Question

The propulsive force developed by the engine-propeller combination is given by _______

(a) \(\frac{\eta V}{P}\)

(b) \(\frac{\eta P}{V}\)

(c) \(\frac{P}{V}\)

(d) \(\frac{VP}{\eta}\)

The question was posed to me in an international level competition.

This key question is from Climb and Descent Performance with Power-Producing Engines in section Climb and Descent Performance of Aircraft Performance

Answer 1

Correct choice is (b) \(\frac{\eta P}{V}\)

Easy explanation: The propulsive force developed by the engine-propeller combination is given by \(\frac{\eta P}{V}\) where η is propeller efficiency, P is power and V is velocity. The equation of power-producing engine is written as \(\frac{\eta P}{V}\)-D=Wsinγ2.