August 08, 2012
Credit: Photo: Robert Wall
Boeing’s X-48C blended wing body (BWB) unmanned research aircraft flew for the first time from NASA’s Dryden Flight Research Center at Edwards AFB, Calif., on Aug. 7.
The 21-ft.-span vehicle is a rebuilt, twin-engine variant of the original three-engine X-48B test aircraft that completed 92 flights over the desert base between 2007 and 2010. The new Advanced Microturbo engines, each rated at 89 lb. thrust, replace three 50-lb.-thrust JetCat P200 turbojets on the earlier version. At this size the X-48C represents an 8.5% scale model of a 240-ft.-span BWB that Boeing believes could be developed for military tanking or cargo-carrying roles.
Boeing says the X-48C’s first flight began at 7:56 a.m. Pacific Time, and reached an altitude of 5,500 ft. before returning to land 9 min. later. Aside from the engine changes, the modified aircraft’s winglets have been relocated inboard, turning them into tails and providing shielding for noise from the engines. The aft deck also is extended farther back, by around 2 ft., to provide noise shielding below and behind the aircraft.
The increased aerodynamic efficiency of the BWB design, which also is under evaluation by Boeing as part of NASA’s Environmentally Responsible Aviation (ERA) program, has shown the potential for up to 50% lower fuel burn and 40 dB less noise than a similarly sized tube-and-wing aircraft.
Initial flight testing of the X-48B focused on the controllability of the tailless design. Testing of the new version will be performed to see if the revised noise-shielding configuration has any adverse effects on low-speed flight characteristics.