the future A dedicated team advances development of the Blended Wing Body concept By Bill Seil and photos by Bob Ferguson BDuring the Cold War, he designed wings for secret high-altitude airplanes.His doctoral thesis was “Optimization of Airfoils for Maximum Lift.”ob Liebeck has always been fascinated by wings. As a consultant, he has designed wings that boosted performance for racing cars that won Indianapolis 500 and Formula 1 races. He even designed the keel section for the yacht that won the America’s Cup in 1991. Since 1989, much of Liebeck’s time has been devoted to an innovative concept called the Blended Wing Body, an airplane design that lies somewhere between a traditional “tube-and-wing” airplane and a flying wing. Boeing and NASA since 2007 have been conducting flight tests of two unmanned Blended Wing Body prototype airplane designs—the X-48B and X-48C—at NASA’s Dryden Flight Research Center at Edwards Air Force Base in California. The results of the research, undertaken to benefit the aerospace industry as a whole, have been widely disseminated. While Boeing has no plans to develop a Blended Wing Body commercial airplane, knowl- edge gained from these tests will be used to evaluate the potential for future military aircraft. Liebeck, a Senior Technical Fellow in Boeing Research & Technology, now is the company’s chief scientist for Blended Wing Body research. The veteran engineer has won a number of industry awards, including the General Charles E. Yeager Award for Aeronautical Innovation and the Daniel Guggenheim Medal. In addition to his work PHOTOS: (Above) Members of the X-48C at Boeing, he is a professor at the Massachusetts Institute of Technology and the team prepare the aircraft for a test flight University of California at Irvine. from the dry lake bed at NASA’s Dryden He noted that the X-48B made 92 test flights and produced invaluable data. Flight Research Center at Edwards Air “The challenge was to test the flight mechanics of the Blended Wing Body concept Force Base, Calif. From left, Dave Weston, and prove we could maintain stability and control,” Liebeck said. “We thoroughly X-48C safety officer, Phantom Works; Jonathan Vass, X-48C test conductor, addressed these issues with the X-48B and got excellent results.” Boeing Research & Technology; and Ted Testing of the X-48C, which began in August, already is off to a good start. While Rothaupt, X-48C test director, Boeing Re- the X-48B had three engines mounted on top and to the rear of the airplane, the X-48C search & Technology. (Insets, from left) has two engines. The most critical change was removing winglets located on the tips of A decal commemorates the 50th flight, the wings and replacing them with inboard vertical structures near the engines. Tests which occurred with the earlier X-48B model, in April 2009; the X-48C, ready for of the X-48C will determine which configuration is best. another test flight at the Dryden; one of the “We didn’t put the engines on top of the airplane to reduce noise; we had other two X-48C engine nacelles. BOB FERGUSON/BOEING 20 BOEING FRONTIERS / DECEMBER 2012–JANUARY 2013
Frontiers December 2012/January 2013 Issue
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