Question

The moment coefficient for a thin cambered airfoil about the leading edge is given by______

(a) cm,le=-0.5π(2A0+A1)

(b) cm,le=-π(A0+A1+A2)

(c) cm,le=-0.5π(A0+A1-0.5A2)

(d) cm,le=-π(2A2+A1)

This question was posed to me in exam.

This intriguing question comes from The Cambered Airfoil topic in chapter Incompressible Flow over Airfoils of Aerodynamics

Answer 1

Correct choice is (c) cm,le=-0.5π(A0+A1-0.5A2)

To explain I would say: The moment coefficient for a thin, cambered airfoil about the leading edge is given by cm,le=-0.5π(A0+A1-0.5A2). We can verify that for a symmetric airfoil A1 and A2 are both zero giving the moment coefficient about the leading edge for a symmetrical airfoil, which is not satisfied by other options.