Hmmm, complexity for no gain - bad idea. Stick to 3-rotor with CVJ+HS for effective hinge offset with no vibration, Dave.
This is the one instance where an interleaver scores highly. Both rotors may be teetering, while maintaining very positve roll authority. Pitch TPP angle would just help rotor to provide efficient forward thrust at high speed. It all falls down, of course, since the span of the aircraft for a given disk loading wipes out any weight advantage of not transferring rotor hub manouvreing torque on a single large rotor...
Nick, what was the construction of the Comanche hub? After seeing either you, or Bill Fell, doing unbelievable roll rates on Discovery Channel, i did some googling. I gather the construction was composite torque tubes, with hingless bearings? Is that using elastomeric feathering bushes then?
Mart