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The program was canceled before the aircraft had attempted any flights with the rotor system. The Boeing X-50 Dragonfly had a two-bladed rotor driven by the engine for takeoff. In horizontal flight the rotor stopped to act like a wing. Fixed canard and tail surfaces provided lift during transition, and also stability and control in forward ...
The Boeing X-50A Dragonfly, formerly known as the Canard Rotor/Wing Demonstrator, was a VTOL rotor wing experimental unmanned aerial vehicle that was developed by Boeing and DARPA to demonstrate the principle that a helicopter's rotor could be stopped in flight and act as a fixed wing, enabling it to transition between fixed-wing and rotary-wing flight.
A tiltrotor is an aircraft that generates lift and propulsion by way of one or more powered rotors (sometimes called proprotors) mounted on rotating shafts or nacelles usually at the ends of a fixed wing. Almost all tiltrotors use a transverse rotor design, with a few exceptions that use other multirotor layouts.
A rotor wing aircraft has been attempted but is not in wide use. The Boeing X-50 Dragonfly had a two-bladed rotor driven by the engine for takeoff. In horizontal flight the rotor stopped to act like a wing. Fixed canard and tail surfaces provided lift during transition, and also stability and control in forward flight. Both examples of this ...
In 2012, the FAA stated that the AW609 was to be certified in compliance with both helicopter and fixed-wing aircraft rules. New codes were to be developed to cover the transition phase between the two modes. [46] Of the 217 Pilot Training Tasks, 10 are unique tiltrotor tasks. [47]
In the Bell design, Bell Model 301, the whole wingtip pod rotated between horizontal and vertical, with the engine and rotor assembly fixed together within the pod. This simplified the power transmission, but it had more complicated requirements for the engine design and was probably slightly heavier than the Boeing proposal.
Another advantage of tiltwing aircraft is the ease of transition between VTOL and horizontal flight modes. A tiltrotor must first fly forwards like a helicopter, building airspeed until wing lift is sufficient to allow the nacelles to begin tilting down. As a note, the MV-22 Osprey's stall speed in airplane mode is 110 knots (204 km/h; 127 mph).
Inflight transition from fixed to rotary mode was demonstrated in August 2013. [10] [11] [12] Another approach proposes a tailsitter configuration in which the lifting surfaces act as a rotors during takeoff, the craft tilts over for horizontal flight and the rotor stops to act as a fixed wing. [13]