tag:blogger.com,1999:blog-5030145265861917845.post5891059305132611680..comments2024-03-28T14:35:30.147-04:00Comments on Tank Archives: E-50 and E-75: A Story of Failed UnificationPeterhttp://www.blogger.com/profile/09622237223229485503noreply@blogger.comBlogger38125tag:blogger.com,1999:blog-5030145265861917845.post-88616722207708871722017-06-13T09:39:58.192-04:002017-06-13T09:39:58.192-04:00The turret wasn´t decided yet. I´d agree as placeh...The turret wasn´t decided yet. I´d agree as placeholder. Considering that the new suspension offered more internal space, it´s likely they wanted to use the space as they opted not to make the hull smaller.<br /><br />Panther Ausf. F and Ausf. G would receive Schmalturm turret in mid 1945, with proposals to update to 88mm KWK 43.<br />Claims from this article that the " the commander would have to sit on top of the gun breech" are not correct.critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-43900470923322440792017-05-18T12:53:13.629-04:002017-05-18T12:53:13.629-04:00On a sidenote, can we just take a second to apprec...On a sidenote, can we just take a second to appreciate how sexy the Panther II's suspension looks?Blockio1999https://www.blogger.com/profile/09950176206287081383noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-63909106387534309982017-05-18T10:40:42.495-04:002017-05-18T10:40:42.495-04:00Placeholder, probably, seeing as how no data about...Placeholder, probably, seeing as how no data about the turret (aside from the bore axis height) is given.Peterhttps://www.blogger.com/profile/09622237223229485503noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-13374826222103667742017-05-18T10:31:45.442-04:002017-05-18T10:31:45.442-04:00I'm a little late, but what about this drawing...I'm a little late, but what about this drawing waretmarked by Doyle showing a Panther turret on a E-50/75 hull? Just for reference?<br /><br />http://3.bp.blogspot.com/-54--cDIow-g/T9cgsSSUycI/AAAAAAAAA_U/X0vlvJbIM1E/s1600/E50&70+sketch+a.jpgAnonymoushttps://www.blogger.com/profile/15777228221346025475noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-12186863719213604172017-05-11T02:08:31.565-04:002017-05-11T02:08:31.565-04:00It seems that side thicknesses given here are not ...It seems that side thicknesses given here are not from 1st prototype but from a later. critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-5229827486423491832017-05-05T12:02:10.588-04:002017-05-05T12:02:10.588-04:00Critical mass
perhaps you can also post at...
ht...Critical mass<br /><br />perhaps you can also post at...<br /><br />https://forum.axishistory.com/viewforum.php?f=47<br /><br />It would be great to have you discuss technical issues, thanks.Yugonamehttps://www.blogger.com/profile/09363049276280844713noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-20748136523798312912017-05-04T02:28:44.993-04:002017-05-04T02:28:44.993-04:00I am not sure what fuzes have to do with it. Krupp...I am not sure what fuzes have to do with it. Krupp developed a grace function of the fuze for very high obliquity but it required sheath hardened walls (only some lots of 10.5cm and 12.8cm had those). A stop gap was to harden the threaded grips of the fuze container in decrementally hardened AP. <br /><br />The problem with high obliquity is that mechanics of plate and projectile failure change rapidly. <br /><br />When I come across prooving ground results for high obliquity trials, such as carried out 1942-1944 in BA/MA RH 8/- files, a penetration was counted as "Durchschlag" only if either the whole projectile or fragments up to the forward bourrolet were found behind the plate at 60° and 75°. To identify the original 1890´s defintions of "Durchschlag" would take a couple of weeks in Freiburg, and I am not going to do this, for me it´s sufficient to know how it was done. It is essentially the correct approach because highly oblique impact vs relatively thin (<cal/plate ratio), ductile plate will result in a base first penetration, unless high hardness armor causes sufficient normalization to allow a nose first event (when associated with a lower strain rate in the plate -indicated by adiabatic shear failure rather than ductile slot formation-, this will cause a very substantial reduction of ballistic protection). Base first penetration will, of course mean that fragments of the base will be more commonly encountered behind the plate than fragments of the nose.critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-37398986787608261632017-05-03T15:20:52.111-04:002017-05-03T15:20:52.111-04:00So you are saying the criteria for a broken up she...So you are saying the criteria for a broken up shell is not in that report. And what about the definition “...should result in fragments of the projectile up to and incl. the fwd bourrolet...”