Path: spln!rex!dex!extra.newsguy.com!lotsanews.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!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: Tue Oct 30 23:33:39 2001 Delivery-Date: Tue, 30 Oct 2001 23:33:39 -0800 for <sci-military-moderated@retro.com>; Tue, 30 Oct 2001 23:33:38 -0800 (PST) id QQlnbx05922 for <sci-military-moderated@moderators.isc.org>; Wed, 31 Oct 2001 07:17:26 GMT for <sci-military-moderated@moderators.isc.org>; Tue, 30 Oct 2001 23:17:25 -0800 for <sci-military-moderated@moderators.isc.org>; Tue, 30 Oct 2001 23:17:25 -0800 for sci-military-moderated@moderators.isc.org; Tue, 30 Oct 2001 23:17:25 -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: 30 Oct 2001 23:17:25 -0800 Organization: http://groups.google.com/ Message-ID: <de5bf54f.0110302317.5a05e7db@posting.google.com> References: <i3qB7.152293$5A3.52800604@news1.rdc2.pa.home.com> <a516ee75.0110252036.230ea683@posting.google.com> <5dcb47db.0110260556.1019019@posting.google.com> <de5bf54f.0110261517.55877d2d@posting.google.com> <Xns914770EF9841BaldHeadedJohn@62.172.195.196> <de5bf54f.0110271532.871cbf@posting.google.com> <Xns91486A379CD8FBaldHeadedJohn@62.172.195.196> X-NNTP-Posting-Host: 207.23.94.167 Content-type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Complaints-To: groups-abuse@google.com X-NNTP-Posting-Date: 31 Oct 2001 07:17:25 GMT Content-Length: 3142 Lines: 61 NNTP-Posting-Host: f0db9685.newsreader.tycho.net X-Trace: 1004549481 gemini.tycho.net 436 205.179.181.194 X-Complaints-To: abuse@tycho.net Xref: spln sci.military.moderated:39967 John D Salt <john.salt@NOSPAM.btclick.com> wrote in message news:<Xns91486A379CD8FBaldHeadedJohn@62.172.195.196>... > psl@interchange.ubc.ca (Paul Lakowski) wrote in > news:de5bf54f.0110271532.871cbf@posting.google.com: > [Snips] > > "Journal of Battlefield Technology" Vol 1-1 pp 1 a article > > was published on HEAT developement and standoff > > penetration chart was published for Steel,Copper and > > Aluminum cone shaped liners.. > [Chart snipped] > > Thanks for that: A cut-out-and-keep table if ever I saw one. > > Now this is where I get in well over my head on warhead and > armour design, but I would guess that most WW2 HEAT rounds would > use copper liners. I would further guess that 340 Brinell would > be pretty close to the right hardness for German 30mm MQ plate in > 1943 (on the strength of PRO document WO 185/118, DDG/FV(D) > Armour plate experiments, if anyone cares). > > So the relevant line would be: > > Liner ------ 1.0 2.0 3.0 4.0 5.0 6.0 > > Copper | --- 4.2 4.4 4.2 3.8 3.4 2.8 Vs 340BHN > > ...which means that an additional standoff of half-a-dozen > calibres would have considerable benefits in protecting the main > armour. Against the sort of HEAT weapon I'm thinking of, a 76mm > gun or 66mm Bazooka, that means a couple of feet. How far are > Schurzen typically hung from the main armour? Actually John; Bazzooka and Pzfaust and PzSchreck warheads where iron liner as where most german gun fired heat. Not sure about russians but I think copper was too valuable to waste on warhead designs. Pzfaust had ~ 0.4-0.6 Cd standoff while Bazooka was 2 Cd standoff so the figures are about 3 Cd & 2.5Cd Vs mild steel which according to Ogorkiewic HEAT penetration of mild steel [ ~ 100 BHN] should result in a difference of ~ 2/3 so 3 Cds becomes 2Cd penetration for bazooka into RHA . Which would be 5 inches of penetration , close to whats quoted. Pz faust should do 2/3 of 2.4-2.6 or 1.6- 1.7 x 150mm = 240-250mm which exceeds the quoted penetration by 25-40mm . It could be a spin on the warhead or the liner cone is not at as sharp an angle. But in a test of scaled Bazooka warheads in 1948 penetration at standoff was tested and the increase in standoff that a Pz-IV side skirts should offer ~66cm or ~ 10 cone diameters additional standoff . By standoff alone the penetration drops to ~ 1.3 Cd penetration into RHA or ~ 3.5 inches. More than enough to penetrate the 30mm side hull. The 10mm mild steel plate should offer 2x 10mm x 0.67 = 13mm bringing this down to 77mm penetration. Still more than a match for 30mm side hull, even from 45° strike angle the standoff curve is about the same [~ 3.4 inches of penetration ]while the plate resistance is up to 4 x 10mm x 0.67 @ 45° [÷ COS 0.7] = 38mm . Thus the penetration should be ~48mm or ~34mm @ 45°...just enough to penetrate. But note that the same side skirts struck by a PzFaust warhead has the opposite effect. The standoff goes from 0.4-0.6 up to 4.4 Cd standoff [ 660mm ÷ 150mm warhead], and the penetration goes up by ~40% [roughly 1.6Cd to 2.3 Cd ], not down as in the case of the Bazooka.