won´t be able to]

    For subtantiating that claim hard facts are necessary and not artifical gameengine mathematics, may they produce 80% correct outcome compared to LF testresults or not.

    You have hit the nail on the head [as we say in germany].

    Helge

  11. <BLOCKQUOTE>quote:</font><HR>I feel like I am arguing with a brick wall here<HR></BLOCKQUOTE>

    Seems like we are feeling the same here.

    <BLOCKQUOTE>quote:</font><HR>I did a test. I wrote up results. So I guess my results are accurate and are beyond questioning? Your statement would suggest so.<HR></BLOCKQUOTE>

    No the results are correct. Your reasoning isn´t. That is!

    Compare and normalize all published penetration data for the 88/L71 and find out which differ and which don´t. You easyly will be able to find out that only your artificial data differ and the Bovington´75 data. Now what is your reasoning ? All data are wrong except your artificial ones and the data from Bovington ?

    <BLOCKQUOTE>quote:</font><HR>Good lord... what the Hell am I doing here wasting my time here for.<HR></BLOCKQUOTE>

    Exactly the same am I asking myself

    Helge

  12. <BLOCKQUOTE>quote:</font><HR>Not pass it off to prove or disprove on ppl who disagree or don't understand, in this case the byrden of proof that the German wartime penetration test data lies on Charles.<HR></BLOCKQUOTE>

    100% agreement here. Otherwise you can claim the earth is a table and have others to bring the proof it isn´t.

    Helge

  13. <BLOCKQUOTE>quote:</font><HR>if you have two sources and we have two sources I fail to see why you feel so confident that you can choose one and call it right (and ours wrong) wihtout any other reasoning other than "I like it better". <HR></BLOCKQUOTE>

    Steve,

    You may not want to realize it but your above statement holds true vice versa as well wink.gif

    To the sources: You find them all in this thread, but the detail analysis is YOUR work. I only can point you in the correct direction. If you want to go the other way, well fine, after all it´s your game.

    <BLOCKQUOTE>quote:</font><HR>That isn't very scientific when compared to our mathematical model that not only is backed up by one 88L/71 test result but also matches all the other test results<HR></BLOCKQUOTE>

    Scientific ? No Steve please don´t let us go this way. Don´t tell me (I´m Scientist and working in R&D for years now) what is scientific and what isn´t. You don´t want me to say if I think your attitude towards the matter in discussion can stand scientific standards, want you ? wink.gif

    The problem with your mathematical solution is that it doesn´t seem sufficiently refined to descripe real world events. You don´t want me and others to dig into the other penetration results which are produced by this formula and compare them with real world results, want you ?

    The problem here seems to be that your formula is underestimating the complexity of penetration events. At least it isn´t possible to describe ALL real world results with it. That´s no big issue for me, because as I have stated above, If someone can come out with such a formula which sufficiently accurate can describe real world results that would make this man a real rich man, because this formula would make firing trials obsolete.

    But as stated previously I don´t feel we will come to an agreement here at least until one side or the other will be convinced. As it is right now I totally fail to see any proof (that is necessary here) for your claim that the german 88L/71 WaPruef reports and the other test results are wrong.

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

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

  14. Steve,

    Cool argumentation wink.gif

    Someone might want to contact RHEINMETALL, I bet they are interested in a formula which can save them money for penetration firing trials. wink.gif

    Seriously,

    The reason for development of the 88L/71 was to go to the maximum limit of penetration possible at a given caliber. You really think they developed a gun back then which brings essentially the results your formula produces ?

    Well, I take the liberty to doubt that, because it is NOT only the results of the WaPruef reports which are quoted by Jentz which show otherwise but there are additional published data for the 88L/71 available which are basing on independent tests. Bottomline is that all these firing trials give the 88/L71 a performance which is within milimeters of the WaPruef reports, with one [AFAIK, I could have missed some reports here wink.gif] exception. That is the 1975 Bovington report, which gives the 88/L71 more or less exactly the performance your formula is calculating.

