NASA’s remotely piloted X-48C hybrid-wing-body subscale aircraft, has completed an eight-month flight research campaign
The aircraft shaped like a manta ray, was designed by Boeing and built using composite materials by Cranfield Aerospace in the United Kingdom. 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. The design originates from concept studies for commercial aircraft that could be flying within the next 20 years.
The X-48C retained most dimensions of the B model, with a wingspan slightly longer than 20 feet and a weight of about 500 pounds. 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.
Bob Liebeck, a Boeing senior technical fellow and the company’s Blended Wing Body (BWB) Program manager said;
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, 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 were different from those of the X-48B, the project team modified the flight control system software, including flight control limiters to keep the airplane flying within a safe flight envelope. This enabled a stronger and safer prototype flight control system suitable for future full-scale commercial hybrid or blended wing aircraft.