"Dave seeks a "balanced, symetrical" rotor as solution to handling issues that have been solved years ago without doing mechanical backflips - by installing a fly-by-wire control system."
Just my two cents worth - feel free to refute (i certainly value the opinion of the ABC T.P. very highly). I see the advantage of intermeshing as primarily being aerodynamic, by avoiding the retreating blade tip stall and reverse flow area. If blade divergence at u>0.5 can be avoided it would be possible to build a helicopter capable of hover, then safe transition into flight up to the limits of either compresibility or at least engine power. The synchropter, if well designed, just has the advantage of reduced drag/power in all flight conditions.
Agreed that fly-by-wire, or even a mechanical gyroscopic derivative cures all the handling quirks on a conventional. Other handling advantages come out of the symmetry, but are not driven by it. As i have freely admitted to Dave, my own interest really comes out my wish to understand the limits of helicopter technology, plus how easily implementable the techniques are in practice. (I tried for a job at Westlands, just as they were about to lay people off
- bad times in the UK)
Mart