You are right, gentlemen, having looked into gyroplanes some more it is clear that the rotor head is more complex than I thought. In particular, the Rotodyne type design with tip jets is actually a hybrid, as it acts as a helicopter for landing and taking off. The tip jets were switched off at a forward speed of 60 mph, and after that the rotor autorotated, providing lift just by being spun in the airstream (so it was tilted backwards in flight, not forwards as with a helo).
However, the rotor design is not a reason for criticising the gyrodyne - after all, it is no more complex than that of a helo, and they seem to do OK, even in big sizes (see Mi-26).
The gyrodyne makes an interesting contrast with a tilt-rotor like the V-22. The tilt-rotor has a speed advantage, and also only uses one flight system. It may also be more controllable in the hover but I'm not sure of that. OTOH the gyrodyne has its rotor and propellers each optimised for its particular flight mode, rather than a compromise. And having two separate flight systems makes it much safer, as it can autorotate down if it runs out of power, or land like a plane on its props and wings. Above all, the gyrodyne is technically much simpler to build and operate. Just look at the time it has taken to perfect the V-22, whereas the Rotodyne was a technical success four decades ago - long before computerised flight controls.
Tony Williams: Military gun and ammunition
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