X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 26 Sep 2005 11:15:25 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d21.mx.aol.com ([205.188.144.207] verified) by logan.com (CommuniGate Pro SMTP 5.0c2) with ESMTP id 733436 for lml@lancaironline.net; Mon, 26 Sep 2005 10:09:26 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.144.207; envelope-from=Mquinns@aol.com Received: from Mquinns@aol.com by imo-d21.mx.aol.com (mail_out_v38_r5.5.) id q.1ad.3fb61c94 (15974) for ; Mon, 26 Sep 2005 10:08:32 -0400 (EDT) Received: from FWM-R40 (fwm-r40.webmail.aol.com [152.163.181.144]) by air-id10.mx.aol.com (v107.13) with ESMTP id MAILINID101-3e66433800e0219; Mon, 26 Sep 2005 10:08:32 -0400 X-Original-Date: Mon, 26 Sep 2005 10:08:32 -0400 X-Original-Message-Id: <8C790BAE99613E7-744-B3B8@FWM-R40.sysops.aol.com> From: mquinns@aol.com References: Received: from 207.126.196.16 by FWM-R40.sysops.aol.com (152.163.181.144) with HTTP (WebMailUI); Mon, 26 Sep 2005 10:08:32 -0400 X-MB-Message-Source: WebUI X-MB-Message-Type: User In-Reply-To: X-Mailer: AOL WebMail 1.1.0.14204 Subject: Re: [LML] Engine Cooling and Cabin Heat Content-Type: multipart/alternative; boundary="--------MailBlocks_8C790BAE99613E7_744_A767_FWM-R40.sysops.aol.com" MIME-Version: 1.0 X-Original-To: lml@lancaironline.net X-AOL-IP: 152.163.181.144 X-Spam-Flag: NO ----------MailBlocks_8C790BAE99613E7_744_A767_FWM-R40.sysops.aol.com Content-Type: text/plain; charset="us-ascii" William, I am still in the building phase myself but have considered doing the same thing because of the issues you outlined. After visiting Sun-N-Fun this year, I decided not to do it. While looking at Bruce Bohannon' airplane, two mechanics removed the upper cowling. The rear shrouding of the high pressure upper deck had two very large oil coolers (one on each side). I asked the mechanics how this was possible with the demanding cooling needs at high altitude (thin air). They said that the oil coolers actually lowered engine temperature even though high pressure air was being routed away from the engine. They explained that testing had determined that plenty of air was getting in the cowling and was actually backing-up at the inlets. Narrowing of the intake openings was considered but rejected in favor of more oil cooling. I am not an expert but what they said made sense in lieu of actual testing on my plane when it finally flies. You might want to try some testing before proceeding with your plan. Mark Quinn 360... 80% -----Original Message----- From: william rumburg To: Lancair Mailing List Sent: Fri, 23 Sep 2005 22:26:05 -0400 Subject: [LML] Engine Cooling and Cabin Heat 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 Rumburg N403WR (Sonic bOOm) ----------MailBlocks_8C790BAE99613E7_744_A767_FWM-R40.sysops.aol.com Content-Type: text/html; charset="us-ascii"

William,

I am still in the building phase myself but have considered doing the same thing because of the issues you outlined. After visiting Sun-N-Fun this year, I decided not to do it. While looking at Bruce Bohannon' airplane, two mechanics removed the upper cowling. The rear shrouding of the high pressure upper deck had two very large oil coolers (one on each side). I asked the mechanics how this was possible with the demanding cooling needs at high altitude (thin air). They said that the oil coolers actually lowered engine temperature even though high pressure air was being routed away from the engine. They explained that testing had determined that plenty of air was getting in the cowling and was actually backing-up at the inlets. Narrowing of the intake openings was considered but rejected in favor of more oil cooling.

I am not an expert but what they said made sense in lieu of actual testing on my plane when it finally flies. You might want to try some testing before proceeding with your plan.

Mark Quinn

360... 80%

-----Original Message-----
From: william rumburg <lancair403@earthlink.net>
To: Lancair Mailing List <lml@lancaironline.net>
Sent: Fri, 23 Sep 2005 22:26:05 -0400
Subject: [LML] Engine Cooling and Cabin Heat

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 Rumburg

N403WR (Sonic bOOm)

----------MailBlocks_8C790BAE99613E7_744_A767_FWM-R40.sysops.aol.com--