X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 10 Apr 2008 17:49:18 -0400 Message-ID: X-Original-Return-Path: Received: from elasmtp-mealy.atl.sa.earthlink.net ([209.86.89.69] verified) by logan.com (CommuniGate Pro SMTP 5.2.1) with ESMTP id 2841474 for lml@lancaironline.net; Thu, 10 Apr 2008 10:05:54 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.69; envelope-from=colyncase@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=obSBUxMr1Kzui2CbKTJOva66+dfKZHVb+m6ElGi2etYsouh/PDoyWyMX4qf2onJl; h=Received:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE:X-ELNK-Trace:X-Originating-IP; Received: from [97.91.158.76] (helo=ccaselt3) by elasmtp-mealy.atl.sa.earthlink.net with esmtpa (Exim 4.67) (envelope-from ) id 1JjxOs-0002i3-TJ for lml@lancaironline.net; Thu, 10 Apr 2008 10:05:15 -0400 X-Original-Message-ID: <00a201c89b13$e6375910$6501a8c0@nvidia.com> From: "Colyn Case at earthlink" X-Original-To: "Lancair Mailing List" References: Subject: Re: [LML] Re: legacy exhaust heat shield option X-Original-Date: Thu, 10 Apr 2008 09:05:14 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_009F_01C89AE9.FCFD1100" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 X-ELNK-Trace: 63d5d3452847f8b1d6dd28457998182d7e972de0d01da940c2dcdce1f25a98d5a4ddc4050c579a2b350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 97.91.158.76 This is a multi-part message in MIME format. ------=_NextPart_000_009F_01C89AE9.FCFD1100 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable It's an issue of burning the paint aft of the existing insulation = blanket and above the exhaust tip. Also, the strength of a carbon = composite structural panel is reduced while at elevated temperatures. I happen to have just measured temps around my LIVP exhaust to get a = baseline for an alternate exhaust pipe. My stock pipes are aimed down = at a 45 degree angle, so it's about as cold as you could get in the IVP = installation. The hottest point I measured.....and this was just going = around the pattern, not at high cruise with the TIT maxed...was right = about 200. With a more streamlined exhaust I would expect way higher. I'm told prepreg epoxy starts to soften at 250 while high quality epoxy = that we use for hand layups is down around 170 dF. (boat epoxy is down = at 120 dF) Doesn't seem like a good match for the fire wary. I recently = got to observe what happens if you have a leaky exhaust slip joint, for = example. Having another layer of metal nearby strikes me as a good idea ------=_NextPart_000_009F_01C89AE9.FCFD1100 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

It's=20 an issue of burning the paint aft of the existing insulation blanket and = above=20 the exhaust tip. Also, the strength of a carbon composite = structural panel=20 is reduced while at elevated temperatures.

I happen to have just measured = temps around=20 my LIVP exhaust to get a baseline for an alternate exhaust pipe. = My stock=20 pipes are aimed down at a 45 degree angle, so it's about as cold as you = could=20 get in the IVP installation. The hottest point I = measured.....and=20 this was just going around the pattern, not at high cruise with the TIT=20 maxed...was right about 200. With a more streamlined exhaust = I would=20 expect way higher.

I'm told prepreg epoxy starts to = soften at=20 250 while high quality epoxy that we use for hand layups is down around = 170=20 dF. (boat epoxy is down at 120 dF) Doesn't seem like a good match = for the=20 fire wary. I recently got to observe what happens if you have a = leaky=20 exhaust slip joint, for example. Having another layer of = metal=20 nearby strikes me as a good idea

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