Hello again, its been a while. I am still interested in building an autogyro, and have been studying the technical aspects. I have a pretty solid grasp on most of it except for one thing. How the devil does the rotor turn the way it is supposed to? I have seen the drawings of AOA and lift angle, and it makes sense while looking at the illustration, but it just doesn't translate to the real world for me later. I suppose if I actually saw one fly I would get it.

Do I understand correctly that we have a rotorblade, flat bottom airfoil shaped and we will call the leading edge left. Ok I take this blade and mount it to a hub with 3 degrees positive pitch relative to the hub, or I guess relative to 90 degrees from the hub shaft, whichever, you know what I mean. If it was a heli, you would call it 3 degrees positive collective. Now I tilt it backward relative to wind and this thing is supposed to turn toward the leading edges of the blades?!

In my mind I say not a chance, it will windmill backwards, mainly because of the 3 degrees positive blade angle of attack (collective).

I see it like this.. lets say I take an airplane wing from my shop and drive down the hiway at 50 mph. Then I stick the wing out the window, leading edge first. First level, then with a few degrees up angle. Is it supposed to pull forward? No, its going to rip my arm off, and probably break into pieces. If it would pull forward, I could just stick a bunch of them on the side and shut the ignition off and enjoy perpetual motion. If this sounds silly, then how is a rotor blade supposed to pull itself forward while under the same conditions?

The only thing I can think of is some specific condition that must exist in the arrangement of the angles and such, but this doesnt seem so because the autogyro can be flown in different ways, even stunts, which would exclude the possibility for delicate conditions existing. The other thing is maybe that the retreating blade(s) have something to do with producing a driving force.

Someone help me out, I recently started flying helis and this *demands* that I understand autorotation. Thanks.