EDWARDS, Calif. - NASA's Dryden Flight Research Center and The Boeing Co. are expanding the flight envelope for the X-48B blended wing body research aircraft. 

Flight tests with the 500-pound, remotely piloted test vehicle are now in a second phase involving higher speed regimes. The 21-foot wing span test aircraft is flying without its slats deployed. Slats are flight control surfaces on the leading edges of wings which, when extended, allow an aircraft to take off, fly and land at slower speeds. 

X-48B flight testing is taking place at NASA's Dryden Flight Research Center on Edwards Air Force Base, Calif. NASA Dryden is providing critical support to a Boeing-led project team that also includes the U.S. Air Force Research Laboratory in Dayton, Ohio, and Cranfield Aerospace Ltd., of Bedford, England.

Wired wrote the following in an article in February 2007, "Thinking Outside the Tube"
Ever since Boeing introduced the 707 in the 1950s, passenger jets have looked pretty much the same: long tubes with tails, engines mounted below the wings. That shape may one day be transformed into the graceful silhouette of a manta ray. In February, a 400-pound, 21-foot-wide prototype of just such a bird will start practicing unmanned takeoffs, landings, and tricky slow-speed maneuvers at Edwards Air Force Base. 

Called the X-48B, it's a scaled-down model of a theoretical 500-ton, 240-foot-wide blended-wing aircraft. Aeronautical engineers have long known that this design could be much quieter, more fuel efficient, and far roomier than a conventional cylinder. But recent advances —lightweight composite materials, fly-by-wire controls, sophisticated flight systems — have made building one of these planes more feasible. Commercial versions have been proposed — imagine a flying auditorium—but the X-48B is more likely to debut as a US military transport plane circa 2022." 

 The BWB concept reportedly offers greater structural, aerodynamic and operating efficiencies than today's more conventional tube-and-wing designs. These features translate into greater range, fuel economy, reliability and life cycle savings, as well as lower manufacturing costs. They also allow for a wide variety of potential military and commercial applications.