Eurocopter X3

The Eurocopter X3, written X-Cubed, was an experimental high-speed compound helicopter developed by Airbus Helicopters, then Eurocopter, as a technology demonstrator for its high-speed, long-range hybrid helicopter or H3 concept. It is based on the AS365 Dauphin with short-span wings each carrying a tractor propeller, gear driven from the two main turboshaft engines that also turn a five-bladed rotor taken from the EC155, so no tail rotor is needed to counter torque. The X3 first flew on 6 September 2010 from the Istres-Le Tubé air base and reached 255 knots, about 472 kilometres per hour, in level flight on 7 June 2013, an unofficial helicopter speed record. It was retired and placed in a French air museum in 2014.