Before revision: The pitching moment coefficient is defined as followsClancy, L.J., Aerodynamics, Section 5.4 where M is the pitching moment, q is the dynamic pressure, S is the planform area, and c is the length of the chord of the airfoil.
After revision: The pitching moment coefficient is defined as followsClancy, L.J., Aerodynamics, Section 5.4 where M is the pitching moment, q is the dynamic pressure, S is the wing area, and c is the length of the chord of the airfoil.