I hate to establish an argument (yea right!) but when you land an autorotation, you go into Powered flight! The concept is that the "power" comes from the rotor inertia, and is applied to make the rotor behave as if the engines were connected. There is no aerodynamic difference between a touchdonw auto in the final landing sequence and a hover touchdown.
If you took a snapshot of the helo at the touchdown phase, you would find the rotor pumping air downward, in mass sufficient enough to develop thrust that is more than the weight of the helicopter (because the rotor is slowing down the vertical speed, and thus accelerating the helo upward). A G meter will read slightly above 1 g when the landing is being accomplished.
Last edited by NickLappos; 22nd Dec 2005 at 19:46.