From: "Ed Anderson" <flyrotary@lancaironline.net>
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To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] fuel consumption gauge
Date: Wed, 26 Jul 2017 18:58:43 -0400
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Tracy had such a function in his EM system and I had one in the EFISM I once 
sold.  Both calculated the fuel flow (and quantity used) based on the 
duration of the injector pulses.  The flow rate was basically the 
instantaneous pulse duration, while integration of the pulse durations over 
some time period gave you the total fuel used.

Since electronic injectors are essentially constant flow devices (at any 
constant fuel pressure) , if you know how long its open then you can 
calculate the two factors.  It could be very accurate.  And of course 
measuring millisecond pulses with a microcontroller that measures down to 
microseconds, you can understand why the results were so good.

Tracy also came up with a quite simple and suprisingly accurate fuel flow 
indicator using basically a capacitor and LCD meter.  With the correct 
capacitance, the amount of voltage that the pulse could charge the capacitor 
could be read out on the LCD meter as gallons/hour flow.  I built several 
and was surprised at how accurate they could be once calibrated.  But, they 
did not provide quantity which is apparently your interest.


Ed

-----Original Message----- 
From: Neil Unger
Sent: Wednesday, July 26, 2017 5:58 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] fuel consumption gauge

Gents,  Is anyone aware of a fuel consumption  gauge that will give fuel
consumption in real time?  I can get one that has two flow meters but
that makes installation complicated and not really cost effective.  I am
looking for something that works off the injectors.  As usual it has to
be "tweaked" with actual fuel usage.  Did not Tracy have such a system?
Neil.


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