? Where does that come from?<br /><br />“The Germans admitted quite definitely that they realized that their fuzes were by no means perfect and some went so far as to say they were bad; but they thought that if the shell broke up the critical velocity for penetration would be higher and that a shell entering an armoured vehicle, even if whole, would be lethal.” German Steel Armour Piercing Projectiles and Theory of Penetration report for B.I.O.S. Mobiushttps://www.blogger.com/profile/05256982406940327658noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-87131095111316757832017-05-03T11:10:54.119-04:002017-05-03T11:10:54.119-04:00the criteria isn´t described therein, Sitz points ...the criteria isn´t described therein, Sitz points out the fact that all projectiles will break up at obliquities larger than 45° (p.112: "..., bei 45° dürfte ein Heilbleiben auch möglich sein und muß angestrebt werden, bei flacheren Winkeln werden die Geschosse zerbrechen.") <br />The "G_D" criterium in use for official penetration curves dates back to the late 1890´s. It wasn´t extra discussed in ww2 as something new. There were three curves used:<br /><br />A) "Grenzkurve" - the velocity at which the projectile depletes all energy and either <br />A1- projectile remians intact but is stuck in plate (not through)<br />A2- projectile completely penetrates but in a broken condition<br /><br />B) "Durchschlagskurve" defines thee vlocity at which the projectile always completely penetrates (base completely through). The projectile may be broken up or stay intact (similar to A2 but A1 would never be considered "Durchschlag", slight difference) <br /><br />C) "Heilbleibkurve" defines the velocity at which the projectile always penetrates in a condition fit to burst (no damage allowed).<br /><br />B) was used by the Army, A) and C) by the navy (for homogenious Wh armor, the curves of A- and C fell together for the latest projectiles creating but not for KC). Only for acceptance of armor piercing ammunition, the Army criterium specified at the proofing angle (30°, later increased to 45°) that the projectile has to stay intact (Navy "heilbleib" criterium). For explorative trials to investigate penetration performances, the Army was using the older "Durchschlag" criterium, which is understandable because intact penetration was not obtainable for cal/plate(Krupp trial quality) ratios larger than ~0.8 (for Pzgr39) at 60°. And even if the projectile stayed intact, it cannot be expected do so for five consecutive attempts without failure occuring. In such shots, the limit of the plate is generally taken at that velocity, which insures perforation and the passage of the projectile, whole or in pieces, through the plate in agreement with the requirement for G_Durchschlag. This limit is higher than the theoretical one under conditions, where the projectile does not stay intact because of the energy consumed in the process of projectile break up but it was the only practicable way to secure comparative figures without deviating from the 5/5 requirements.critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-25982126940012376322017-05-03T09:35:25.689-04:002017-05-03T09:35:25.689-04:00What page in Lilienthal-Gesellschaft 166 (1943) de...What page in Lilienthal-Gesellschaft 166 (1943) describes the +40̊ shell break up penetration criteria?Mobiushttps://www.blogger.com/profile/05256982406940327658noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-81348856748775280262017-05-03T07:01:57.539-04:002017-05-03T07:01:57.539-04:00During these trials, they also compared their dome...During these trials, they also compared their domestic 90mm M82 fired from an experimental, high velocity 90mm gun with the german 88mm Pzgr39 fired from PAK43**. Against 8" RHA plate, and normal obliquity, the 90mm M82 always broke up and didn´t managed to obtain a calibre sized hole through (just bulge) at 950.9m/s and 986m/s velocity.