X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 20 Dec 2009 19:34:34 -0500 Message-ID: X-Original-Return-Path: Received: from imr-ma03.mx.aol.com ([64.12.206.41] verified) by logan.com (CommuniGate Pro SMTP 5.3c4) with ESMTP id 4031955 for lml@lancaironline.net; Sun, 20 Dec 2009 08:50:07 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.206.41; envelope-from=MikeEasley@aol.com Received: from imo-da04.mx.aol.com (imo-da04.mx.aol.com [205.188.169.202]) by imr-ma03.mx.aol.com (8.14.1/8.14.1) with ESMTP id nBKDnKot002222 for ; Sun, 20 Dec 2009 08:49:20 -0500 Received: from MikeEasley@aol.com by imo-da04.mx.aol.com (mail_out_v42.5.) id q.cf9.6bd4c2b1 (34979) for ; Sun, 20 Dec 2009 08:49:16 -0500 (EST) Received: from MikeNotebook (c-75-71-55-189.hsd1.co.comcast.net [75.71.55.189]) by cia-da08.mx.aol.com (v127.6) with ESMTP id MAILCIADA084-88a34b2e2b59c0; Sun, 20 Dec 2009 08:49:15 -0500 X-Original-Date: Sun, 20 Dec 2009 06:49:56 -0700 From: mikeeasley Subject: Re: [LML] Re: Firewall X-Original-To: "Lancair Mailing List" In-Reply-To: X-Original-Message-ID: References: X-Mailer: Nexus Desktop Client 3.1.20.1 MIME-Version: 1.0 Content-Type: MULTIPART/alternative; BOUNDARY=fec4e3a9-9f0a-4f90-b275-032e65f2525e Content-Transfer-Encoding: 8bit X-AOL-IP: 75.71.55.189 X-Spam-Flag:NO X-AOL-SENDER: MikeEasley@aol.com --fec4e3a9-9f0a-4f90-b275-032e65f2525e Content-Type: TEXT/plain; charset=us-ascii Here are a couple more concerns. Depending on what part of the firewall is exposed to the heat could make a huge difference on how quickly it fails. The oven baked pre-preg composite materials from Lancair have a higher Tg (glass transition temperature) than the room temperature layups that we do in our hangars. The firewall itself is more heat resistant than the layups holding it to the fuselage. And those edges aren't protected very well by the insulating blanket. It seems to me that even if you had a good blanket and took care of all the firewall penetrations, you could still have the entire firewall separate from the fuselage. If the heat was isolated on a small section of the firewall it shouldn't be a concern, but a full engine compartment fire is another story. I would also think that the engine mount steel would conduct heat right into the mounting bolts and hot bolts could cause the composite material around them to heat up and fail. I'm not sure how long that would take and whether coating the engine mount with something would help or not. Mike Easley Colorado Springs --fec4e3a9-9f0a-4f90-b275-032e65f2525e Content-Type: TEXT/html; charset=utf-8 Content-Transfer-Encoding: 8BIT

Here are a couple more concerns.

Depending on what part of the firewall is exposed to the heat could make a huge difference on how quickly it fails. The oven baked pre-preg composite materials from Lancair have a higher Tg (glass transition temperature) than the room temperature layups that we do in our hangars. The firewall itself is more heat resistant than the layups holding it to the fuselage. And those edges aren't protected very well by the insulating blanket. It seems to me that even if you had a good blanket and took care of all the firewall penetrations, you could still have the entire firewall separate from the fuselage. If the heat was isolated on a small section of the firewall it shouldn't be a concern, but a full engine compartment fire is another story.

I would also think that the engine mount steel would conduct heat right into the mounting bolts and hot bolts could cause the composite material around them to heat up and fail. I'm not sure how long that would take and whether coating the engine mount with something would help or not.

Mike Easley

Colorado Springs

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