X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [65.173.216.69] (account marv@lancaironline.net) by logan.com (CommuniGate Pro WEBUSER 5.2.2) with HTTP id 2865950 for lml@lancaironline.net; Mon, 21 Apr 2008 15:02:08 -0400 From: marv@lancair.net Subject: Re: [LML] prop diameter To: lml X-Mailer: CommuniGate Pro WebUser v5.2.2 Date: Mon, 21 Apr 2008 15:02:08 -0400 Message-ID: In-Reply-To: <004c01c8a3bb$29ec4120$6501a8c0@axs> References: <004c01c8a3bb$29ec4120$6501a8c0@axs> X-Priority: 3 MIME-Version: 1.0 Content-Type: text/plain;charset=iso-8859-1;format="flowed" Content-Transfer-Encoding: 8bit Posted for "terrence o'neill" : Thanks, Paul, An anecdote: for my book GM,DS! I interviewed Chuck Tucker, who lives in Hollister, CA. Chuck, with just his brother, himself entered TWO P-63s in the 1946 Cleveland National Air Races-- one in the Bendix and one in the Thompson....a Race 28 and Race 30. As and ex-Flying Tiger and Op officer of the very first US jet fighter squadron, he could fly everything from everything from P-39s asnd P-40s to the latest -63s, -51s and -38s, and said the -63 was the fastest at low altitude...so he bought two new ones war-surplus for a couple of thousand each. And modified them. Anyway, he told me "I don't know where these guys (other racers) get these ideas... putting bigger props on their planes. For speed, you want the smallest diameter your engine and handle." Chuck had friends at CalTech and at Lockheed, including Kelly Johnson. So, He qualified fastest for the finals in the Thompson, but had to drop out when his gear wouldn't come up ... (another story) ... So, smaller diameter for more speed. Keep the tips under Mcrit, and more blades to keep down the diameter, reducing the requried torque to turn it... as you said. Terrence