The value of military aircraft with both short takeoff and landing (STOL) and vertical takeoff and landing capabilities (VTOL) was recognized by the United States Department of Defense decades ago, prompting the collaboration between Boeing Helicopters and Bell Helicopter in 1983 to develop a tiltrotor aircraft. Although the resulting CV-22 Osprey took its first flight in 1989, it took many years of design adjustments and flight testing before the tiltrotor aircraft was used in the field by the United States Air Force and United States Marine Corps in 2007. Since then the Osprey has proven to be invaluable both in combat and rescue operations in Afghanistan, Iraq, Sudan and Libya.
Until now tiltrotor aircraft have been restricted to military service, but helicopter manufacturer AgustaWestland hopes to change that with their new AW609 tiltRotor aircraft which recently successfully completed ten flight hours focusing on wind-milling and autorotation – a process where the rotors of the aircraft in helicopter mode turn in response to air movement as the aircraft descends. This feature will assist the AW609 in landing safely in the event of the aircraft’s engines failing completely. Reporting on the test flights of the AW609 prototype, which were monitored by the FAA at a facility in Arlington, Texas, an AgustaWestland spokesperson noted that the aircraft’s performance exceeded expectations based on the engineering simulator.
A second prototype of the AW609 is being tested at facilities in Samarate, Italy. With more than 650 flight hours, the aircraft have demonstrated their ability to cruise at speeds of up to 275 knots at maximum takeoff weight of 16,800 pounds and reach altitudes of 25,000 feet. Currently being assembled, a third prototype will be used for ice testing and certification, while a fourth prototype is planned for the development and integration of the latest avionics.
The Anglo-Italian company is working towards gaining FAA certification for the AW609 in the year 2017. In anticipation of FAA approval, AgustaWestland is reportedly planning manufacturing facilities to fulfill orders it already holds, as well as setting up a full flight simulator for training commercial pilots.
As aviation technology continues to develop at breakneck speed, the goal of producing aircraft with vertical take-off and landing (VTOL) capabilities, that can fly as fast as a fixed-wing airplane may soon become a reality. This has been achieved to some degree with the tiltrotor technology of the Bell-Boeing V-22 Osprey, where lift and propulsion are generated by proprotors mounted on engine pods at the ends of a fixed wing. Take off is facilitated by the rotors being angled horizontally as a helicopter rotor works, but as the aircraft gains speed, the rotors tilt forward until they are vertical, allowing the aircraft to reach higher speeds than a conventional helicopter. An Australian company recently announced that it is developing an aircraft which can transition between VTOL and fixed-wing modes with what it calls StopRotor Technology.
The company’s new RotorWing design reportedly aligns the airflow with rotation axis of the rotor while the aircraft is in flight, thereby creating a stable flight profile allowing the smooth transition from one mode of flight to the other. In a statement announcing the new concept, the company noted that the it is a “paradigm shift involving flight well beyond the limitations of conventional fixed and rotary wing flight”, going on to say that it “requires a new way of thinking”.
A patent application has been lodged for the new StopRotor, and the company is currently using flying models and computer simulations to test the concept, which was inspired by the VTOL X-Plane program announced in February by the US Defense Advanced Research Projects Agency (DARPA). The DARPA VTOL X-Plane project is dedicated to developing VTOL aircraft with greater hover and cruise efficiency, larger payload capacity, and higher speeds than current aircraft – the performance standard being set at greater than 300 knots, which is almost double the speed of the fastest helicopter today. Project leader Ashish Bagai noted that it was hoped that the project would “spark a paradigm shift”. DARPA is putting $150 million into developing the X-Plane which would prove valuable in search and rescue missions, surveillance, transportation of troops and other difficult to reach situations requiring swift response time.