Return-Path: Sender: (Marvin Kaye) To: flyrotary Date: Sat, 19 Oct 2002 23:34:11 -0400 Message-ID: X-Original-Return-Path: Received: from [199.185.220.240] (HELO priv-edtnes44.telusplanet.net) by logan.com (CommuniGate Pro SMTP 4.0b9) with ESMTP id 1831995 for flyrotary@lancaironline.net; Fri, 18 Oct 2002 21:59:36 -0400 Received: from oemcomputer ([209.53.248.9]) by priv-edtnes44.telusplanet.net (InterMail vM.5.01.05.12 201-253-122-126-112-20020820) with SMTP id <20021019015931.KMRE3208.priv-edtnes44.telusplanet.net@oemcomputer> for ; Fri, 18 Oct 2002 19:59:31 -0600 From: "Haywire" X-Original-To: "Rotary motors in aircraft" Subject: RE: [FlyRotary] Re: Heat Exchanger Efficiency was Re: EWP Tech Data X-Original-Date: Fri, 18 Oct 2002 18:58:41 -0700 X-Original-Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) Importance: Normal X-MimeOLE: Produced By Microsoft MimeOLE V4.72.3110.3 In-Reply-To: > > Hey Marv, Ken, et al, > > Cooling is firstly a function of the heat exchanger's ability to reject > the heat transfered from the engine, and a function of the specific > heat of the coolant mediums. > I must make a confession here. I have strayed from the tried and tested GM A/C cores. I actually tried pairs of 2 different sizes and was unable to make them fit exactly as I wanted. I've read Tracy's report that due to the density of the heat exchanger, it is not as important to position them aligned with the air flow. I have no data to dispute this, but I just wanted to have them aligned with the flow anyways. I have the RV-7 cowl for the IO-360, which is slightly wider in this area, and yet I still could not fit them the way I wanted them. So, I got to thinking about the A/C performance of my Ford truck & my neighbors Chevy truck. We often alternate whose truck we would take on fishing trips, so I have spent many hours in both. Both trucks were new (bought within the same week) and yet we both agreed that my A/C was far better (we didn't agree on much else). Being as I've always been a Ford Powerstroke man, I decided to try these. The ford cores mounted perfectly where I wanted them, aligned with the cooling flow, with a very simple light weight mount. They were actually easier to weld on than the GM cores (different grade of alum?) I'm far happier with them than I would have been with the GM cores. The GM cores had a total volume of 623 cu" while the Ford cores have an area of 575 cu". The Ford cores are .5" thicker, but 1.5" narrower and ... damn, I forgot how many grams lighter, but it was enough. I reasoned that even with proper ducting, how much of this extra width will get proper airflow when you consider the area of the inlet. I won't be sharing any of this cooling air flow with any other heat exchangers. The oil will have a large NACA duct off the belly, the intercooler will have a small NACA duct off the side and combustion air will be fed from the top. With all of the airflow from the front inlets going through these rads, aligned with the airflow, I hope to get as sufficient cooling as the GM cores, but with a lighter installation. I realize that this may skew the EWP test results one way or the other. If I don't have sufficient cooling to begin with, I will change these and retest before I give up on the EWP. I thought I should share this, in case anyone has any concerns over the validity of these tests. S. Todd Bartrim Turbo 13B rotary powered RV-9endurance (FWF) C-FSTB http://www3.telus.net/haywire/RV-9/C-FSTB.htm