Robert H. Liebeck Delivers AIAA 2016 Dryden Lectureship in Research Written 6 January 2016

Keynote Speaker: Dr. Robert H. Liebeck, Boeing Senior Technical Fellow, AIAA Honorary Fellow, and a member of the National Academy of Engineering.

by Lawrence Garrett, AIAA Web Editor

Dr. Robert H. Liebeck (left) receives Dryden Lectureship in Research Medal on the evening of 5 January, at the 2016 AIAA SciTech Forum in San Diego, CA.

Robert H. Liebeck, senior technical fellow at Boeing, delivered the 2016 AIAA Dryden Lectureship in Research on the evening of Jan. 5 at the AIAA Science and Technology Forum and Exposition in San Diego. The lecture was titled “Blended Wing Body Technology Readiness.”

John Vassberg, Boeing technical fellow and chief of aerodynamics for Boeing research and technology, introduced Liebeck as a “world renowned authority in the fields of aerodynamics, hydrodynamics and aircraft design” and the “co-inventor of the blended-wing body concept.”

Liebeck’s lecture took the audience through a comprehensive overview of the development life cycle of the blended-wing aircraft — from the early BWB concepts first created in 1989, through the completion of the test program on April 9, 2013 with the final flight of the X-48C demonstrator.

A big obstacle was getting the flight mechanics robust enough for a blended-wing aircraft to fly like a regular airplane and be lightweight, Liebeck said.

“It was a real challenge to get the inertias close, to have a dynamically scaled airplane,” he said. 

According to Liebeck, a full-scale airplane, with flight-control hardware active, endured 250 hours of tests at the full-scale wind tunnel at NASA’s Langley Research Center.

“To be able to go into a wind tunnel with, in essence, a full-scale airplane was special,” he said.

Liebeck said the BWB project was 50 percent Boeing and 50 percent NASA and that the 2007 X-48B configuration was featured in TIME magazine “as the second best invention of 2007.”

Calling the X-48B flight test program a success, Liebeck said the transition to the X-48C, the low-emission concept evolution, with its two bigger, higher-thrust engines, is the direction the BWB concept is headed. 

Liebeck said that 30 X-48C test flights were completed, and that overall, the whole X-48 project saw a total of 122 test flights. Although the X-48C is on display at the Air Force Flight Test Museum at Edwards Air Force Base and the X-48 equipment is in storage, “those airplanes are still flyable,” he said. 

As a result of the two-decade-plus project, Liebeck said that a robust set of BWB flight-control laws have now been developed and verified.

“We can build the airplane,” he said.

Asked by a member of the audience when a production model might be built, Liebeck said if it were up to him, it would be tomorrow. 

“All I can say is, hey, you can build one of these, and I think you can now … Oh, it’d be higher risk than a tube and wing airplane, but I don’t think there’d be any showstoppers.”


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