In the 1980s, Bell and Boeing Helicopters began developing a twin-turbo shaft military tilt rotor aircraft called the V22 Osprey. Bell then teamed with AgustaWestland to develop a commercial version known as the BA609 and it achieved its first flight in March 2003. During this time the helicopter industry was excited about VTOL aircraft reaching higher speeds. However, Eurocopter was quiet about its plans only saying it had no plans to develop a tilt-rotor aircraft.
On September 6, Eurocopter began test flights of its high-speed, long-range hybrid helicopter concept, which combines vertical takeoff and landing capabilities with fast cruise speeds of more than 220 knots. Called the X3, it is equipped with two turbo shaft engines that power a five-blade main rotor system and two propellers installed on short-span fixed wings. The engines are RTM322s, which power the company’s NH90 military transport. The main rotor gear box is a derivative of the yet-to-be certified EC175 medium size twin helicopter with a modification of two output drives for the propellers.
In cruise flight the rotor pitch is reduced to provide minimal drag and the small wings provide lift. Thrust comes from the propellers. There is no tail rotor so yaw and anti-torque are controlled by a standard pedal configuration that varies the thrust on each propeller separately. The aircraft can be flown like a traditional helicopter until 80 knots, then the main rotor pitch is reduced as the propeller thrust is increased.
According to Eurocopter, the hybrid aircraft will cost about 25 percent more per hour to operate than a conventional helicopter. However, with the increased speed the company points out that when measured in a per passenger/mile basis the operating costs will drop 20 percent. The X3 is currently a technology demonstrator, but Eurocopter says the concepts could be ready for production models in less than a decade.