Return-Path: Received: from pop3.olsusa.com ([63.150.212.2] verified) by logan.com (CommuniGate Pro SMTP 3.5.1) with ESMTP id 1000243 for rob@logan.com; Tue, 01 Jan 2002 10:12:29 -0500 Received: from out002pub.verizon.net ([206.46.170.102]) by pop3.olsusa.com (Post.Office MTA v3.5.3 release 223 ID# 0-71866U8000L800S0V35) with ESMTP id com for ; Tue, 1 Jan 2002 09:54:17 -0500 Received: from GCasey (calnet31-66.gtecablemodem.com [207.175.254.66]) by out002pub.verizon.net with SMTP for ; id g01EtGd17759 Tue, 1 Jan 2002 08:55:17 -0600 (CST) Reply-To: Reply-To: lancair.list@olsusa.com From: "Gary Casey" To: Subject: BMEP (torque sensing) Date: Tue, 1 Jan 2002 06:53:53 -0800 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Importance: Normal In-Reply-To: <20020101053149.AAA21649@pop3.olsusa.com> X-Mailing-List: lancair.list@olsusa.com <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> >>As an old school A&P can you tell me why the recip transports usually had a BMEP guage which was given its (oil press) signal from the torque nose of the (HamStandard) prop? If it is true BMEP is a mathematical construct, and it is, how and with what error was the Tq given as BMEP? Is it just a piston era relic? Do modern turbine Tq guages have any intrinsic misleading error?<< This repeats a little from the previous excellent post, but it might be worthwhile for its simplicity: As far as I know the torque sensing for the old radial engines and the new turbine engines are essentially the same. Both use planetary gear speed reducers and use the torque reaction of the stationary element to push on a hydraulic cylinder. The pressure is directly proportional to engine torque and is displayed in units that are understandable (psi wouldn't do it). For piston engines BMEP is a number that will translate well between different engines and will correlate to textbook information. For turbines I believe they just display it in percent of rated or something to that effect. There are no inherent errors in this approach, just the normal errors do to friction, tolerances, etc. Gary Casey ES project >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://members.olsusa.com/mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please remember that purchases from the Builders' Bookstore assist with the management of the LML. Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>