Geink...

Our good friend, Emilio Cabezas offered an explanation of how an autogyro rotor gets "tilted" when side-to-side or fore-aft inputs are applied. Steve is certainly right that the control inputs don't have to be applied 90 degrees ahead of the desired motion. But what does happen is as follows:

Assume that the rotor has two teetering blades. And that the rotor is spinning counter clockwise as viewed from above. Also consider that the blades are oriented exactly fore and aft. Now, apply tilt input to the left. The blade pointing rearward is twisted to increase its angle of attack and the blade pointing forward is twisted to decrease its angle of attack.

The rearward pointing blade, because it now has a greater angle of attack, is subjected to an upward force. But due to the gyroscopic nature of the spinning rotor, the blade doesn't move upward until it is 90 degrees farther around...namely on the right side of the disk and so the blade moves up and tilts the plane of rotation to the left.

The same argument can be used to explain the tilting of a rotor that has flapping blades.

Hope this is clear!! <G>

Bill