The AW-609 tiltrotor is one of the most significant worldwide technological aeronautical innovations of the present era. The development of the AW-609 program contributes to advancement of the AgustaWestland technological research and to further strengthen its competitiveness around the world.
Technically, the tiltrotor is an aircraft designed and built to combine the operational versatility of the helicopter (VTOL) and the various advantages (speed and range) of the fixed-wing airplane. The helicopter and the airplane will remain faithful to their present formula for those features that have made them successful: hovering for the first, high-speed for the second. The ability to combine the qualities of both in a single aircraft allows to overcome the limitations of the fixed wing (need of large free spaces for take-off and landing, high distance from airports to city centers, high dead times for passengers) and those of the rotary wing. The solution is an aircraft that allows vertical take-off as well as a range of action and a cruising speed double compared to a helicopter of the same capacity. An intense research and development activity aimed at creating an aircraft capable of taking off and landing vertically while maintaining high performance in terms of cruising speed has been carried out by numerous aeronautical companies over the last 50 years. Different possible solutions for propulsion have been tested and numerous prototypes were made (most of them under the aegis of military programs) which made it possible to evaluate the pro and cons of each solution. The convertiplane configuration, which has proved to be the most effective, the hovering support capacity is guaranteed by rotating the engine nacelle by 90° (including or not the engine itself depending on the chosen architecture) maintaining the wing fixed. The rotors are sized to ensure the best compromise between hovering and flying performance and are larger in diameter than conventional propellers.
In the AW-609 the rotor shaft axis is vertical for flight operations as helicopter. For the horizontal flight the shafts are progressively rotated forward until, having reached the horizontal position, the rotors act as normal propellers. During this conversion process, which takes place within an ideal conversion “corridor” automatically managed by the on-board computers, the lift is progressively transferred from the rotors to the wing. There are no evident changes in altitude or flight characteristics during the conversion, during which the pilot retains full control of the aircraft. The AW-609, whose take-off weight is about 7 tons and whose airframe is made entirely of composite materials, is able to carry out the conversion procedure (from the typical flight profile of the rotary wing to that of the fixed wing and vice versa) in less than a minute. This versatility allows the tiltrotor to fly at a cruising speed and with a range of action double that of a helicopter and, in its standard configuration, at an altitude of about eight thousand meters thanks to a pressurized cabin and an anti-icing system. The AW-609 is equipped with a triple fly-by-wire (FBW) flight control system, that ensuring excellent handling characteristics, provides reduction of the overall weight of the aircraft, safety and simplicity/containment of maintenance costs. All the parameters necessary for the tiltrotor handling are presented on an advanced cockpit equipped with liquid crystal displays. The AW-609 is powered by two Pratt & Whitney PT6C-67A engines capable, at a maximum take-off weight of 7,636 kg, to fly above 500 km/h and with a range of about 1,290 km which increase to over 1,850 with the support of the auxiliary tanks.