Future Aircraft Concepts for Quieter and More Efficient Travel Validated by X-48C Hybrid-Wing-Body Plane

The experimental hybrid-wing-body subscale aircraft X-48C, which demonstrates technology concepts for cleaner and quieter commercial air travel, completed an eight-month flight research campaign conducted by NASA on April 9. The design was derived from concept studies for commercial aircraft that could be flying within 20 years.

"Very quiet and efficient, the hybrid wing body has shown promise for meeting all of NASA's environmental goals for future aircraft designs," said Fay Collier, manager of NASA's Environmentally Responsible Aviation project.

The scale-model aircraft with a wingspan of about 7 meters and shaped like a manta ray, was designed by The Boeing Co., built by Cranfield Aerospace Limited of the United Kingdom, and flown in partnership with NASA. The X-48C is a version of NASA's X-48B blended wing body aircraft modified to evaluate the low-speed stability and control of a low-noise version of a notional hybrid-wing-body design. This design features a flattened fuselage with no tail, and engines mounted on top of the fuselage at the rear of the plane.

Primary changes to the X-48C model from the B model, which flew 92 flights at Dryden between 2007 and 2010, were geared to transforming it to an airframe noise-shielding configuration. External modifications included relocating the wingtip winglets inboard next to the engines, effectively turning them into twin tails. The rear deck of the aircraft was extended about two feet. Finally, the project team replaced the X-48B's three 50-pound thrust jet engines with two 89-pound thrust engines. The aircraft had an estimated top speed of about 140 mph and a maximum altitude of 10,000 feet.

"Working closely with NASA, we have been privileged throughout X-48 flight-testing to explore and validate what we believe is a significant breakthrough in the science of flight and this has been a tremendous success for Boeing," said Bob Liebeck, a Boeing senior technical fellow and the company's Blended Wing Body (BWB) Program manager. "We have shown a BWB aircraft, which offers the tremendous promise of significantly greater fuel efficiency and reduced noise, can be controlled as effectively as a conventional tube-and-wing aircraft during takeoffs, landings and other low-speed segments of the flight regime."

Because handling qualities of the X-48C changed, the project team modified the flight control system software, enabling a stronger and safer prototype flight control system suitable for future full-scale commercial hybrid or blended wing aircraft.