Flight testing of the Lockheed Martin Skunk Works morphing unmanned air vehicle is being held up awaiting approval from the US Federal Aviation Administration to fly the radio-controlled subscale model. Repaired after being damaged in high-speed taxi tests in October last year, the jet-powered UAV has been ready to fly for two months, says Dr Terry Weisshaar, morphing aircraft systems programme manger at the US Defense Advanced Research Projects Agency (DARPA).
Since January, Weisshaar says, FAA approval has been required to fly a remotely controlled aircraft above 400ft (120m). Lockheed needs approval following its decision to relocate testing of the morphing UAV from the dry lake bed at NASA Dryden to a general aviation airport near its Palmdale, California plant.
NextGen Aeronautics, meanwhile, is completing a small radio-controlled model of its competing morphing UAV design. The two companies are working on Phase 2 of DARPA’s morphing aircraft structures programme, under which they are building full-scale windtunnel models as well as the subscale flying models.
Lockheed’s design morphs by folding the wings upwards and inwards to reduce area and increase sweep for a high-speed dash. NextGen’s uses a movable scissors structure, covered with a flexible silicone skin reinforced with metal mesh, enabling its wing to reduce in area as it is swept back. Windtunnel testing of both wings up to a simulated Mach 0.85 and 50,000ft will begin in mid-August.
Weisshaar expects both radio-control models to get airborne within the next month, “just in time” before the Phase 2 programme ends in October.
“The results will be timely,” he says. DARPA plans to select one of the two morphing UAV designs for full-scale flight testing during a yet-to-be-funded third phase.
GRAHAM WARWICK /WASHINGTON DC
Source: Flight International
