# Calculating Propulsive Efficiency Given Prop Diameter, Velocity, Thrust, and Altitude

An aircraft is flying straight and level at a speed of 150 mph. Its propeller has a diameter of 8 ft and is generating 300 lbf of thrust at an altitude of 3000 ft. What is the propulsive efficiency of the propeller at this operating point?

no equations given, but from searching around Ive found that Propulsive efficiency = (thrust *velocty)/ power

Intuitively, Ive tried several ways to calculate power with the given variables, but all of my answers come out to an efficiency much greater than 1, which, of course, is impossible.