Return-Path: Received: from mail.tsisp.com ([65.23.108.44] verified) by logan.com (CommuniGate Pro SMTP 4.2b6) with ESMTP-TLS id 220014 for flyrotary@lancaironline.net; Sun, 20 Jun 2004 20:35:52 -0400 Received: from stevehome by mail.tsisp.com (Technical Support Inc.) with SMTP id CQA74584 for ; Sun, 20 Jun 2004 20:35:19 -0400 Reply-To: From: "Steve Brooks" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: temps better, but ... Date: Sun, 20 Jun 2004 20:36:21 -0400 Message-ID: <003701c45727$c9070cc0$6400a8c0@WORKGROUP.local> 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 CWS, Build 9.0.2416 (9.0.2910.0) In-Reply-To: X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Importance: Normal Dale, Thanks for the suggestions. I've been making modifications to help the air flow, but only saw a marginal improvement. I'm using the stock 2nd gen oil cooler, and 1 Howe 13X19 aluminum radiator. The cooler and radiator are mounted under the engine and fed by the Cozy NACA scoop. I also placed vortex generators just behind the landing brake, which did make a big improvement. I installed some curved deflectors, one on the oil cooler and 2 on the radiator to help the incoming air make the upward turn and flow through. My next step, and one I've been trying to avoid, is to increase the air inlet size/depth, to move it out of the boundary layer. I think that the significant change that I saw with the vortex generators were a good sign that the scoop is in slower air. I have a new scoop the will mount to the landing gear cover, and butt up to the original scoop, to capture higher speed air. Steve Brooks Cozy MKIX N75CZ Turbo Rotary -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Dale Rogers Sent: Sunday, June 20, 2004 10:21 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: temps better, but ... Steve Brooks wrote: > My engine is now running pretty good and idles very well at 1000 RPMs. My > only rough spot is somewhere around 1500, it stumbles occasionally. Mainly > when the engine is hot. Now if I could just get my temperatures down > another 15 degrees I'd have it made. Steve, I know this may have already been covered, but the principles were brought back to me very strongly a few days ago, climbing from Phoenix to Flagstaff (on the road). A cooling system temperature that is linked to throttle position is a sure sign of insufficient capacity. (An a side to Rusty, who will understand: new *company* mini-van - a Chevy Venture - can't make that climb without turning off the A/C. Thank you, cheapskates at corporate fleet!) How many cubic inches of heat exchanger do you have? How is the airflow through it managed? IIRC, most folks here who are flying are getting the best results with an inlet of 1/4 to 1/3 the area of radiator. How sharp of an angle does the airflow have to negotiate? Can you re- shape the plenum to gently "steer" the air into nearly perpendicular to the radiator surface? How is the flow beyond the radiator managed? Is there room for expansion? Is the heated air competing for expansion space with air heated by the exhaust system? If so, your outlet area needs to be sized up to allow for the combined sources. Some things to look at. Dale R. COZY MkIV-R13B #1254 >> Homepage: http://www.flyrotary.com/ >> Archive: http://lancaironline.net/lists/flyrotary/List.html