<br />The 88mm Pzgr39 was stuck in the 8" plate at 914.7m/s (partial penetration, intact with nose through) and penetrated completely at 952.2m/s and 992.7m/s -without any damage. <br /><br />The turret of the improved, T54 obr.1951 was also tested ballistically at the NIIBT vs 90mm M82 at the soviet prooving ground (MV:930m/s), aiming for the horizontal perpendicular of the turret casting. A total of 28 hulls and turrets was tested (large sample). The limit of PKP (plugs and discs started on the backside) vs the 90mm M82 projectile was 900m -1400m, depending on the turret (large variance in quality of the armor castings, particularely against 100mm projectiles (600m - 2200m limit of PKP) indicate the presence of both, ductile and brittle turret castings). Considering that the M82 again broke up -as did all 100mm- and also was fired at lower initial velocity, it´s fairly certain to presume that the limit of penetration for the 88mm would be at substantially longer range than that obtained by the 90mm M82. This entailes also a higher probabiliyt of a limit of perforation (not obtained by either domestic soviet 100mm or US 90mm M82 projectiles). <br /><br /><br />---<br />** in my own opinion, the lot of Pzgr39 the US Army used to test at Aberdeen -unlike the 75mm Pzgr39 lot- was on the very low end of quality range variances. This is indicated by the poor performance vs 5" RHA @45° - with most projectiles shattering -unlike the 75mmPzgr39, which was better here than the 88mm Pzgr39. Such poor performing 88mm projectiles would not have been accepted for service after mid 1944 when the proof obliquity was changed from 30° to 45°.critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-73796134833885001002017-05-03T03:20:45.167-04:002017-05-03T03:20:45.167-04:00I am sure the british had their own tests and shar...I am sure the british had their own tests and shared them with the US but the US also conducted it´s own series of trials. For the matter in quetion, I am referring to trials conducted on feb. 6th & 7th 1945 at the Aberdeen Army prooving ground using US RHA plate made by Carnegie-Illinois (plate # TT-281 1/4). The gun was the 75mm L/70 KWK42 mounted on a captured Pz V. Project No. 5065 (574-P12-114). I have read the complete report.critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-70568082944620021892017-05-02T15:51:47.428-04:002017-05-02T15:51:47.428-04:00"At the USPG, the projectile was successful&q..."At the USPG, the projectile was successful" I'm not aware of a US 75mm/L70 PzGr 39 test. US data all seem to come from British tests.<br /><br />BTW, what is the MV of the 75mm Pak 40. Germans have it at 750 m/s and Russians at 770 m/s.<br />Mobiushttps://www.blogger.com/profile/05256982406940327658noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-20677113052439202952017-05-02T14:44:48.334-04:002017-05-02T14:44:48.334-04:00J. Sitz comments on practical experiences of the p...J. Sitz comments on practical experiences of the prooving ground work in Lilienthalreport 166(1943) and Hillersleben minutes (1944).<br />The german anti tank projectiles were designed such that the velocity for penetration and the velocity for intact penetration fall together (extreme case: Projectile stuck in plate or even rebound in intact condition with no damage other than stripping of driving bands and nose covers). <br />At obliquities of 40° and above, the variance and the delta between fragmented perforation and intact penetration increased. Also, the type of plate failure enlarged (ductile [slot formation] failure, adiabatic shear failure causing plugs or discs).<br /><br />Notice that they still required a 5 out of 5 success criterium, which is difficult to obtain when break up occurs once in a while.<br /><br />f.e. German official penetration curves give 95mm RHA @ 45° for the 75mm Pzgr 39 at ~960m/s.<br />At the USPG, the projectile was succesful, sometimes at least, against 132mm RHA plate and stayed intact. <br />132mm from US tests is much thicker than 95mm from german official penetration curves, don´t You think? <br /><br />critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-28437518064080981132017-05-02T12:00:24.115-04:002017-05-02T12:00:24.115-04:00“Past 45̊,when breakage sets in, the definition wa...“Past 45̊,when breakage sets in, the definition was that five out of five tests should result in fragments of the projectile up to and incl. the fwd bourrolet were to be recovered behind the plate.”<br />What is your source for this? It would infer there are two different standards for the same shell. The penetration graph would not be smooth at the transition angle but would have a shelf there.Mobiushttps://www.blogger.com/profile/05256982406940327658noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-10963772594063580272017-05-02T08:04:18.817-04:002017-05-02T08:04:18.817-04:00Mobius,
