Slowrotor,
I agree that a constant speed propeller (& constant speed engine) is best for an airplane. This is probably because there is the desire to maintain the engine speed at a specific location on its rpm/torque curve. Perhaps gyrocopters (CarterCopter, etc.) benefit from a constant speed propeller as well, for the same reason.
This proposed concept also utilizes a constant speed engine. However, the rpm of the rotor must be variable, to adapt to high-speed flight. The fixed gearing arraignment therefore dictates that the rpm of the propeller must be variable as well. Because we want the rpm of the rotor to decrease as the forward velocity of the craft increases, the rpm of the propeller has to increase.
Graviman,
"Regarding the proposed system, i can see it working only in situations of perfectly balanced torque (ie first time you bank it stops working ). "
Why do you believe that it "stops working"? This proposed concept is different from the wheels of a car 'breaking loose' from the road.
"In your case the servo motor would end up having to introduce/remove quite a lot of energy"
The servomotor does not contribute to the driving of the rotor or propeller. It is only required to overcome a small portion of the friction between the worm and wheel. The majority of the friction is handled by the angle of repose of the worm thread.
Quadrirotor;
WOW. Thanks for mentioning Dick Degraw's Rhinogyro. I looked up the Torsen differential . It also uses the feature of one way power transmission through a worm and wheel.
The results of a preliminary search on the Torsen differential.
Now for some additional studying, so as to better understand the Torsen differential, and then how Dick DeGraw might have applied it to his gyrocopter.
Dave