Mailing List lml@lancaironline.net Message #27346
From: <Tubamanflies@aol.com>
Sender: Marvin Kaye <marv@lancaironline.net>
Subject: Fuel flow measurement
Date: Wed, 29 Dec 2004 18:29:41 -0500
To: <lml@lancaironline.net>
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
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