Question

What is the relation between climb rate and power speed?

(a) Climb rate increases at minimum power drag

(b) Climb rate decreases at minimum power drag

(c) Climb rate is independent of minimum power drag

(d) Climb rate increases at maximum power drag

The question was posed to me in an internship interview.

This interesting 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 (a) Climb rate increases at minimum power drag

To elaborate: Climb rate is maximum at minimum power drag. The rate of climb is given by [ηP-DV]\(\frac{1}{W}\)=\(\frac{dH}{dt}\) where η is propeller efficiency, P is power, V is velocity, D is drag and W is weight and dH/dt is vertical velocity.