Keith, your quote
“a camered aerofoil produces a nose-down pitching moment when at its zero-lift angle of attack. But at normal (more positive lift-producing) angles of attack it will produce a nose up pitching moment. The greater the angle of attack (up to the stall), the greater will be the nose-up pitching moment.”
Leaves me puzzled. Aerodynamics for Naval aviators pg 50 shows that “section moment coefficient, Cmac to be negative for all examples of cambered airfoils, namely naca 23012, 631-412, 4412, and 23012 with various flap types. And specifically, it is a constant negative value from 0 section lift coefficient Cl up to just before the stall. The sign convention applied to moment coefficients is that the nose-up moment is positive.
Any idea what gives?
Hawk