Path: spln!rex!dex!extra.newsguy.com!lotsanews.com!nntp1.phx1.gblx.net!nntp.gblx.net!nntp.gblx.net!newsfeed.direct.ca!look.ca!news.maxwell.syr.edu!news-out.visi.com!hermes.visi.com!gemini.tycho.net.POSTED!not-for-mail Approved: sci-military-moderated@retro.com Return-Path: news@google.com Delivery-Date: Sun Oct 28 15:06:11 2001 Delivery-Date: Sun, 28 Oct 2001 15:03:36 -0800 for <sci-military-moderated@retro.com>; Sun, 28 Oct 2001 15:02:19 -0800 (PST) for <sci-military-moderated@moderators.isc.org>; Sun, 28 Oct 2001 22:46:09 GMT (envelope-from news@google.com) for <sci-military-moderated@moderators.isc.org>; Sun, 28 Oct 2001 14:46:03 -0800 for <sci-military-moderated@moderators.isc.org>; Sun, 28 Oct 2001 14:46:02 -0800 for sci-military-moderated@moderators.isc.org; Sun, 28 Oct 2001 14:46:02 -0800 To: sci-military-moderated@moderators.isc.org From: psl@interchange.ubc.ca (Paul Lakowski) Newsgroups: sci.military.moderated Subject: Re: WWII Armor types Date: 28 Oct 2001 14:46:01 -0800 Organization: http://groups.google.com/ Message-ID: <de5bf54f.0110281446.2c24b883@posting.google.com> References: <5dcb47db.0110260556.1019019@posting.google.com> <9rej52$7c8$1@thorium.cix.co.uk> <5dcb47db.0110271754.5bd4c309@posting.google.com> X-NNTP-Posting-Host: 207.23.94.62 Content-type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Complaints-To: groups-abuse@google.com X-NNTP-Posting-Date: 28 Oct 2001 22:46:02 GMT Content-Length: 3628 Lines: 79 NNTP-Posting-Host: 6a470b8f.newsreader.tycho.net X-Trace: 1004407033 gemini.tycho.net 441 205.179.181.194 X-Complaints-To: abuse@tycho.net Xref: spln sci.military.moderated:39919 cray74@hotmail.com (Mike Miller) wrote in message news:<5dcb47db.0110271754.5bd4c309@posting.google.com>... > OTOH, I could probably argue the Schurtzen would be a weight- > efficient way to fragment and induce a tumble in a 14.5mm AP > round. > > So I can form my conclusion(s), but I wouldn't trust them. > > Mike Miller, Materials Engineer Well thats the whole point of the sheilds.There as mass efficent as the equivelent in armor but its the post impact tumble rates and decapping of APCBC ammo .Dr Elders paper showed that ~0.15d plate was all thats needed to decap so 5-10mm plate would effectively decap projectiles up to 33-67mm diameter, so it should still be effective against 75mm shells. BTW if anyones interested I can Email his paper to them.<psl@interchange.ubc.ca> Here are some sample effects of yawed penetrators that doesn't include the damage effects of the plates directly. The results are as follows Yawed impact of Steel Ogive AP shot [ 4:1 L/d ] at sub ordnance penetration velocity produced Yaw as follows from tests. Int. J . Impact Engng Vol 22- (1999) REVIEW Non Ideal Projectile Impact on Targets ,pp 100-381 [pp212]. AP @ 800-900m/s °YAW = % loss of pen 2° = 1% loss 4° = 2-3% loss 6° = 3-4% loss 8° = 4-6% loss 10° = 5-7% loss 20° = 10-14% loss 30° = 15-21% loss 40° = 20-28% loss 50° = 25-35% loss The immediate post impact yaw of AP shot through thin mild steel plates is ~ 4-12°,if these projectiles are given enough space to tumble they could easly strike the main armor yawed at 60° or more.Int.J.Impact engng Vol-19, pp395-414. Tests on finite thickness of various metals struck by APM2 -7.62mm AP shots [Rc 62 hard steel core] struck thin steel plates [ T/d 0.4] @ 850m/s resulted in the penetrators shattered atleast into halfs every time.Int.J.Impact engng Vol-25 pp423-437. Tests on mild steel chains immersed in epoxy resin , struck by 0.30 & 0.50 AP shots [T/d ~ 1:1 ; chain fractional volume 0.2 ], showed the thickness effectiveness of the panels ~ the similar to mild steel plate in resistance [ 50% to 100% of mild steel 80 BHN].These studies didn't look at impact on follow on plates so don't take into account yawing etc.The average resistance should have been 0.24 Te but ended up ranging from 0.21 to 0.42 Te.The movement of the chains in relation to the penetrator , while being struck was credited with this effectiveness. Looking at the anti heat theory the previously mentioned standoff penetration figures for steel liner shaped charges [ WW-II HEAT] suggest that since the PZfausts warhead standoff was only 0.4 to 0.6 cone diameters stand off.Which means that any amount of spaced plate should have increased the penetration substitally . These 'Schnerzen' plates offered standoff distance of about 66cm {Pz tracks #4} which is 4.4 cone diameters for a Pzfaust. At these standoffs the penetration should up 35-50% and not down at all. The standoff on a bazzooka is ~ 2 cone diameters [J of Applied Phys 1948 Vol 19, pp575]and the penetration should be ~ 2 cone diameters penetration and any increase should reduce this penetration to 1.3 cone diameters @ 9:1 standoff ~ 51cm which is still a penetration of > 3.5 inches RHA. Still more than enough to penetrate the side armor of just about any tank in WW-II. BTW I thought Speilberger reported no damage to the side hull plates in the tests...." Firing tests utilizing the russian 14.5mm anti tank rifle at a distance of 100m [ 90°] showed no tears or penetrations of the 30mm side armor, when protected either by plates or wire mesh."