Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Mon, 20 Oct 2003 22:46:00 -0400 Message-ID: X-Original-Return-Path: Received: from [24.93.67.84] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.1.5) with ESMTP id 2642997 for flyrotary@lancaironline.net; Sun, 19 Oct 2003 22:23:53 -0400 Received: from o7y6b5 (clt78-020.carolina.rr.com [24.93.78.20]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id h9K2Nnuf018845 for ; Sun, 19 Oct 2003 22:23:50 -0400 (EDT) X-Original-Message-ID: <001301c396b0$f6691c40$1702a8c0@WorkGroup> From: "Ed Anderson" X-Original-To: "Rotary motors in aircraft" Subject: Cooling Model Enhancement X-Original-Date: Sun, 19 Oct 2003 22:22:08 -0400 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 I finally found a math model that provides the rise in temperature as it goes through a radiator. The model indicates that for the two evaporator cores that the air temp should rise between 35F and 38F for 161 HP at 120 MPH burning 15 GPH. Less of a rise if less BTU are being generated. Here is what the temp rise model gives (all temps in farenheit): OAT Delta T Exit Radiator 0 34.9 34.9 30 35.59 65.59 60 36.15 96.15 90 36.02 126.02 120 37.48 157.48 I guess I am surprised to find that the delta T is decreasing with decreasing OAT. The only way I can rationalize the lower delta T at the lower temps still removing the same amount of heat is that the cold air is denser and therefore the mass flow is greater and that accounts for carring away the same amount of heat with a lower Delta T. Would any of your thermodynamic folks comment on this? In any case, it appears that some of Todd's delta T figures fall in this ball park, so this model may not be too far off. Ed Anderson RV-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com