Hiker, you are correct to say that most windmills have positive pitch. However, it is the angle of attack that matters i.e. not the pitch angle. (Remember that the pitch angle is controlled by the pilot but the angle of attack depends on the Relative Airflow). As far as I am aware, no rotary wing aircraft has a negative pitch angle in flight as this would result in a major rotor overspeed (and a nil-wing aircraft). I say "in flight" as I believe that the Lynx has a negative pitch capability to hold it onto the ship's deck (prepared to stand corrected on this). Told you it wasn't easy to explain
