Hello Hal

I saw your post and just couldnt resist...

Angle of attack has nothing whatsoever to do with the fact that the incidence of the blades are fixed. Angle of attack is by definition the angle between the chordline and the 'relative airflow'. Relative airflow will constantly change with the speed that the blades are flapping as well as the change bought about by the aft tilt of the rotor and the advancing/retreating effects.

Foward flight is only one component of many that combine to give angle of attack

Angle of attack would only be a constant for a rotor if it was in still air and in a vertical descent.

Remember, incidence is fixed. Angle of Attack for an autogyro is constantly changing ( lets face it, it has to or the rotor disc would be unable to allow for lift differential).

Have I re-opened a whole can of worms ? Hee hee

Sean