Eurocopter X-3

The Eurocopter X³ (X-Cubed) is an experimental high-speed compound helicopter developed by Airbus Helicopters (formerly Eurocopter). A technology demonstration platform for "high-speed, long-range hybrid helicopter" or H³ concept,[1] the X³ achieved 255 knots (472 km/h; 293 mph) in level flight on 7 June 2013, setting an unofficial helicopter speed record.[2][3] In June 2014, it was placed in a French air museum in the village of Saint-Victoret.The X³ demonstrator is based on the Eurocopter AS365 Dauphin[1] helicopter, with the addition of short span wings each fitted with a tractor propeller, having different pitch to counter the torque effect of the main rotor.[1][4][5] Conventional helicopters use tail rotors to counter the torque effect.[6] The tractor propellers are gear driven from the two main turboshaft engines which also drive the five-bladed main rotor system, taken from a Eurocopter EC155.