WingedFrog
Well Known Member
Yesterday on a 1.5 hour cross country flight, I experienced several High Fuel Flow alarms in the 10 Gal/h range. I wanted to share this through the Savyanalysis diagram below.
Note that I am observing a 2 Gal/h fuel flow with engine off but electric fuel pump on. This correspond to the fuel return I guess.
Note also (on the diagram) the high fuel pressure I mentioned in another post. It is due to the new Rotax pump plus the electric pump bringing me to the top range of Rotax acceptable fuel pressure
Last, you will note a correlation between density altitude and Fuel Flow which I cannot explain.
I have not adjusted the k factor for computed fuel usage and I obviously get way too high computed fuel consumption with already 2 Gal/h on top of whatever the engine burns.
Overall on this flight the fuel burn averaged 5 gal/h while the computed fuel burn would average about 60% more. I hope that increasing the k factor by 60% will improve the accuracy of my computed fuel burn. Should I change the fuel flow ranges (yellow-green-red) accordingly to avoid these pesky fuel flow alarms or will the k adjustement solve this problem?
Savyanalysis diagram (zoom on the diagram to get more details):
https://docs.google.com/document/d/1rl7MmQiIkkwIF4OCKY_nLdWx_Flk4r_Pou71YwUtENs/edit?usp=sharing
Note that I am observing a 2 Gal/h fuel flow with engine off but electric fuel pump on. This correspond to the fuel return I guess.
Note also (on the diagram) the high fuel pressure I mentioned in another post. It is due to the new Rotax pump plus the electric pump bringing me to the top range of Rotax acceptable fuel pressure
Last, you will note a correlation between density altitude and Fuel Flow which I cannot explain.
I have not adjusted the k factor for computed fuel usage and I obviously get way too high computed fuel consumption with already 2 Gal/h on top of whatever the engine burns.
Overall on this flight the fuel burn averaged 5 gal/h while the computed fuel burn would average about 60% more. I hope that increasing the k factor by 60% will improve the accuracy of my computed fuel burn. Should I change the fuel flow ranges (yellow-green-red) accordingly to avoid these pesky fuel flow alarms or will the k adjustement solve this problem?
Savyanalysis diagram (zoom on the diagram to get more details):
https://docs.google.com/document/d/1rl7MmQiIkkwIF4OCKY_nLdWx_Flk4r_Pou71YwUtENs/edit?usp=sharing
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