"My wish that the two intermeshing rotors could provide gyro stability was an attempt to get a free benefit from the rotors without having to add gismos."
Believe me i really do understand this. My understanding of the problem is that no helicopter could be designed for hands off hover, unless it became aerodynamically impractical. The various four rotor aero-jeeps of the '60s came closest, but you are only considering two - this always leaves one unstable degree of freedom. An absolutely rigid rotor with seriously impractical cone angle may do the trick, but at a cost of weight and hub complexity (or needs a tip tension ring
).
It is your project, but trust me hover control is the greatest impediment to wider rotorcraft appeal - try it if you don't believe me! The gyro system can be easilly designed into the swash plate of a single rotor design, and i honestly don't understand why it has not become a standard light heli feature - but then neither have rigids/articulated. A twin rotor could either use a common gyro, or one on each hub.
For high speed work, i am convinced that the intermesher config is (theoretically) unbeatable for a given engine power. But this has to be outboard advancing and feathered retreating, ideally with pusher prop to keep constant trim, for serious aerodynamic gains. Less than high speed sees fewer, if any, advantage for intermeshing (especially when comparing gyro-aug machines) - i'm with Nick on that one. If you are serious about IRAT control, i don't understand why a proven gyro stabiliser ups the stakes so much. The control system needs development, so you start with a lower spec intermeshing project...
Mart