Return-Path: Sender: "Marvin Kaye" To: lml@lancaironline.net Date: Wed, 29 Dec 2004 18:29:41 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m16.mx.aol.com ([64.12.138.206] verified) by logan.com (CommuniGate Pro SMTP 4.2.5) with ESMTP id 583269 for lml@lancaironline.net; Wed, 29 Dec 2004 10:21:51 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.138.206; envelope-from=Tubamanflies@aol.com Received: from Tubamanflies@aol.com by imo-m16.mx.aol.com (mail_out_v37_r3.8.) id q.9f.554f1d39 (4552) for ; Wed, 29 Dec 2004 10:21:16 -0500 (EST) From: Tubamanflies@aol.com X-Original-Message-ID: <9f.554f1d39.2f04256c@aol.com> X-Original-Date: Wed, 29 Dec 2004 10:21:16 EST Subject: Fuel flow measurement X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_9f.554f1d39.2f04256c_boundary" X-Mailer: 8.0 for Windows sub 6811 --part1_9f.554f1d39.2f04256c_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Measuring fuel flow and the low rates we use in out Lancairs is difficult at best. The systems that I have looked at that put the flow sensor between the throttle body and the spider are just pressure sensors. By measuring the pressure going to the inlet of the injector they assume the outlet pressure, manifold pressure, is constant. Because the manifold pressure is not constant, indicated fuel flow will change with manifold pressure, The change will be small but there will be a change. I don't know if the newer display systems that take in all the data and then displays it corrects the fuel flow for changes in manifold. Also I have only looked at a couple of systems. There may be some that give a true flow reading. Ray Gardner LNC2@CWF --part1_9f.554f1d39.2f04256c_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Measuring fuel flow and the low rat= es we use in out Lancairs is difficult at best.  The systems that I hav= e looked at that put the flow sensor between the throttle body and the spide= r are just pressure sensors.  By measuring the pressure going to the in= let of the injector they assume the outlet pressure, manifold pressure, = ; is constant.   Because the manifold pressure is not constant, in= dicated fuel flow will change with manifold pressure,  The change will=20= be small but there will be a change. 

I don't know if the newer display systems that take in all the data and then= displays it corrects the fuel flow for changes in manifold.  Also I ha= ve only looked at a couple of systems.  There may be some that give a t= rue flow reading.

Ray Gardner
LNC2@CWF --part1_9f.554f1d39.2f04256c_boundary--