Another thing to throw into the mix - a fixed wing in a fully developed spin is in autorotation - after the stall and subsequent prospin control inputs a considerable amount of height is lost until stable autorotation is established. GAGS E86
It's a different sort of autorotation, eagle. You are right, it takes a few turns to get steady state, to where you can let go of the controls and the aircraft spins in a predictable fashion, and stay that way until impact if no spin recovery inputs are made. In that case, the entire aircraft is rotating about the vertical axis ... you sort of create a rotating wing out of the wings and fuselage ... is that the point you are making?
I've taught spins in FW, and autorotations in helicopters, and I'd never take the position that they are the same sort of maneuver. Not sure what you are after there.
A helicopter autorotation is a different critter from a spin. The rotating wings are not stalled during the evolution, and the rest of the aircraft, once the torque is reduced/removed by reducing pitch, doesn't flop about. You remain in controlled flight.
About autorotations to check control rigging:
I agree that it takes some altitude to establish a steady state auto, steady state ROD, and your test airspeed right on the money to take the precise data point needed to check control rigging. I think it's a bit much to use such a requirement to assert that you aren't in a stable auto in less than a thousand feet. Depending on rotor inertia, you can get stable enough in light helicopters to make a complete auto in less altitude. In the big and heavy ones, maybe not ... haven't done on in a while, so I'll not go any further on that score.
eagle, I very much liked the list of cases you provided for reference, since engine out and auto fit into a lot of different conditions, and one needs to be prepared for any of them.
Great thread, by the way.
Thanks to all who have contributed.