X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imf20aec.mail.bellsouth.net ([205.152.59.68] verified) by logan.com (CommuniGate Pro SMTP 5.0.4) with ESMTP id 888433 for flyrotary@lancaironline.net; Mon, 19 Dec 2005 13:25:02 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.152.59.68; envelope-from=atlasyts@bellsouth.net Received: from ibm62aec.bellsouth.net ([68.213.226.209]) by imf20aec.mail.bellsouth.net with ESMTP id <20051219181327.PCUJ27501.imf20aec.mail.bellsouth.net@ibm62aec.bellsouth.net> for ; Mon, 19 Dec 2005 13:13:27 -0500 Received: from [192.168.0.103] (really [68.213.226.209]) by ibm62aec.bellsouth.net with ESMTP id <20051219181327.HTIM28056.ibm62aec.bellsouth.net@[192.168.0.103]>; Mon, 19 Dec 2005 13:13:27 -0500 Mime-Version: 1.0 (Apple Message framework v746.2) Content-Transfer-Encoding: 7bit Message-Id: <36FB531D-E052-44BF-8E97-C268324C37F5@bellsouth.net> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed To: Rotary motors in aircraft , Props From: Buly Subject: Props Date: Mon, 19 Dec 2005 13:13:26 -0500 X-Mailer: Apple Mail (2.746.2) Yesterday somebody gave me the formulas to calculate the prop tip speed. I did some calculations and looks like us with the 2.17 redrives are kind of painted in the corner. Hope I'm wrong, but if I want to keep the tips from going supersonic, I have to cut down the prop to 64" or keep the engine below 5500 RPM. The choice is either inefficient prop and adequate power, or efficient long prop and not getting all the power from the engine? Am I wrong? Buly atlasyts@bellsouth.net