Question

A cambered airfoil is operating with 200N of lift. The velocity of the flow is 500m/s. Determine lift-induced drag by this camber airfoil.

(a) 0N

(b) 0

(c) 0.5

(d) 0.5

This question was addressed to me during an online interview.

Question is taken from Airfoil Selection-3 in division Airfoil and Geometry Selection of Aircraft Design

Answer 1

The correct answer is (a) 0N

The best explanation: Given, Lift=200N, velocity = 500m/s.

For cambered airfoil the downwash angle = 0°. Hence, there will be no downwash acting on the flow.

Hence, there will be no induced drag. Hence, for any airfoil induced drag = 0N.