    Now the question remains, Is it that your formula is correct and several firing trials have produced wrong results or is it that your formula is incorrect and the Bovington´75 report publishes wrong results ? Compare the 75L/70 results I have quoted above.

    However I feel we won´t change the matter here. Bot sides have their arguments and seemingly aren´t willing to accept the points the other side has made.

    But one more remark you might want to check. It occurs to me that the 76L/55 US M1 gun you have in the game is more like a representation of the 76/L62 on the Walker Bulldog which was built in the 1950's ? Why is that ? I could be wrong of course wink.gif

    And please don´t misunderstand all this talk about the game as an attempt to smash it. No that isn´t the intention. It merely is a sign that we all love this game and want it to be as close to realism as possible. You know if we don´t find some big bugs to pick at we start to analyze the details.

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

  15. Well,

    It´s pretty easy. If a tank throws one track it still can move, BUT VERY BIG BUT...<G> it only can drive in a circle, because only the one track which is left drives the mass of the tank forward and the other side [without track] is only roling on the roadwheels which have no connection to the drivesprocket [the connection is the track].

    I hope my english is good enough to make the principle clear wink.gif

    Helge

  16. Might be some of you haven´t noticed, but the values CM chooses right now, do pretty much fit with the values of the 1975 Bovington report I quoted above.

    ______CM_____Jentz_____Hogg____Bovington´75____WO185____WO219

    range

    100m 177mm 202mm

    500m 165mm 185mm 182mm 167mm 184mm 178mm

    1000m 151mm 165mm 167mm 153mm 169mm 140mm

    2000m 121mm 132mm 139mm 139mm 121mm

    Talk about coincidence.

    And things are REALLY starting to get interesting if we compare the figures of this Bovington´75 report with the Jentz figures for the 75L/70

    ______Bovington´75_____Jentz

    range

    500m 141@30 124@30

    1000m 121@30 111@30

    1500m 104@30 99@30

    2000m 89@30 89@30

    Any ideas ?

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

    [This message has been edited by The DesertFox (edited 08-23-2000).]

  17. Just to complete the picture of 88L/71 APCBC penetration data and to confuse everyone with more data wink.gif. Here are some more.

    First Ian V.Hogg "German Artillery of WW2"

    Projectile weight: 10,4 kg

    Muzzle Velocity: 1000 m/s

    Penetration:

    500m : 207mm@0 , 182mm@30

    1000m : 190mm@0 , 167mm@30

    1500m : 174mm@0 , 174mm@30

    2000m : 159mm@0 , 139mm@30

    and F.M. von Senger und Etterlin "Die Deutschen Panzer 1926-1945"

    Projectile weight: 10,16 kg

    Muzzle Velocity: 1000 m/s

    Penetration:

    0m : 225mm@90 , 198mm@60

    457m : 207mm@90 , 182mm@60

    915m : 19mm@90 , 167mm@60

    1372m : 174mm@90 , 153mm@60

    1829m : 159mm@90 , 139mm@60

    2286m : 145mm@90 , 127mm@60

    If someone is interested to convert the @60 values to @30 values, here´s the table out of Jentz Tiger book:

    "As a standard for comparision the effect at 30 degrees angle of impact is set to 100%. Penetration ability at other angles may be estimated from the following table:"

    Projectile Type Angle of Impact

    PzGr39 (APCBC) 120@0 , 100@30 , 60@45 , 40@60

    PzGr40 (APCR) 120@0 , 100@30 , 60@45 , 30@60

    Gr HL 105@0 , 100@30 , 80@45 , 50@60

    Example: The penetration ability of the 7,5 cm PzGr39 fired from Pak40 at a range of 1000m is 81mm at an angle of impact of 30 degrees. Penetrating ability at this same range a 0 degrees is 95mm, 45degrees is 50mm and 60 degrees is 32mm.

    Ugh, I forgot that there are even more data wink.gif

    Ok here it goes:

    ....and more data:

    Bovington Museum, 1975

    "Fire and Movement", RAC Tank Museum, Bovington, 1975, pages 22–25. "Penetration v. homogenous armour at 30º, at ranges in yards". The armour is machineable quality.

