A Little Technical Marketing

[Dave_Jackson]

Robbo Jock,

Wouldn't you be better off with your interleaving rotors' highest point being over the fuselage, lowest outboard?

The advancing blades are on the outside and they will be producing most of the lift. This is because the intent is to incorporate features such as; 'Absolutely' Rigid Rotors, Advancing Blade Concept, Active Blade Twist and Reverse Velocity Utilization.

One reason for having higher rotors outboard is to give the lifting surface (rotor disks) a dihedral and, hopefully, this dihedral will contribute to lateral stability.

Your suggestion might be correct and it could certainly be done.
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Gadgetguru,

The gap between coaxial rotors depends upon a number of things. The primary one is the rigidity of the rotors and blades.

An example is Sikorsky's XH-59A ABC. The rotor diameter was 36 feet and the rotor separation (gap) was 30 inches. The minimum allowable tip clearance was 10 inches. As of May 1976, the minimum clearance recorded during flight tests was 14 inches.

That's Nick on the left.