Thanks for that ED.   Neil.

Hi Neil,

If not interested in fuel total then attached here is my revised drawing of Tracy's Fuel Flow meter that when calibrated is surprisingly accurate.

If building your own microprocessor to do same, the only thing I can think of you may need to keep in mind is that the fuel flow before staging is only 1/2 (approx) the fuel flow after staging to all 4 injectors.

Ed

-----Original Message----- From: Neil Unger
Sent: Thursday, July 27, 2017 5:11 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: fuel consumption gauge

ED,  Quantity is not really my interest, I am more interested in just
what the engine is using at that time, so I can get best range, plus I
am interested in just how much I am spending at full noise.  Thanks Neil.


On 7/27/2017 8:58 AM, Ed Anderson wrote:

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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