    Weapon Ammo 100 500 1000 1500 2000 2500

    88mm L71 APCBC 182 167 153 139 127

    ....and more

    WO 185/194, Tank and anti-tank armament.

    A table of "important German SP equipments" gives the following figures for penetration of homogenous armour at 30º with APCBC ammunition:

    500 yds 1000 yds

    8.8 cm Pak 43/1 (L/71) 184 169

    ....and more

    WO 219/2806, Appendix G to SHAEF/16652/GCT/Arty

    Dated 11 July 1944. "Perforation of homo at 30º Strike", ranges in yards.

    Weapon Ammo 600 1000 1600 2000

    German 88mm KWK 36 (f) APCBC 108 102 94(a) 87

    KWK 43 (f) APCBC 178 140 131(a) 121

    Notes: (a) Approximate figure (d) Tapered bore (g) A 1945 project

    (B) Fits US 57mm (e) PANTHER gun

    © In production but NOT in service (f) TIGER gun

    ....and some more <G>

    WO 291/1407, "The Characteristics of 13 SP Assault Guns."

    Penetration in millimetres at normal impact at 1000 yards:

    Gun APCBC penetration Special ammo Penetration

    8.8cm L71 200 AP40 222

    Enjoy wink.gif

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

    [This message has been edited by The DesertFox (edited 08-23-2000).]

  18. <BLOCKQUOTE>quote:</font><HR>At this point I need more time to study the results, but several things are clear....the shape and hardness of the ogive has a direct baring on penetration perfromance more so than velocity. The narrower and harder the tip the longer the delay in the onset of the 'transitional velocity'. It seems the this is the division between 'modern erosion' type penetration and 'normal' penetration.

    I can post Jpegs to that site so I'll focuse on working some thing out there<HR></BLOCKQUOTE>

    Yes Paul,

    I talked with Claus Bonnesen about the issue. I´d be interested to see them.

    Helge

  19. <BLOCKQUOTE>quote:</font><HR>Do you have any hard figures for this effect that could account for the

    difference between the German test results and what the Brit equations

    would predict?<HR></BLOCKQUOTE>

    LOL! The test results don´t fit the formula, ergo the test results are wrong ?

    Actually I would see it vice versa. Formulas are a sorry substitute for hard data and this example clearly shows the problems involved when trying to fit the real world hard data into a formula. The non ability to describe a phenomenon with a certain formula not necessaryly means that the phenomenon doesn´t exist.

    Try to do the comparison I did just for fun with David Honners formula with 2 other guns. Or compare the data like Charles did. Try to compare the 75L/24 with the 75L/70 and see how silly the outcome is. Does that mean the data for the 75/L70 are faulty ?

    BTW: If you use the very rough formula at David Honners site you have to use the velocity of the shell in the moment of IMPACT and NOT the muzzle velocity. <G> Velocity drops from the moment the projectile leaves the muzzle, so unless you know the velocity at 100m, 500m, 1000m etc. you cannot use the formula.

    Anyone who has these data ? No this question wasn´t serious wink.gif

    Helge

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    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

  20. <BLOCKQUOTE>quote:</font><HR>willys said: Helge,

    From my understanding of the materials I have read regarding German use of tungsten-cored rounds, production fell off dramatically after about 1941 because of the lack of available wolfram to create these projectiles.<HR></BLOCKQUOTE>

    That isn´t the whole truth. From 1941 the germans shifted more and more tungsten to the production of higher caliber ammo. At first to the production of 5cm PzGr40 and then to the 7,5cm PzGr40 and the 8,8cm. Until in 1943 nearly all production of tungsten cored ammo stopped due to the shortages.

    To the 28mm you mentioned: I guess you are referring to the s.PzB 41, wich was indeed a surprize for the Brits when they discovered that germany was using sqeeze bore guns in 1941 in NA. I don´t know much about it except that some special adaptions were made and it was issued to the Fallschirmjäger and used in greater quantities on the Eastern Front until the whole Panzerbuechsenconcept was skipped when they rendered virtually useless.

