X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 24 Sep 2005 22:54:41 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d23.mx.aol.com ([205.188.139.137] verified) by logan.com (CommuniGate Pro SMTP 5.0c2) with ESMTP id 731628 for lml@lancaironline.net; Fri, 23 Sep 2005 23:52:24 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.139.137; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-d23.mx.aol.com (mail_out_v38_r5.5.) id q.d2.31f2bc76 (48576) for ; Fri, 23 Sep 2005 23:51:31 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Fri, 23 Sep 2005 23:51:31 EDT Subject: Re: [LML] Engine Cooling and Cabin Heat X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1127533891" X-Mailer: 9.0 Security Edition for Windows sub 5009 X-Spam-Flag: NO -------------------------------1127533891 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 9/23/2005 9:26:34 P.M. Central Standard Time, lancair403@earthlink.net writes: Engine cooling air inlets on my 320 cowl measured about 3-3/4 inches circular as the molded parts were received. I'm certain they were designed to be four inches and, even at that, are marginal in order to minimize cooling drag. I enlarged them to the four inch dimension and believe it to be a smart move. CHTs for my IO-320 are about 400 on climb out and 360 to 380 in cruise (dependent on altitude and power setting) which isn't bad, but I'd like to see them a little lower. My only intentional drain of engine cooling air was a 1/2 inch tube to cool the gascolator and electric boost pump; however, when the cabin heat valve was recently discussed, I realized that valve supplied by Lancair exhausts air overboard when closed and is thus a useless drain of cooling air - if it's source is a 1-1/2 opening in the baffling. Am I correct and would installing a seperate NACA duct to supply air to the cabin heat valve result in lower CHTs? Bill, Probably not. In the summer I put a reducer plate over the cabin heat intake in the baffling that reduces it to a 1/2" hole (some air is needed to keep from burning things up). This does not alter the other 3 air takeoffs - vacuum pump shroud, voltage regulator blast tube and alternator cooling tube. There are so many ways to improve engine cooling - perhaps you should first measure the pressure differential between the upper and lower cowl. If it is at or above 7" H2O, you have enough of a differential. I have opened up the lower baffle in front of cyl #2 and put a block in front of cyl #1. Now #4 is the hottest and it will receive attention next. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) -------------------------------1127533891 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 9/23/2005 9:26:34 P.M. Central Standard Time,=20 lancair403@earthlink.net writes:

<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>

Engine cooling air inlets on my 320 cowl measured abou= t=20 3-3/4 inches circular as the molded parts were received. I'm certain they=20= were=20 designed to be four inches and, even at that, are marginal in order t= o=20 minimize cooling drag. I enlarged them to the four inch dimensio= n=20 and believe it to be a smart move. CHTs for my IO-320 are a= bout=20 400 on climb out and 360 to 380 in cruise (dependent on altitude and power= =20 setting) which isn't bad, but I'd like to see them a little lower.

My only intentional drain of engine cooling air was a 1/2=20 inch tube to cool the gascolator and electric boost pump; howeve= r,=20 when the cabin heat valve was recently discussed, I realized that val= ve=20 supplied by Lancair exhausts air overboard when closed and is thus=20 a useless drain of cooling air - if it's source is a 1-1/2 opening in= the=20 baffling.

Am I correct and would installing a seperate NACA=20 duct to supply air to the cabin heat valve result in l= ower=20 CHTs?

Bill,

Probably not.

In the summer I put a reducer plate over the cabin heat intake in the=20 baffling that reduces it to a 1/2" hole (some air is needed to keep fro= m=20 burning things up). This does not alter the other 3 air takeoffs - vac= uum=20 pump shroud, voltage regulator blast tube and alternator cooling tube.

There are so many ways to improve engine cooling - perhaps you should f= irst=20 measure the pressure differential between the upper and lower cowl. If= it=20 is at or above 7" H2O, you have enough of a differential. I have opene= d up=20 the lower baffle in front of cyl #2 and put a block in front of cyl #1. = ;=20 Now #4 is the hottest and it will receive attention next.=20

Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)

-------------------------------1127533891--