Mad (Flt) scientist,
Yes understand that drag determination can be achieved by calculating thrust delivered by a prop in level flight. I believe formulas exist that have been established from empirical data for both turboprop and turbojet aircraft.
In attempting to do a quick (and rough) calculation in the aircraft I currently fly could I use:
percentage of maximum torque x percentage of maximum RPM x Rated power (at sea level) to establish the power delivered to the prop at some cruise condition above sea level ?
Then multiply the answer by a assumed prop efficiency of .8 to determine power converted to thrust by the prop?
eg .7 max torque x .8 max rpm x 4000 eshp at sea level = 2240 hp delivered
2240 x .8 prop efficiency = 1792 Hp converted to forward speed.
Would this approach hold for all cruise altitudes?
Last edited by Greedy; 5th May 2011 at 02:36.