    Helge

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    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

  21. Hey cool Charles,

    That sounds reasonable to me. I just did some maths myself with the following formula:

    Og_4_10.gif

    where mp = mass of projectile (kg);

    V = velocity of the projectile at impact (m/s);

    t = thickness of armour perforated (mm);

    d = diameter of projectile (mm); and

    C, n = constants.

    I choose the advanced formula for APCBC:

    Og_4_12.gif

    and the result I optained was that in case of the 75mm APCBC (6,8kg) and increase of the velocity of 25% is leading to an increase of armor penetration of 36%.

    In case of the 88mm APCBC (10kg) an increase of the velocity of 29% (773ms-1000ms) is leading to an increase of armour penetration of 40%.

    That tells me that indeed the data presented by Jentz for the 88/L71 does not seem to follow this AFAIK commonly accepted rough formula presented above. Maybe the germans used RHA plates of different quality for the tests.

    But I have to second Johns statement that there definitively are no carved in stone penetration figures. Each country did different tests with different parameters that makes it hard to compare them. You have to look at them more as to an approximation and to keep sceptical if something doesn´t fit the whole picture. There is no black and white, more various shades of grey. wink.gif

    The only problem I see here with accepting penetration data which base on PRIMARY material (german tests in this case) and in an other case not accepting PRIMARY material out of the same source (we have to keep in mind that it isn´t Jentz who cranks them out. He is quoting them from primary sources) is calling into question the whole lot of data which went into the game. Who draws the line (BTS of course), and can we call the data in the game realistic ? The answer is NO, but we can call the data a reasonable approximation which is close enough to published sources to give a relistic feeling to the user. It´s a game after all and no realism simulator, and as long as there don´t creep up real flaws it´s fine for me.

    BTW: to anyone who does not already know, David Honner has done a wonderful job presenting tons of penetration data and background information on his website. Pay him a visit at http://www.wargamer.org/GvA/

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

    [This message has been edited by The DesertFox (edited 08-22-2000).]

    [This message has been edited by The DesertFox (edited 08-22-2000).]

  22. <BLOCKQUOTE>quote:</font><HR>Is it that 88/L71’s values are somewhat exaggerated in Jentz’s book and BTS has hit the bullseye in CM with their physics models. Or is it possible that a little correction is needed in CM?<HR></BLOCKQUOTE>

    Naaa,

    Jentz´s values aren´t exaggerated. Actually the data he presents is basing on german tests conducted with target material laid back at an angle of 30 degrees, consisting of rolled homogenous plates with the following hardness dates : 81-120mm (thickness)= 279-309 BNH and 121-150mm = 235-265 BNH.

    If there are correct data around somewhere, these data are. Furthermore you have to keep in mind that due to the fact that the PzGr 39 carried a high explosive charge with delay fuze (the filler) it was of annihilating effect to the crew inside the tank.

    Because of this filler it was sufficient to optain a partial penetration and the explosive charge could complete the destuction of the crew.

    In contrast the effect of the PzGr 40 (tungsten core) was basing solely on whatever kinetik energy remained in shot fragments when it shattered and/or fragments of armor plate broke off after the hit.

    However 1944/45 distribution of 7,5cmL/70; 8,8cmL/56 and 8,8cmL/70 PzGr 40 was VERY VERY VERY rare if at all (that´s a point of discussion even under historians and not absolutely clear).

    To the values in CM: I´m sure Charles can answer why they differ from published sources. However in CM it makes no difference to gameplay AFAIK, so IMHO it may be not a big issue for BTS.

    If you like Jentz "Tiger Combat" book, you will love his Panther book and his book on Armoured Warfare in Northafrica. You wont be dissapointed.

    Helge

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

    Sbelling chequed wyth MICROSOFT SPELLCHECKER - vorgs grate!

    - The DesertFox -

    Email: desertfox1891@hotmail.com

    WWW: http://www.geocities.com/desertfox1891

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