X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 24 Nov 2008 06:08:25 -0500 Message-ID: X-Original-Return-Path: Received: from web55705.mail.re3.yahoo.com ([216.252.110.36] verified) by logan.com (CommuniGate Pro SMTP 5.2.10) with SMTP id 3314116 for lml@lancaironline.net; Mon, 24 Nov 2008 00:19:05 -0500 Received: (qmail 26370 invoked by uid 60001); 24 Nov 2008 05:19:07 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:MIME-Version:Content-Type:Message-ID; b=EBQwqSz8MJrgJpHQhhFtT4o+TKmaSSTZX1FrmAW3Nz5DOFlFHPxN/lbw9I7KNluzzxq09YKOU1FfGfzxr+Na7mshYKRf6Eua5aBYIE3BmhuR0BYaxrIt88hj7tceir0yw64LraNxTU81WyPggugAOq9Yu0gmQ+w422ibd6B5i7A=; X-YMail-OSG: 2WPKlIUVM1lkDiu5.rVoVcGnm10QpwlIjD4VZ4Y5.VUu.IXr7FHC7e.x3erCnPiYkrZXlFLfw099x4FQNlubFkZkRP1MKsn.1XorcZYBKsrBBOKbzbDk.8bd.w9d4dtg6vCwpCHVDOyyWfmBDtLEdBrqzG1quGmLM2eD5ZmnaDVEkFlkivz8U_oJjnVG Received: from [75.33.110.78] by web55705.mail.re3.yahoo.com via HTTP; Sun, 23 Nov 2008 21:19:06 PST X-Mailer: YahooMailRC/1155.32 YahooMailWebService/0.7.260.1 References: X-Original-Date: Sun, 23 Nov 2008 21:19:06 -0800 (PST) From: J H Webb Subject: Re: [LML] 320 Carb Heat Box X-Original-To: Lancair Mailing List MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1822408439-1227503946=:26163" X-Original-Message-ID: <947894.26163.qm@web55705.mail.re3.yahoo.com> --0-1822408439-1227503946=:26163 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Larry,=0A=0A=A0=A0 I have not measured the temperatures in the lower cowl, = but I have participated in lower cowl temperatures in several GA aircraft a= nd it is very difficult to find a source with adequate volume and temperatu= re. Additionally the temperature in the cowl varies with AOA, IAS, and engi= ne power. Plus there is heat loss from the source to the carb. =0A=A0=A0=A0= When this is all considered it is virtually impossible to find a suitable = source for hot air to provide carb deicing.=A0 Then consider under proper c= onditions the temperature drop in the venturi can be 90 degrees F. So you r= eally need hot air at the source to produce at least 100 degrees at the car= b.=0A=A0=A0=A0 The FAA spec for this was written in blood, so it is very cr= itical, airplanes have been lost in the past.=0A=0AJack Webb=0ABASE=0AL360,= LIV=0A=0A=0A=0A=0A________________________________=0AFrom: Larry Henney =0ATo: lml@lancaironline.net=0ASent: Friday, November 21= , 2008 6:27:54 PM=0ASubject: [LML] 320 Carb Heat Box=0A=0A=0AGuys,=0A=A0=0A= I've got a friend looking at his 320 carb heat intake box.=A0 The question = is; Does lower cowl air have enough heat in it to prevent carb ice?=A0 He i= s considering muffing an exhaust pipe to make sure the heated air is adequa= tely hot.=A0 =0A=A0=0AI was wondering if others have ever had carb ice with= the standard Lancair carb heat box (using just lower cowl hot (warm)=A0air= )?=A0 =0A=A0=0AWe'd appreciate your thoughts.=0A=A0=0ALarry Henney=0A=0A=0A= --0-1822408439-1227503946=:26163 Content-Type: text/html; charset=us-ascii

Larry,

I have not measured the temperatures in the lower cowl, but I have participated in lower cowl temperatures in several GA aircraft and it is very difficult to find a source with adequate volume and temperature. Additionally the temperature in the cowl varies with AOA, IAS, and engine power. Plus there is heat loss from the source to the carb.

When this is all considered it is virtually impossible to find a suitable source for hot air to provide carb deicing. Then consider under proper conditions the temperature drop in the venturi can be 90 degrees F. So you really need hot air at the source to produce at least 100 degrees at the carb.

The FAA spec for this was written in blood, so it is very critical, airplanes have been lost in the past.

Jack Webb

BASE

L360, LIV

From: Larry Henney <LHenney@charter.net>
To: lml@lancaironline.net
Sent: Friday, November 21, 2008 6:27:54 PM
Subject: [LML] 320 Carb Heat Box

Guys,

I've got a friend looking at his 320 carb heat intake box. The question is; Does lower cowl air have enough heat in it to prevent carb ice? He is considering muffing an exhaust pipe to make sure the heated air is adequately hot.

I was wondering if others have ever had carb ice with the standard Lancair carb heat box (using just lower cowl hot (warm) air)?

We'd appreciate your thoughts.

Larry Henney

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