Fuel flow "red cube" and "flowscan" options gone

[cujet]

Hi there!

This past summer, I installed a SV system and selected option other than the "red cube". It seemed to work fine.

After replacement of the Dynon SV, the option is not there, so I set the unit for 29,600 pulses per gallon (I believe I have the number correct). Clearly, that's not working out properly. As it shows 11 or 12 GPH when it should show 15. And, about 22 at full throttle instead of 30.

Is there another number that flowscan provides? Maybe my paperwork was in error?

 

[dynonsupport]

Per the SkyView System Installation Guide, Revision J, Page 7-31:

The approximate pulses/gallon setting for the Floscan 201B (i.e., cast metal case sensor) is 28,000 to 31,000. The approximate pulses/gallon for the Electronics International FT-60 (i.e., the red cube) is 68,000. You must configure the fuel flow sensor using this numerical value in the Sensor Setup Menu (SETUP MENU > EMS SETUP > SENSOR SETUP).

So, if the fuel flow sensor that you have installed is a Floscan 201B, the number is 28,000 - 31,000 (typically, the correct value is attached to a tag on the sensor). If the fuel flow sensor that you have installed is an EI FT-60 (Red Cube), the number is 68,000. Both of these values require adjustment, and that procedure is explained in the SkyView System Installation Guide.

 

[cujet]

OK, thanks that makes sense.

I'll come up with some other way to calibrate the unit. Probably the beaker and stopwatch method. Using simple trial and error and some high tech reverse calculations . I'm sure it will be close enough.

 

[dynonsupport]

The best way to calibrate a fuel flow sensor is with the procedure in the manual, which is to fly 50-100 gallons of fuel (as measured by the fuel pump) and then look at how much the fuel computer said you used. This will give you the adjustment factor you should enter. The math to do this is simple and is in the install manual. You could probably even get away with 10 gallons or so for your first rough adjustment.

The issue with pouring fuel into a beaker is that it flows a LOT faster than it does when the engine burns it, and this can throw off the readings. It will get you close, but it could still be off by 10%, where the known-burn method gives you calibrated flow within the band of flow rates that the engine actually uses.

You don't actually need to calibrate the rate of the flow sensor. It has a certain number of pulses per gallon, so all it actually measures is total volume, and the fuel computer looks at volume vs time to figure out rate.