X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-d22.mx.aol.com ([205.188.144.208] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2465146 for flyrotary@lancaironline.net; Sat, 10 Nov 2007 12:01:43 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.144.208; envelope-from=BMears9413@aol.com Received: from BMears9413@aol.com by imo-d22.mx.aol.com (mail_out_v38_r9.3.) id q.c74.1d10966c (34988) for ; Sat, 10 Nov 2007 12:01:01 -0500 (EST) Received: from webmail-dd09 (webmail-dd09.webmail.aol.com [205.188.104.9]) by cia-db01.mx.aol.com (v120.9) with ESMTP id MAILCIADB011-88ac4735e3cd387; Sat, 10 Nov 2007 12:01:01 -0400 References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: Burns Stainless Drag Muffler Date: Sat, 10 Nov 2007 12:01:01 -0500 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: bmears9413@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8C9F1D268375448_560_F5E2_webmail-dd09.sysops.aol.com" X-Mailer: AOL WebMail 31361-STANDARD Received: from 65.182.71.8 by webmail-dd09.sysops.aol.com (205.188.104.9) with HTTP (WebMailUI); Sat, 10 Nov 2007 12:01:01 -0500 Message-Id: <8C9F1D268375448-560-792D@webmail-dd09.sysops.aol.com> X-AOL-IP: 205.188.104.9 X-Spam-Flag: NO ----------MB_8C9F1D268375448_560_F5E2_webmail-dd09.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" I will build a heat shield between the intake and exhaust also. Plus I will=20= have cooling coming in from above the spinner and exhausting around the exha= ust pipes themselves. So Im still mixed on wrapping or not, since I now have= recomendations both ways. I know I will wrap where the exhaust runs over th= e redrive to insure it doesnt absorb too much heat. I may leave ther others=20= alone since they are jet coated inside and out. Bob Mears Supermarind Spitfire -----Original Message----- From: Al Gietzen To: Rotary motors in aircraft Sent: Sat, 10 Nov 2007 10:38 am Subject: [FlyRotary] Re: Burns Stainless Drag Muffler =C2=A0 I planned on wrapping the entire exhaust system to keep the heat put of the=20= engine compartment. You think thats a bad plan? Bob Mears Supermarine Spitfire My opinion is that it is a bad idea.=C2=A0 It significantly increases the wa= ll temps of the exhaust system, and makes inspection very difficult. =C2=A0T= he one thing that I would consider is coating of the inside surfaces; the pr= imary benefit of which would be increased emissivity (reduce radiant heating= ) since the insulating effect of the thin coatings are small. The actual ben= efit is unknown since exhaust products would undoubtedly plate out on the in= side surface, and the emissivity may soon be quite the same as without coati= ng. Add radiation baffles between the exhaust and any nearby surfaces that you d= o not want to be heated.=C2=A0 Allow air flow around the exhaust system for=20= cooling.=C2=A0 Just as an example, I placed a SS baffle over the manifold/mu= ffler as separation from the induction system, small baffles protecting the=20= engine mounts, and reflective heat shield on the redrive, as well as on the=20= inside of the top cowling. I added a small NACA scoop in the bottom cowl wit= h airflow directed on to the exhaust system from below.=20 The exit air from the in-cowl radiator goes into the cowling, and my measure= d in-cowl air temps on the exhaust system side during flight are generally l= ess than 150F =E2=80=93 not an issue. Hope this helps =E2=80=93 works for me. Al -- omepage: http://www.flyrotary.com/ rchive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.ht= ml [Image Removed]=20 ________________________________________________________________________ Email and AIM finally together. You've gotta check out free AOL Mail! - http= ://mail.aol.com ----------MB_8C9F1D268375448_560_F5E2_webmail-dd09.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8" I will build a heat shield between the intake and exhaust also. Plus I will=20= have cooling coming in from above the spinner and exhausting around the exha= ust pipes themselves. So Im still mixed on wrapping or not, since I now have= recomendations both ways. I know I will wrap where the exhaust runs over th= e redrive to insure it doesnt absorb too much heat. I may leave ther others=20= alone since they are jet coated inside and out.


Bob Mears
Supermarind Spitfire


-----Original Message-----
From: Al Gietzen <ALVentures@cox.net>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Sat, 10 Nov 2007 10:38 am
Subject: [FlyRotary] Re: Burns Stainless Drag Muffler

 
I planned on wrapping the entire exhaust system to keep the heat=20= put of the engine compartment. You think thats a bad plan?
Bob Mears
Supermarine Spitfire
My opinion is that=20= it is a bad idea.  It significantly increases the wall temps of the exh= aust system, and makes inspection very difficult.  The one thing that I= would consider is coating of the inside surfaces; the primary benefit of wh= ich would be increased emissivity (reduce radiant heating) since the insulat= ing effect of the thin coatings are small. The actual benefit is unknown sin= ce exhaust products would undoubtedly plate out on the inside surface, and t= he emissivity may soon be quite the same as without coat= ing.
Add radiation baffl= es between the exhaust and any nearby surfaces that you do not want to be he= ated.  Allow air flow around the exhaust system for cooling.  Just= as an example, I placed a SS baffle over the manifold/muffler as separation= from the induction system, small baffles protecting the engine mounts, and=20= reflective heat shield on the redrive, as well as on the inside of the top c= owling. I added a small NACA scoop in the bottom cowl with airflow directed=20= on to the exhaust system from below.
The exit air from t= he in-cowl radiator goes into the cowling, and my measured in-cowl air temps= on the exhaust system side during flight are generally less than 150F =E2= =80=93 not an issue.
Hope this helps=20= =E2=80=93 works for me.
Al

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