X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mx2.netapp.com ([216.240.18.37] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with ESMTPS id 4120851 for flyrotary@lancaironline.net; Thu, 11 Feb 2010 09:28:08 -0500 Received-SPF: softfail receiver=logan.com; client-ip=216.240.18.37; envelope-from=echristley@nc.rr.com X-IronPort-AV: E=Sophos;i="4.49,452,1262592000"; d="scan'208";a="314877501" Received: from smtp1.corp.netapp.com ([10.57.156.124]) by mx2-out.netapp.com with ESMTP; 11 Feb 2010 06:27:33 -0800 Received: from [10.62.16.80] ([10.62.16.80]) by smtp1.corp.netapp.com (8.13.1/8.13.1/NTAP-1.6) with ESMTP id o1BERWgD005277 for ; Thu, 11 Feb 2010 06:27:32 -0800 (PST) Message-ID: <4B7413D2.7090905@nc.rr.com> Date: Thu, 11 Feb 2010 09:27:30 -0500 From: Ernest Christley Reply-To: echristley@nc.rr.com User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: interesting cooling idea References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Bill Bradburry wrote: > > There have been a lot of these planes. Howard Hughes built the XF-11 > and damn nearly killed himself with it when it crashed in California. > > > > http://www.absoluteastronomy.com/topics/Contra-rotating_propellers > > > The LARC website from NASA had some studies of contra-rotating props that showed some significant efficiency increases when the blades were pitched and spaced correctly. It also allowed more power to be absorbed with a short prop, a problem that was starting to become a real headache for designers at the end of WWII. I am also a proponent of "suck air from around the spinner so that the inner portion of the prop becomes useful" school of thought. http://ernest.isa-geek.org/Delta/Pictures/EngineCowling2.jpg