Return-Path: Sender: (Marvin Kaye) To: lml Date: Wed, 07 May 2003 08:59:03 -0400 Message-ID: X-Original-Return-Path: Received: from fep01-app.kolumbus.fi ([193.229.0.41] verified) by logan.com (CommuniGate Pro SMTP 4.1b4) with ESMTP id 2336065 for lml@lancaironline.net; Wed, 07 May 2003 03:51:38 -0400 Received: from fiz1ms03 ([194.211.242.142]) by fep01-app.kolumbus.fi with SMTP id <20030507075136.TNNZ639.fep01-app.kolumbus.fi@fiz1ms03> for ; Wed, 7 May 2003 10:51:36 +0300 Received: from fid1ms33.fid1.root4.net ([158.233.139.202]) by fid1ms31.fid1.root4.net with Microsoft SMTPSVC(5.0.2195.5329); Wed, 7 May 2003 10:50:26 +0300 Received: from s60a591.hk.unibank.dk ([10.137.10.33]) by fid1ms33.fid1.root4.net with Microsoft SMTPSVC(5.0.2195.5329); Wed, 7 May 2003 10:49:24 +0300 Received: from s60a09f.hk.unibank.dk (unverified) by s60a591.hk.unibank.dk (Content Technologies SMTPRS 4.2.10) with ESMTP id for ; Wed, 7 May 2003 09:49:22 +0200 Received: from smtpfil.fil.unibank.dk ([10.137.10.116]) by s60a09f.hk.unibank.dk (Lotus Domino Release 5.0.12) with ESMTP id 2003050709492160:32876 ; Wed, 7 May 2003 09:49:21 +0200 Subject: Re: [LML] oil cooler air flow X-Original-To: Lancair Mailing List X-Mailer: Lotus Notes Release 5.0.3 (Intl) 21 March 2000 X-Original-Message-ID: From: villi.seemann@nordea.com X-Original-Date: Wed, 7 May 2003 09:49:20 +0200 MIME-Version: 1.0 X-MIMETrack: Serialize by Router on HHHHUB02/UNIBANK(Release 5.0.6a |January 17, 2001) at 07-05-2003 09:50:59, Itemize by SMTP Server on JUPITER/Nordea_Ext12(Release 5.0.12 |February 13, 2003) at 07-05-2003 09:49:21, Serialize by Router on JUPITER/Nordea_Ext12(Release 5.0.12 |February 13, 2003) at 07-05-2003 09:49:22, Serialize complete at 07-05-2003 09:49:22 Content-type: text/plain; charset="us-ascii" X-Original-Return-Path: villi.seemann@nordea.com X-OriginalArrivalTime: 07 May 2003 07:49:24.0514 (UTC) FILETIME=[2D938820:01C3146D] Hi Listers I feel for throwing in my 2 cents worth. It appears to me that most participants in the discussion, focus on air inlet to the oil cooler. In my opinion the main point to get any heat transfere is air flow. Air flow is a function of pressure differential. If you do not have sufficient pressure differentian between 'front' and 'back' side of the oil cooler, you will not get sufficient air flow, to take the heat out of the oil. Having the oil cooler sitting in front of no 2 cylinder (on a 4 cyl eng) is a good thing - if the inlet air is not stallet due to turbulence or lack of trumpet function in the start of the plenum chamber. NACA ducts on the cowling are another good solution - if they are not placed where aerodynamics makes a low pressure at the location of the duct intake. Not only do one have to ensure there is a high pressure on the air inlet side, but you also have to ensure there is not a back pressure on the outlet side of the cooler. When cooling air for the engine enters the plenum chamber, usually above the cylinders, it builds a pressure, to force the air down and around the cylinders. Hereby the air is heated and expands, and if the volume or the exit of the room below the cylinder is insufficient, it will build up a back pressure. If the pressure in the area below the cylinders are too high to make a positive pressure differential between the sides of the oil cooler, it doesn't help you have got access to all the air in the sky, if there is no force to move it through you cooler. Usually the area of the cooling air outlet, should be many times the area of the air inlet, a) to give sufficient cooling, b) not to buil up too much cooling drag. Please bear with my poor/unusual english, as it is not my mothertongue. Regards Villi H. Seemann Senior Engineer Infrastructure Network Phone (+45) 3333 2101 FAX (+45) 3333 1130 CellPhn (+45)2220 7690