Fuel Flow Test (2)

 2 hours

One of the tests I still needed to do was to make sure the gravity fed fuel system would be able to supply enough fuel to run the engine at max power.  The guidelines I read stated that you should ensure the fuel system can supply 150% of the fuel required for max power, so for my 100 hp engine that would be roughly 15 gallons per hour.  It also said that a nose-up attitude is typically the worst case for fuel flow, since the carburetor is higher and the outlet from the tank is lower.

Anyway, I raised the nose as high as I safely could by myself, by jacking up each wheel and putting a ramp underneath.  That got me to 10.7 degrees nose up.  I put 10 gallons in the tank (which was way overkill I realized), disconnected the fuel line at the carb, and opened the valve to drain the fuel back into the gas can.  I timed how long it took, and also kept an eye on the fuel flow readout on the G3X.

I observed that at 10 gallons in the tank, the flow rate was 28.8 GPH, and it gradually decreased as the quantity went down.  At 1 gallon remaining, it was still flowing at 25.4 GPH, and it never went below 24 GPH until the tank was totally empty.  Good enough!!