Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Tue, 19 Oct 2004 23:21:55 -0400 Message-ID: X-Original-Return-Path: Received: from apollo.lunarpages.com ([64.235.234.15] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP-TLS id 479779 for lml@lancaironline.net; Tue, 19 Oct 2004 22:47:48 -0400 Received-SPF: none receiver=logan.com; client-ip=64.235.234.15; envelope-from=andreas@x-jets.com Received: from pcp02305123pcs.danbry01.ct.comcast.net ([68.63.153.191] helo=zorky.x-jets.com) by apollo.lunarpages.com with esmtpa (Exim 4.43) id 1CK6VP-0002ad-My for lml@lancaironline.net; Tue, 19 Oct 2004 19:47:16 -0700 X-Original-Message-Id: <6.1.2.0.0.20041019221002.035b00f0@apollo.lunarpages.com> X-Sender: andreas@x-jets.com@apollo.lunarpages.com X-Mailer: QUALCOMM Windows Eudora Version 6.1.2.0 X-Original-Date: Tue, 19 Oct 2004 22:52:45 -0400 X-Original-To: "Lancair Mailing List" From: Andreas Christou Subject: Re: [LML] Re: Plenum Cooling In-Reply-To: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - apollo.lunarpages.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [0 0] / [47 12] X-AntiAbuse: Sender Address Domain - x-jets.com X-Source: X-Source-Args: X-Source-Dir: At 09:53 PM 10/19/04, you wrote: >I am certainly no expert but I think the Bernoulli principle (an expanding >stream of air shows a reduction in velocity and an increase in pressure >and vice versa) applies if the expansion is generally non-turbulent, which >happens if the rate of expansion is around 5 degrees or less. In my >Legacy with a Lycoming engine, air intake on both sides was turbulent. On >the left much more on the right because the baffling angle is much steeper >to accommodate an oil cooler (which we installed elsewhere.) It is fairly >clear that no one did any airflow engineering on the intakes. We got some >significant temperature reductions (about 35 degrees CHT) from making some >minor alterations to the right side baffling (basically putting in a small >ramp that blocked about an inch of the #1 cylinder), installing about a 4" >deep cone on the left intake and a deflector to direct left intake air >down toward the #2 cylinder. The problem of air cooled engine cooling was given a great deal of attention by NACA in the years preceding WWII. Those early reports paid specific attention to air cooled radial engine cylinders and how to baffle for minimum drag losses. I found the reports on the NACA report server at http://naca.larc.nasa.gov/ I found this site to be a very useful source of information when designing a plenum based system for my Varieze. The same concepts were used to build a very successful plenum system for a Lancair 360. Subsequently, two articles were written for the canard community and these can be found at http://x-jets.com/a_cooling_efficiency.html and at http://x-jets.com/a_downdraft_cooling.html . You may find these articles informative. I gained 15 kts and lowered my CHT's by 70F. Andreas Andreas P. Christou Cell:(203) 470 7334 andreas@x-jets.com http://x-jets.com/