X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rtp-iport-2.cisco.com ([64.102.122.149] verified) by logan.com (CommuniGate Pro SMTP 5.2c4) with ESMTP id 2634388 for flyrotary@lancaironline.net; Mon, 07 Jan 2008 09:36:51 -0500 Received-SPF: softfail receiver=logan.com; client-ip=64.102.122.149; envelope-from=echristley@nc.rr.com X-IronPort-AV: E=Sophos;i="4.24,253,1196658000"; d="scan'208";a="143440684" Received: from rtp-dkim-1.cisco.com ([64.102.121.158]) by rtp-iport-2.cisco.com with ESMTP; 07 Jan 2008 09:36:11 -0500 Received: from rtp-core-1.cisco.com (rtp-core-1.cisco.com [64.102.124.12]) by rtp-dkim-1.cisco.com (8.12.11/8.12.11) with ESMTP id m07EaBO6016031 for ; Mon, 7 Jan 2008 09:36:11 -0500 Received: from xbh-rtp-201.amer.cisco.com (xbh-rtp-201.cisco.com [64.102.31.12]) by rtp-core-1.cisco.com (8.12.10/8.12.6) with ESMTP id m07Ea2I5023246 for ; Mon, 7 Jan 2008 14:36:11 GMT Received: from xfe-rtp-202.amer.cisco.com ([64.102.31.21]) by xbh-rtp-201.amer.cisco.com with Microsoft SMTPSVC(6.0.3790.1830); Mon, 7 Jan 2008 09:35:59 -0500 Received: from [64.102.38.143] ([64.102.38.143]) by xfe-rtp-202.amer.cisco.com with Microsoft SMTPSVC(6.0.3790.1830); Mon, 7 Jan 2008 09:35:59 -0500 Message-ID: <478238D7.3060304@nc.rr.com> Date: Mon, 07 Jan 2008 09:36:07 -0500 From: Ernest Christley Reply-To: echristley@nc.rr.com User-Agent: Thunderbird 2.0.0.6 (X11/20071022) MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Magic Vapor Cycle Engines References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 07 Jan 2008 14:35:59.0425 (UTC) FILETIME=[9ECD0B10:01C8513A] Authentication-Results: rtp-dkim-1; header.From=echristley@nc.rr.com; dkim=neutral Charlie England wrote: > Hi Thomas, > > If I understand your question, I think the assumptions might be > reversed. My understanding is that any dyno, whether water brake, > prop-loaded (air brake), etc. that uses the scale/lever technique is > actually measuring raw engine torque. If you want to measure the > losses in the gearbox and/or prop, you would measure thrust, convert > to HP & compare to HP calculated from torque/rpm. > If you are proposing measuring the output of a generator, you would be > ignoring the losses in the inefficiency of the generator. That would > be the equivalent of measuring only thrust in the previous example. > > If I'm in error, hopefully someone more knowledgeable will jump in. > > Charlie > > > Thomas Jakits wrote: >> Ooh yes! Pleease! >> thjakits@gmail.com >> >> Thank you very much! >> >> Question to a possible "DIY/cheapo"-dyno: >> I saw various plans/models where one bolts up the >> engine/PSRU/club-prop and measures power via rpm x momentum (via >> bathroomscale/lever). This gives me the overall hp - incl any losses >> from the PSRU and inefficiencies fomr the prop. >> What a about a pure engine-dyno? Drive a waterpump/generator (where >> do I get a cheap 300kw generator??) ??? >> Maybe use a prop bolted directly to the output shaft. That gets around the gearbox losses. A ducted fan would also be a little safer. Maybe Perry can convert his old ducts and fans into a dyno business?