the V/50 penetration criterium is a confo...Mobius,<br /><br />the V/50 penetration criterium is a conformal definition for cross-country comparison. However, I am sure You are aware that the german penetration curves are not Krupp curves. Both Krupp and Rheinmetall had their own penetration curves, seperate form the official ones and based upon the company´s historical samples.<br />While these are primary sources, they are company internal sources and therefore are less reliable than, say WaPrüf´s official penetration curves, tested for on the gouvernmental (speak: independent) prooving ground, not on the company´s one. I have leaked a set of these official penetration curves from my archive to You (and others) a couple of years ago and You´ve used it under Your own term "Datenblatt" since.<br />These are "Durchschlag" curves, in which five out of five tests (no failure allowed) within a narrow velocity range have to completely penetrate a plate of known tensile strength in intact condition (up to ca. 40°) with the failure mode of the plate beeing ductile hole formation.<br />Past 45°,when breakage sets in, the definition was that five out of five tests should result in fragments of the projectile up to and incl. the fwd bourrolet were to be recovered behind the plate. The failure mode of the plate under these conditions was dominated by plugging.<br /><br />The official german "Durchschlag" definition is way more severe than the conformal V/50 and represent a close to 2sigma confidence criterium.<br /><br />Whenever armor penetration is concerned, it´s not enough to know the velocity, obliquity and tensile strength of the plate but also the be able to identify the specific failure mode under which the plate gave way to -or resisted a penetration. <br />That´s why I use to consider only tests, where information of the projectile damage and plate damage is included.<br />This kind of information is not available in the Yugo tests, and this can and will lead people not familar with penetration mechanics to misleading conclusions.critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-7729047316606816462017-05-01T18:49:44.165-04:002017-05-01T18:49:44.165-04:00Obviously "heat" was the reason, as ever...Obviously "heat" was the reason, as everyone knows how concerned Adolf was with the fate of the planet, and being an advanced being, he foresaw the advent of global warming. <br />So such machines were not at all allowable per his world plan.<br /><br />I mean, just look at his regimes work toward alternative fuels, and population control. Meplathttps://www.blogger.com/profile/12480254610764041359noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-25459210371536546572017-05-01T17:44:43.524-04:002017-05-01T17:44:43.524-04:00Surely you already know that critical mass conside...Surely you already know that critical mass considers his own opinion more reliable than tests performed by contemporary experts.Peterhttps://www.blogger.com/profile/09622237223229485503noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-9450541794349430042017-05-01T17:34:28.528-04:002017-05-01T17:34:28.528-04:00Actually, not enough has been made of the Yugo tes...Actually, not enough has been made of the Yugo tests. They use the v50 penetration criteria rather than the inconsistent Krupp criteria.Mobiushttps://www.blogger.com/profile/05256982406940327658noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-47405978977057512642017-05-01T16:21:59.436-04:002017-05-01T16:21:59.436-04:00True enough. I was considering, in agreement with ...True enough. I was considering, in agreement with high number of penetrations in the turret sides- that the turret doesn´t necesarely need to be pointing where the hull points to. Purely frontally, I agree, the sides will be immune due to acute angular exposure.critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-43553996136535824962017-05-01T16:16:11.890-04:002017-05-01T16:16:11.890-04:00It´s not a theory, Mobius, it´s empirically proove...It´s not a theory, Mobius, it´s empirically prooven. Too much is made of the Yugo test. <br /><br />1st) according to german penetration charts, the 88mm PAK43 can´t be expected to penetrate more than 80mm-90mm RHA @ 60° and 1000m/s. The failure mode in these tests was ductile failure, the projectile always breaks up. <br /><br />2nd) well, the same gun did penetrate 90-100mm high hardness soviet cast armor @60° in soviet tests at down to 920m/s, and 90mm high hardness RHA at significantly less from soviet tests.