In flight mechanics, “propeller efficiency” refers to the measure of how effectively a propeller converts the engine power into useful thrust to propel an aircraft forward. It quantifies the efficiency of the propeller in converting rotational mechanical power from the engine into forward motion.
T = Thrust produced by the propeller (force in Newtons or pounds-force) V∞ = Freestream velocity or the velocity of the aircraft through the air (velocity in meters per second or feet per second) BHP = Brake horsepower of the engine (power in watts or horsepower)