Most helicopters have a top speed of 130 or 140 knots, which works out to about 160 mph. With the seemingly simple addition of two turboprops mounted on little wings, the Eurocopter X3 prototype hybrid helicopter has managed to make it to 267 mph in stable, level flight.
Equipped with two turboshaft engines powering a five-blade main rotor system and two propellers on short-span fixed wings, the X3 demonstrator combines the vertical takeoff and landing (VTOL) and hover capabilities of a helicopter with the fast cruise speeds of a turboprop-powered aircraft.
The company envisions the X3 being utilized in a wide range of applications, including long-distance search and rescue (SAR) missions, coast guard duties, border patrol missions, passenger transport and inter-city shuttle services. It also says the aircraft could be tailored for military applications such as special forces operations, troop transport, combat SAR and medical evacuation.