Mixed Success for Boeing X-planes at Edwards

AIN Defense Perspective » August 17, 2012
The X-48C blended wing body research vehicle on the ramp at NASA’s Dryden Flight Research Center at Edwards AFB, a few weeks before its first flight. (Photo: Chris Pocock)
August 17, 2012, 10:42 AM

Boeing reported the first flight of the X-48C blended wing body (BWB) research aircraft at Edwards AFB on August 7. The unmanned 8.5-percent scale model reached 5,500 feet during a nine-minute flight. A week later, however, the company’s third X-51 Waverider hypersonic testbed flight ended in failure when its scramjet failed to ignite.

The X-48C is flying under a NASA contract to investigate the aerodynamic characteristics and efficiencies of the BWB concept. Boeing and NASA believe that a full-scale BWB designed for airlift and aerial refueling could offer significantly lower fuel consumption and noise levels than conventional designs. The X-48C is a modified version of the X-48B, another unmanned subscale aircraft, which flew 92 times at the NASA Dryden Flight Research Center between 2007 and 2010. The X-48C is powered by two 89-pound-thrust turbojets instead of the three 50-pound-thrust engines on the -B; and wingtip winglets have been relocated inboard next to the engines on the -C, effectively turning them into twin tails. The aft deck on the -C was extended about two feet at the rear. The UK’s Cranfield Aerospace built the model to Boeing’s design specifications.

The third flight of an X-51A was terminated when a faulty control fin prevented the firing of its Pratt & Whitney Rocketdyne scramjet, according to the U.S. Air Force Research Laboratory (AFRL), which is funding the program. The 25-foot-long unmanned vehicle did launch successfully from the B-52, which flew from Edwards to the test area off the California coast. The test vehicle’s rocket booster also fired as planned. But fifteen seconds after it separated, control of the X-51A was lost.

After a successful test flight of the first X-51A in May 2010 to 70,000 feet and Mach 5, the second X-51A was also lost in June last year after an inlet unstart. Boeing has built four X-51As; the AFRL has not yet decided whether to flight test the last one. The program has already cost $250 million, according to a briefing last June by Joe Vogel, Boeing’s director of hypersonics. But, he continued, “This is a history-making project–the Rosetta Stone of future space access.”


Share this...

Please Register

In order to leave comments you will now need to be a registered user. This change in policy is to protect our site from an increased number of spam comments. Additionally, in the near future you will be able to better manage your AIN subscriptions via this registration system. If you already have an account, click here to log in. Otherwise, click here to register.