> I need some additional help with your logic for using clock time for your GPH calculation.
I guess it depends on what you're trying to figure out. If you want to know how many gallons per hour the engine burns in cruise, you have to use real hours. If you're trying to come up with a rough estimate of how much fuel you've consumed from engine start till now, I guess tach time would be a better measure. I'm not sure how you would do flight planning if you were using tach time to calculate fuel burn, though, because it doesn't take headwinds and such into consideration. BTW, I think I said that C85 tachs are calibrated to read hours 1 for 1 at 2500 RPM. I should have said 2300 RPM. John Cooper Skyport Services 518 797-3064 www.skyportservices.net
