vtol_guy:

First, please note I have changed your name back. With the amount of thought you've obviously put into this thing there is a possibility, granted it's extremely remote, that it might survive its first ascent to the lofty altitude of six inches. Haw.

Twinman George has a good thought about a gyro on the throttles, but I still don't think the engines will respond either accurately enough, or quickly enough.

But when you said you'd gear one, for reversed rotation, don't. Gear both of them, roughly 5:1 ratio, that will get you down to an RPM where you can use heli rotor heads. Set them up with collective pitch only with your gyro controlling roll through variation of the pitch. Or for good maneuverability in a hover use cyclic control as well, couple a second gyro to control airframe pitch through fore and aft cyclic.

You could use a simple gyro for roll, have it in the aileron circuit, but if you left the pitch gyro working in forward flight you might get some nasty resonant vibrations from the uneven blade pitch in the top and bottom of the arc. Best would be the ability to switch them both off, could couple them to the rotor tilt control. Assume you are planning on the "Osprey V-22" basic layout.

But still, without a cross drive system you are almost guaranteed destruction of the airplane. Sooner or later you WILL lose an engine. With full rotor pitch control, and an "Auto rotate" clutch you'd have a lot better chance of survival, but a cross drive is the thing that gives the best chance of avoiding a mad roll into the ground when one engine quits. It would let either engine drive both rotors.

Final note. Again, meaning for this post only. Haw. Why not, if using a cross drive, put the engine or engines inside the fuselage? Granted, you'd have to use a cooling fan, but consider the good points. You'd only need one heavy reduction box, the heavy bits [engine(s) and reduction box] would be closer to the center of gravity giving faster control response, the rotor tilt servo would have a lot less weight to swing, so forth and so on. this would also give you a lot of room in the "Nacelles" for the pitch control servos.

Build your own Osprey plane?
. The engineering, what a pain!

Bill.