Dave, gyros will need to be actuated out of phase or forces cancel. Otherwise the principle is sound. My question remains why would you want to add this additional complexity to the design of a helo? Additional blades are mechanically much simpler, at the cost of increased hangar space.
The reason i ask is that helos are driven by cost, which reflects on us mortals as $/hour. Introducing additional mechanical componentry increases both the initial outlay and the maintenance cost (inspections even if parts have infinite life). I'm not against the use of gyros, far from it since i believe that significant handling improvements are possible, but preference is to use them sparingly and for good reason.
The only real reason i champion the unpopular view of a mechanical SAS over electromechanical systems like the Honeywell SPZ 7600 is that for a light heli a mechanical system will be less likely to be overlooked. Combine this with the fact that failure is likely to be a progressive reduction in performance by wear and it strikes me as a good engineering soln. It does not allow all the advanced features that a full FBW system would, and naturally i accept that FBW will be the long term winner.
Mart