Note also that autogyro analogies are likely to be misleading because the vertically oriented turbine in an autogyro . . .
You mean the propeller, right? The propellor is vertical; the unpowered rotor is horizontal.
. . . does no work on the plane -- a craft in level flight needs no energy to stay up. All it needs energy for is to overcome drag.
Well of course it needs energy to stay up! I don't get this statement. The energy needed to stay up comes from the forward motion spinning the unpowered horizontal rotor.
Note that the turbines in the skywindpower gadget are horizontal, like autogyro rotors. (They look horizontal to me.) The wind turns them the same way it turns the unpowered horizontal rotor in the autogyro.
- Jed
