X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 15 Jul 2007 20:28:47 -0400 Message-ID: X-Original-Return-Path: Received: from global.delionsden.com ([66.150.29.112] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTPS id 2178214 for lml@lancaironline.net; Sun, 15 Jul 2007 00:47:21 -0400 Received-SPF: none receiver=logan.com; client-ip=66.150.29.112; envelope-from=n103md@yahoo.com Received: from bmackey by global.delionsden.com with local (Exim 4.62) (envelope-from ) id 1I9w0D-0005Xp-8Y for lml@lancaironline.net; Sun, 15 Jul 2007 00:46:37 -0400 Received: from 69.12.132.145 ([69.12.132.145]) (SquirrelMail authenticated user bmackey) by www.bmackey.com with HTTP; Sat, 14 Jul 2007 21:46:37 -0700 (PDT) X-Original-Message-ID: <2085.69.12.132.145.1184474797.squirrel@www.bmackey.com> X-Original-Date: Sat, 14 Jul 2007 21:46:37 -0700 (PDT) Subject: Re: Dimpled Firewalls From: "bob mackey" X-Original-To: lml@lancaironline.net User-Agent: SquirrelMail/1.4.9a MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Priority: 3 (Normal) Importance: Normal X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - global.delionsden.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [32015 2012] / [47 12] X-AntiAbuse: Sender Address Domain - yahoo.com X-Source: X-Source-Args: X-Source-Dir: > The fiberfax was not trimmed, just squeezed behind the stainless. > > Yes there is slight dimpling, so what? If there is a fire, the > jig will be up long before that connection gets hot enough to fail, > why add the extra weight? The reason to not have fiberfrax under the engine mount has nothing to do with fire protection. Instead, it is to avoid any crushable material that is being compressed by the bolt. The bolt can only do its job properly when it remains under sufficient tension. The relaxation of the fiberfrax can reduce the preload on the bolt, allowing motion in the joint. The motion then allows surface wear and fatigue. Unchecked, the engine eventually departs the airframe with unpleasant results for everyone. There aren't many bolts in a Lancair, but the ones that are there are pretty important. For a good education on bolted joints, try Carroll Smith's "Nuts, Bolts, and Fasteners". http://www.amazon.com/Fasteners-Plumbing-Handbook-Motorbooks-Workshop/dp/0879384069 ISBN: 0-87938-406-9 It's not a dry technical manual. It's written by an opinionated outspoken race car fabricator, and chock full of useful and interesting information. Read it cover to cover and you'll be a better airplane builder when you're done.