Is Sikorsky’s X2 a true helicopter?

Questions are being asked on the other side of the Atlantic on whether Sikorsky’s X2 is a helicopter or a compound aircraft.

Elfan Ap Rees, the editor of Helicopter International magazine in Great Britain, objected to Sikorsky’s claim that the X2 is unofficially the fastest helicopter in the world after clocking 235kts.

Geoff Russell, a spokesman for AgustaWestland, added that the X2 does not qualify as a “pure helicopter” because its thrust does not come purely from the main rotor.