X-Virus-Scanned: clean according to Sophos on Logan.com X-PolluStop-Diagnostic: (direct reply)\eX-PolluStop-Score: 0.00\eX-PolluStop: Scanned with Niversoft PolluStop 2.1 RC1, http://www.niversoft.com/pollustop Return-Path: Received: from fed1rmmtao05.cox.net ([68.230.241.34] verified) by logan.com (CommuniGate Pro SMTP 4.3c4) with ESMTP id 867234 for flyrotary@lancaironline.net; Wed, 13 Apr 2005 02:03:15 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.34; envelope-from=ALVentures@cox.net Received: from BigAl ([68.7.14.39]) by fed1rmmtao05.cox.net (InterMail vM.6.01.04.00 201-2131-118-20041027) with ESMTP id <20050413060229.WAMU7956.fed1rmmtao05.cox.net@BigAl> for ; Wed, 13 Apr 2005 02:02:29 -0400 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: Ram and Alt air Date: Tue, 12 Apr 2005 23:02:44 -0700 Message-ID: <000001c53fee$68f0e030$6400a8c0@BigAl> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6626 Importance: Normal In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Does the scoop get smaller with a higher top end? What would it be for 240 mph? Jerry ------------ I can't find my calcs for my scoop, so I guess you'll have to do the math. Engine displacement times rpm to get ingestion rate = air speed times x-sectional area of the opening. So, yes it gets smaller for higher speed for a given rpm, but higher speed for a given airplane requires higher rpm, and rpm goes up proportionally faster than airspeed. Confused yet? Tracy has about 3.5 sq in opening, I have about 5 for the 3-rotor; which seems pretty consistent. I'm sure Ed has all the numbers in his file, and he can look it up as soon as he's finished looking for pieces of apex seals.:) Al