CTR From United States of America, joined Jul 2005, 303 posts, RR: 0 Reply 2, posted (7 years 4 months 3 weeks 6 days 22 hours ago) and read 6332 times:
Sikorsky's X-2 coaxial rotor is very different than a Kamov.
The X-2 is an evolution of the Sikorsky ABC (Advancing Blade Concept) demonstrator from 20 years ago and uses a rigid rotor without any lead-lag hinges or gimbles. A rigid rotor puts an incredible amount of load into the rotor mast. The ABC demonstrator had many problems (aside from crashing) including instability, minimum payload and excessive fuel consumption. Based on the ABC performance compared to the XV-15 tiltrotor, DOD decided to go with the JVX which became the V-22 tiltrotor.
Sikorsky is using fly-by-wire controls, composites and advances in aerodynamics in the X-2 to solve the ABC problems. I hope they are successful. But I don't believe however that the X-2 will be any less complex than a tiltrotor.