Researchers believe it will have greater fuel efficiency because more of the plane produces lift. More lift is gained because the wing centerbody, which on a blended wing body replaces the fuselage of a conventional airplane where the payload is carried, is generating lift and minimizing drag.

Scientists from Boeing Phantom Works, NASA, and Air Force Research Laboratory are collaborating on the unmanned research aircraft to explore and validate the structural, aerodynamic and operational advantages of the blended wing body concept.

"One big difference between this airplane and the traditional tube and wing aircraft is that, instead of a conventional tail, the blended wing body relies solely on multiple control surfaces on the wing for stability and control," said Dan Vicroy, senior NASA research engineer.

The Air Force is interested in the technology for potential future military applications, and has designated two, high-fidelity, 21-foot wingspan prototypes as X-48B test vehicles.

"The blended wing body-type technology can cost effectively fill many roles required by the Air Force," said U.S. Air Force 2nd Lt. Scott Vanhoogen, X-48B program manager in the Air Force Research Laboratory Air Vehicles Directorate at Wright-Patterson Air Force Base.

"In an era of rising gas prices and economic constraints, a more efficient plane that can perform the same missions as current aircraft, could allow for greater operational flexibility," Vanhoogen noted. "We are very interested in the upcoming flight tests."

Made primarily of advanced lightweight composite materials, the prototypes weigh about 400 pounds and are powered by three turbojet engines. The vehicles will be capable of low-speed, low-altitude test flights up to 138 mph and as high as 10,000 feet.

Both prototypes were built by Cranfield Aerospace, United Kingdom, in accordance with Boeing's specifications.

In mid-May, the research team successfully completed 250 hours of wind tunnel tests on the X-48B Ship No. 1, at the historic Langley Full Scale Wind Tunnel at NASA's Langley Research Center, Langley Air Force Base, Va.

The prototype has been shipped to NASA's Dryden Flight Research Center at Edwards Air Force Base, Calif., where it will serve as a backup to Ship No. 2, which will be used for planned remotely piloted flight tests at Edwards.

Both phases of testing are geared to learn more about the low-speed flight-control characteristics of the blended wing body concept.

"The X-48B prototypes have been dynamically scaled to represent a much larger aircraft and are being used to demonstrate that a blended wing body is as controllable and safe during takeoff, approach, and landing as a conventional military transport airplane," said Norm Princen, Boeing Phantom Works chief engineer for the X-48B program.

Joseph Lusczek, technical director of Aerospace Systems Design and Analysis, Capability Planning Directorate, Aeronautical Systems Center at Wright-Patterson Air Force Base, has been following the Boeing blended wing body development work since 1995.

According to Lusczek, the blended wing body concept has considerable potential and could have application to future Air Force systems.

"The efficient design would have applicability to transport, tanker, bomber, surveillance and other types of aircraft requiring long range and large payload capacities," he explained. "The concept also could have application to small, unmanned vehicles as demonstrated by the test prototypes."

The Aeronautical Systems Center has performed aircraft design studies using the concept for potential tanker, cargo, and long-range strike missions.

"Boeing has conducted studies showing a blended wing body aircraft would be about 80 percent of the gross weight of a conventional aircraft designed to perform the same mission," Lusczek said. "The aerodynamic efficiency of the concept, uniformly distributing the lift over the total span of the aircraft including a lifting fuselage, requires about 30 percent less fuel to accomplish the mission."

The Boeing, NASA and Air Force Research Laboratory cooperative agreement on the X-48B program culminates years of blended wing body research by NASA and Boeing.

"Those associated with the evolution of the concept are to be commended for their innovation, engineering excellence and foresight," said Lusczek. "It has been rewarding watching this revolutionary concept develop. It's a new plateau in airplane design and has the potential to be the 'shape of the future' for aircraft."

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