The Cheyenne is an interesting helicopter. I was talking with a retired air force colonel who knew test pilots that flew it. Every test pilot loved it because it flew like a fighter and not a helicopter. It has a rigid rotor system, like the Sikorsky ABC (Advancing Blade Concept) concept demensontrator. Note, both aircraft suffer from significant vibration problems, but the Sikorsky X2 has vibration suppression systems. Second note, this is not the first time Sikorsky has made such a helicopter.
I was told by people involved in this aircraft that it required three people to operate. A pilot, copilot and a guy on throttle. The guy on throttle was busy 100% of the time adjusting the engines that gave it forward propulsion and torque for the main rotors.
The x2 is different in that it has a rigid rotor with a significantly reduced rotor hub size. (The one pictured above is huge).