Boeing Phantom Works is completing the second X-50A Dragonfly canard rotor/wing (CRW) technology demonstrator, although an investigation has yet to determine why the first of the unmanned vehicles pitched down and crashed during a hover test (Flight International, 30 March-5 April), writes Graham Warwick.

The second vehicle will be ready to fly late in the third quarter, but is likely to be used first for extensive ground testing of any fixes, says Mike Heinz, general manager of the Phantom Works' Integrated Defense Advanced Systems unit.

"We are doing a lot of CFD [computational fluid dynamics], modelling and simulation" to determine the cause of the crash, which happened during the X-50A's third flight, says Heinz. "It is a very complex environment. There is the rotor-fuselage interaction, and it was in ground effect. We have yet to determine the fundamental flow phenomenon that caused the pitch-down moment." A mechanical failure has not been ruled out.

Boeing remains committed to the CRW high-speed rotorcraft concept, which Heinz sees as complementary to the A160 Hummingbird long-endurance unmanned helicopter programme the company recently acquired from Frontier Systems. "It's a fairly potent portfolio - the CRW combines vertical operations and speed, while the A160 combines vertical operations and persistence," he says.

The Phantom Works is now in talks with the US Defense Advanced Research Projects Agency (DARPA) to ensure funding is available to complete the X-50A test programme, set to culminate in two conversions between rotary- and fixed-wing flight, using the second vehicle. DARPA is also funding the A160 flight-test programme, which Heinz says has shown that its optimum-speed rotor technology is viable.

Source: Flight International