John Kettler Posted March 3, 2006 Share Posted March 3, 2006 Came across some of your impressive TO&E and gun performance stuff while trying to help Locksley with the 6 pdr data search. Links were too long to list, and the cut and paste doesn't work for some reason with the URL button. Request you a) post a list of your online pubs with a view to having same stickied or otherwise permanently readily available. Regards, John Kettler 0 Quote Link to comment Share on other sites More sharing options...
Michael Emrys Posted March 3, 2006 Share Posted March 3, 2006 Good idea! Michael 0 Quote Link to comment Share on other sites More sharing options...
John D Salt Posted March 6, 2006 Share Posted March 6, 2006 Originally posted by John Kettler: Came across some of your impressive TO&E and gun performance stuff while trying to help Locksley with the 6 pdr data search. Links were too long to list, and the cut and paste doesn't work for some reason with the URL button. Request you a) post a list of your online pubs with a view to having same stickied or otherwise permanently readily available. That should be nice and easy. As far as I am aware, there is currently no site hosting this information, and certainly none hosting the current version. Chris Wilson very kindly put the stuff up at his "Britwar" site, but that seems to have evaporated. Since my ISP provides a few megs of freebie web space, producing a web page of my own has been on my "things to do" list for a number of years now. It looks as if it may remain there for a few years more. The penetration file has been completely reorganised over the past couple of years, and is now organised by weapon within category within nationality, instead of as previously by alphabetical order of source (probably the stupidest way to arrange such a file I could have come up with). It has also had a diatribe on ammunition natures and other such stuff added, including my unpopular opinions on Schurzen, and all quantities (in particular, ranges) are now in SI units. During the course of this re-working, I have attempted to track all those places where the sources duplicate each other. As a result of this, I have concluded that, of the 234 sources consulted, you probably need only the four best ones to get a very good picture of German, US and British weapons' penetration performance. For the Russians, I have still found nothing in print as good as Valera Potapov's Russian Batlefield site, which we all know and love. Although I will continue to add new sources as they become available, I have pretty much lost interest in collecting penetration data. The reason for this is that practically no source gives all the information one requires to make sense of the figures provided; in particular, it is very rare to see them give the hardness of the target plate and the penetration criterion used. I started trying to collect penetration formulae, on the grounds that these let you (as Rexford pointed out years ago, and CM has done since its inception) work out the performance of different nationalities' weapons irrespective of their proof criteria. To my surprise and disappointemnt, I could find very few believeable and useable formulae, and fewer still that represented any improvement on de Marre -- you'd think there would be more progress in over a century. My firm favourite to date is Dehn's formula from Technical Report BRL-TR-2770, "A Unified Theory of Penetration", James T. Dehn, December 1986. In the form I have used it, this deals with non-eroding projectiles striking semi-infintite targets at normal impact, ignoring friction. I have written a Java program (I now think I should have stuck to Python) to use the formula, and it gives what I consider believable results. I have yet to get my head around the extended versions of the formula which allow for projectiles losing mass (eroding as they penetrate the target) and gaining mass (during the formation of an explosively-formed penetrator), and it is not obvious to me how I can adapt the formula to account for striking angle, nose shape, the effect of ballistic caps, brittle failure of high-hardness armour steels, projectile shatter, and multiple or non-homogenous plates. Being neither a physicist nor a mechanical engineer I have struggled somewhat to get to grips with the elementary concepts involved, so if anyone can give me a good clear explanation of how adiabatic shear stress banding works I would be very grateful. Even if I ever do work out how to extend the formula to account for the factors above, the problem remains of finding believable figures for the density and ultimate tensile strength of WW2 armour and projectile steels. At the moment I am assuming a constant density and estimating the strength from the Brinell hardness. Anyone not discouraged by these maunderings who still would like a copy of the latest edition of the penetration file, please e-mail me at the address shown in my profile, with "WW2 penfile" in the message title. All the best, John. 0 Quote Link to comment Share on other sites More sharing options...
WineCape Posted March 8, 2006 Share Posted March 8, 2006 Originally posted by John D Salt: ....if anyone can give me a good clear explanation of how adiabatic shear stress banding works I would be very grateful.Send me an e-mail (in profile) and I'll see what I can do to clarify it for you. Sincerely, Charl Theron 0 Quote Link to comment Share on other sites More sharing options...
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