Question

Which of the following is incorrect for a thin, cambered airfoil?

(a) The angle of attack is small

(b) The induced velocity distribution for the camber line is the same for the chord line

(c) Vortex sheet is kept at the chord line

(d) The slope of the camber line is zero

This question was addressed to me in a job interview.

The query is from The Cambered Airfoil topic in section Incompressible Flow over Airfoils of Aerodynamics

Answer 1

Right answer is (d) The slope of the camber line is zero

Easiest explanation: Slope of the camber line \(\frac {dz}{dx}\) is not zero for a cambered airfoil but is some finite value. All the other statements are valid assumptions of thin airfoil theory.