Question

The quarter-chord moment coefficient for a cambered airfoil depends on______

(a) Chord length

(b) Angle of attack

(c) The shape of the airfoil

(d) Center of pressure

I have been asked this question by my college professor while I was bunking the class.

My doubt is from The Cambered Airfoil topic in portion Incompressible Flow over Airfoils of Aerodynamics

Answer 1

Right choice is (c) The shape of the airfoil

Explanation: The coefficient of moment about the quarter-chord is independent of angle of attack and chord length. It depends on the shape of the cambered airfoil (slope of the camber line (\(\frac {dz}{dx}\))).