Question

The lift curve slope is inversely proportional to thickness and directly proportional to aspect ratio.

(a) True

(b) False

I got this question during a job interview.

My question comes from Lift Force in chapter Aircraft Force Systems and the Equations of Motion of Aircraft Performance

Answer 1

Correct answer is (b) False

The explanation is: The lift curve slope is directly proportional to thickness and inversely proportional to aspect ratio. The lift slope curve is given by \(\frac{dC_l}{d\alpha}\). The theoretical value of lift curve slope of a flat airfoil is 2π per radian i.e. \(\frac{dC_l}{d\alpha}\)=0.