Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Sat, 23 Nov 2002 20:01:00 -0500 Message-ID: X-Original-Return-Path: Received: from [64.4.38.145] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.0.1) with ESMTP id 1885206 for flyrotary@lancaironline.net; Sat, 23 Nov 2002 13:36:29 -0500 Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Sat, 23 Nov 2002 10:36:29 -0800 X-Originating-IP: [65.137.50.6] Reply-To: "Tracy Crook" From: "Tracy Crook" X-Original-To: "Rotary motors in aircraft" References: Subject: Re: Air Temp Rise through oil cooler X-Original-Date: Sat, 23 Nov 2002 13:45:07 -0500 Organization: Real World Solutions Inc. MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Original-Message-ID: X-OriginalArrivalTime: 23 Nov 2002 18:36:29.0493 (UTC) FILETIME=[3CE86E50:01C2931F] Yesterday I measured the air temprise through my oil cooler. Paul Lamar had told me that typical figures should be around 10 degrees for an efficient system. This sounded wrong to me (I know, he hates that) because in my "mental model" of an efficient aircraft cooling system, it is best to use the fewest cubic feet of cooling air possible. Every CF of cooling air used represents drag. This means that we must remove more BTU per CF of air, i.e. we need to heat it up as much as possible. The ambient air temp at time of test flight was 66 deg. F. Air exiting the oil cooler was between 106 and 111 deg F., depending on power setting. This is a 40 - 45 deg temp increase. I was surprised at the small range of temps at first but when you factor in the increased flow at higher power settings, it makes sense. Today I'm going to measure the outlet air from the right side evaporator core. Ed Andersen is going to be doing similar measurements on his plane and it will be interesting to compare the results. Tracy Crook