Mart,
In IFMU's article it says;
Grant emphasized that the X2 is a demonstrator for a “suite of technologies” that might have applications for future-design civilian and military rotorcraft, but it was unlikely that the twin coaxial main rotor system could be applied to smaller aircraft with smaller rotors due to its rigidity and resultant weight. “You’re probably not going to see these applications in the 3,000-pound weight class,” he said. “This [6,500 pounds] is around the size we would want to be the book end for the low end of the weight class. It is a lot easier to go big.”
You mention;
I think keeping the cost and weight of the machine down is more important.
Why does Sikorsky feel that 6,500 pounds is the lower end for ABC helicopters? There does not appear to be any technical reason for this remark. Perhaps, Sikorsky has no interest in them,
or in other companies, building ABC helicopters with less than 6 seats.
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Rieseler's means of producing
'Absolutely' Rigid Rotors by using aerodynamically balanced pitch instead of aerodynamically balanced flap is ingenious.
I'm going to look into it further, since it might be a logical step toward the UniCopter's and the Nemesis'
Advancing Blade Concept. It will be posted as a separate topic on a new thread from this X2 thread if it continues to look good.
Dave