Eurocopter X3 - World’s Fastest Helicopter

Eurocopter’s X3 hybrid helicopter is the world’s fastest helicopter with the original speed of 220 knots, while most helicopters can fly with maximum speed of 130-140 knots. X3 hybrid is equipped with two turboshaft engines to power five-blade main rotor system and two propellers on short-span fixed wings.

X3 combines the vertical takeoff and landing (VTOL) and hover capabilities of a helicopter with the fast cruise speeds of a turboprop-powered aircraft. 

Via: Gizmag