The X-50A aces critical ground test; validates design

BY DOUG KINNEARD

With its main rotor spinning for the first time, the revolutionary X-50A unmanned vehicle, being developed with breakthrough technology, has passed a critical ground test in Mesa, Ariz.

The X-50A Canard Rotor/Wing prototype, also known as the Dragonfly, is undergoing rotor track and balance testing and has successfully achieved 100 percent rotor spin rates.

"This critical test validates the design, construction and operation of the rotor and paves the way for the next ground test, which will put actual thrust loads on the rotor," said Steve Bass, X-50A program manager.

Rotor testing is the last in a series of systems, vibration, structural, and engine evaluations before first flight, scheduled for this year at Yuma Proving Grounds in Arizona.

The X-50A is a revolutionary concept that combines the vertical takeoff and landing capabilities of a helicopter with the high-subsonic cruise speed and agility of a fixed-wing jet aircraft.

It is so groundbreaking that Bill Lawler, vice present and general manager of Strategic Operations and Planning for Integrated Defense Systems in St. Louis, recently told Frontiers the X-50A, "could produce a military and commercial market.

"It could change the game for the helicopter industry in the same way that the jet engine did for the aircraft industry," he said.

Boeing Phantom Works and the Defense Advanced Research Projects Agency are developing the Canard Rotor/Wing. DARPA entered a 50-50 cost-share agreement with Boeing Phantom Works in June 1998 to further the development and production of two low-cost unmanned demonstrators, designated the X-50A.

The X-50A is 17.7 feet long and 6.5 feet high, has 12-foot-diameter rotor blades, and is powered by a conventional turbofan jet engine. For helicopter flight mode, diverter valves direct engine thrust to nozzles in the rotor blade tips. For fixed-wing cruise, the valves gradually redirect all the thrust to an aft fuselage nozzle and allow the rotor to lock in place and serve as a wing.

According to Bass, directing thrust through the rotor tips eliminates the need for a heavy and complex mechanical drive train, transmission and anti-torque system. The X-50A will be much lighter and simpler than traditional rotorcraft and will therefore be much more affordable to operate and support.

Follow-on CRW versions could evolve into larger manned vehicles capable of conducting specialized missions, including reconnaissance, armed escort, urban operations, tactical air support, communications/data relay and logistics resupply.