<br /><br />3rd) it didn´t penetrate the T54 glacis AS COULD BE EXPECTED. The T54 manufacture shifted towards a more ductile armor material in the early 1950´s, which had 8%-11% less protection at 30° but ~10% better protection at 60°.<br /><br />4th) it did penetrate the M47 glacis. This could NOT be expected but is possible considering the problems the US had with 3" and 4" armor ingots for RHA plate. It´s very likely the plate failed by adeabatic shear or brittle failure. Notice the plate was soft, but this doesn´t necessarely mean it was also ductile. <br /><br /><br />So either soviet cast and RHA were >20% inferior to german RHA (possible only for cast armor but not for RHA), or alternatively, the penetration was effected by shear failure, a low energy penetration, for which we have indications from the tests.<br />The T54 glacis didn´t behaved "special", just exactly as could be expected from a Krupp trial plate.<br /><br />Notice, while there is a correlation between tensile trength and strain rate, it´s not an absolute autocorrelation and depends a lot on armor steel mix, section thickness, quenching temperature, cooling rate, re-tempering range and post tempering cooling.<br />Soft armor steel needs to be quenched from fairly high temperature, and if cooling rates are slow enough- or the section thickness large enough to cause slow internal cooling rates- than even soft armor becomes brittle.critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-30137357674872099152017-05-01T15:56:50.013-04:002017-05-01T15:56:50.013-04:00Mobius,
I referenced 30° and 0°. Not 55°. I guess ...Mobius,<br />I referenced 30° and 0°. Not 55°. I guess You are familar with the differences. 55° results in base first penetration (only possible in mild steel and VERY SOFT armor) -otherwise the projectile always brakes up (You can´t harden the base or the filler will touch off causing prematures). It´s larger than the obliquity under which the projectile can be expected to stay intact.<br />If You have the report, try looking for the entries for 0° and 30° obliquities, and compare US and german shell for details.<br /><br />In general, let me quote the conclusions:<br /><br /><br />"RESULTS.<br />A. That the german projectiles had better penetration charackteristics against homogenious armor plate than the American projectiles.<br /><br />B. That the german had less tendency to shatter when fired against homogenious armor plate at high velocities<br /><br />RECOMMANDATIONS.<br />It is recommended that the design features, hardness pattern and composition of the German armor piercing projectiles be studied for purpose of improving American armor piercing ammunition."<br />critical masshttps://www.blogger.com/profile/02366274198749901618noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-16993619454972262882017-05-01T09:56:53.845-04:002017-05-01T09:56:53.845-04:00If you’re talking about the US high velocity tests...If you’re talking about the US high velocity tests of German 88mm Pzgr39/43 results vs. high angle armor were:<br /><br />3 7/16" (87mm) @ 55̊° Two complete penetrations. both projectiles fractured. Projectile fragments passing through plate. One partial penetration projectile fractured. 1016 m/s MV on two penetrations. 1009 m/s MV on 2.5" deep partial. Mobiushttps://www.blogger.com/profile/05256982406940327658noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-91930049708188937812017-05-01T09:33:22.054-04:002017-05-01T09:33:22.054-04:00Critical Mass
“ Ricochet would be more common with...Critical Mass<br />“ Ricochet would be more common with less hard, more ductile plates..”<br />Makes an interesting theory but in practice not so much. In the Yugoslav tests of the 50s and 60s the softer 102mm@60̊ armor of the M47 could be penetrated by the 88mm PaK43 at 250 meters. While the harder 100mm@60̊ armor of the T-54 could not do so at any range.Mobiushttps://www.blogger.com/profile/05256982406940327658noreply@blogger.comtag:blogger.com,1999:blog-5030145265861917845.post-69498591933248242682017-05-01T07:17:12.946-04:002017-05-01T07:17:12.946-04:00Are you considering that the turret side is only p...Are you considering that the turret side is only presented at an extreme angle from the front? It is already 150mm thick and is presented at greater than 60 degrees from perpendicular.<br />In addition, even if we assume the bottom half of the turret is a shot trap, the top half isn't.li07.jasonhttps://www.blogger.com/profile/02615594101085179532noreply@blogger.com