X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 14 Sep 2008 22:56:03 -0400 Message-ID: X-Original-Return-Path: Received: from mta11.adelphia.net ([68.168.78.205] verified) by logan.com (CommuniGate Pro SMTP 5.2.8) with ESMTP id 3131982 for lml@lancaironline.net; Sun, 14 Sep 2008 20:08:41 -0400 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.205; envelope-from=super_chipmunk@roadrunner.com Received: from Laptop ([74.75.176.139]) by mta11.adelphia.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with SMTP id <20080915000356.WHCL2068.mta11.adelphia.net@Laptop> for ; Sun, 14 Sep 2008 20:03:56 -0400 X-Original-Message-ID: From: "Bill Wade" X-Original-To: "Lancair Mailing List" Subject: Bolting carbon X-Original-Date: Sun, 14 Sep 2008 20:08:07 -0400 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6001.18000 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 I was torquing the -4 hardware for the corner brackets on the main gear box (IV-P) and noticed they kept relaxing. I would tighten to 70 inch-pounds (the max listed in AC 43.13) then come back later and find they had loosened so that it might require a quarter turn or more to regain the value. This happened several times and I started to wonder if the carbon might be getting crushed. Today I found that the bolts had stayed at 70 but now I'm wondering about the added stress that pressurization might put on the material under the heads. As the range for the fastener is 50-70 inch pounds would it be a good idea to use a lower value? What have others done? Thanks- Bill Wade