DARPA’s reluctance is obviously due to the high potential of the X2 as an ultra-light personal aircraft threatening the replace the motorcar for intercity travel in the future.

The real break-through achieved with the X2 is its cruising speed of almost twice the classical chopper’s.

This quantum leap has been made possible by generating all the forward thrust with a pusher propeller, allowing for the main rotor to remain horizontal up to highest cruising speeds, thus avoiding most of the wildly savage pitch errors occurring all along the blades at maximum cruising speed with traditional single rotor helicopters.

It is neither DARPA’s nor NASA’s intent to contribute to the development of aircraft that could lead to massive popularization of individual aeromobility. These government agencies have to comply to the most important strategic rule for power enforcement, i.e. to ensure total control of the global airspace by the US Air-Force.

What they fear most is the civilian society challenging this absolute air-superiority by taking possession of the global airspace with myriads of personal aircraft.

That’s why all their research on improving the classical chopper is just a lame duck intended to lure you into the illusion that they are working hard towards more eligibility for popular use of rotary-wing aircraft.