X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 02 Mar 2010 10:43:24 -0500 Message-ID: X-Original-Return-Path: Received: from sfa.gami.com ([68.89.254.162] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with ESMTP id 4143269 for lml@lancaironline.net; Tue, 02 Mar 2010 10:34:12 -0500 Received-SPF: none receiver=logan.com; client-ip=68.89.254.162; envelope-from=gwbraly@gami.com Received: from localhost (localhost.localdomain [127.0.0.1]) by sfa.gami.com (Postfix) with ESMTP id 8AEBF8F6 for ; Tue, 2 Mar 2010 09:33:41 -0600 (CST) Received: from gamimail1.Gami.local (mail.gami.com [10.10.10.33]) by sfa.gami.com (Postfix) with ESMTP id 520387BE for ; Tue, 2 Mar 2010 09:33:39 -0600 (CST) Received: from gamimail1.Gami.local ([10.10.12.14]) by gamimail1.Gami.local ([10.10.12.14]) with mapi; Tue, 2 Mar 2010 09:33:40 -0600 From: George Braly X-Original-To: Lancair Mailing List X-Original-Date: Tue, 2 Mar 2010 09:33:38 -0600 Subject: RE: [LML] Re: IV-P Turbo Blanket Thread-Topic: [LML] Re: IV-P Turbo Blanket Thread-Index: Acq5ZdgzXt5Mkh+nQG+6q839pIZELwAsvQTQ X-Original-Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Virus-Scanned: by amavisd-new-2.3.2 (20050629) (Debian) at gami.com I second Brent's well considered concerns. Take a look at the inside of a 2008, 2009, 2010 Cirrus Turbo for example= s of: 1) Effective fiber glass cowl protection with simple reflective tape materi= al on the inside (cowl stays cool to touch after shutdown near turbo). 2) General internal protection from infra-red from exhaust plumbing from he= at shields that still allow proper cooling of exhaust plumbing and the turb= o housing. Brent is right. Conformal heat shields on turbo hot sections are an invita= tion to coke the oil on the turbo bearings after shut down.=20 Regards, George =20 -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Bren= t Regan Sent: Monday, March 01, 2010 11:37 AM To: lml@lancaironline.net Subject: [LML] Re: IV-P Turbo Blanket I don't like the idea of insulating a turbocharger turbine housing as it ne= cessarily restricts heat flow from the housing both during operation and af= ter shut down. The Continentals have an alarmingly high maximum TIT of 1650= degrees F, necessitating the use of Inconel for the exhaust plumbing. Heat= is supplied to the turbo via the exhaust gas. Heat is rejected via the exh= aust gas, engine oil, conduction to the bearings and compressor and radiati= ve cooling. Radiative cooling climbs exponentially with temperature. Blocki= ng the flow of radiated heat causes the heat to go elsewhere, requiring tha= t the bearings, compressor and discharge oil are all incrementally hotter. After shut down, connective air currents quickly cool the turbine housing. = Keeping it warm in a blanket means the heat has more time to work on breaki= ng down the oil in the bearings. Finally, what about the headers? If the logic is that the source of the rad= iative heat has to be blocked to prevent having to insulate the cowling the= n the headers and crossover must also be insulated as they are exposed to t= he same hot gasses and their area is substantially greater than the turbine= housings. The best answer is to not insulate the turbos and to add a reflective shiel= d to the lower cowling such as Zetex A600 plus (see attached picture). This= addresses the heat from all sources without focusing it to sensitive areas= . Automotive, commercial, marine and truck turbos operate at lower TITs, and = diesels are much much lower. What works in one industry may not work in air= craft applications. Regards Brent Regan