The innovative Boeing [NYSE: BA] Blended Wing Body (BWB) research aircraft -- designated
the X-48B -- flew for the first time last week at NASA's Dryden
Flight Research Center at Edwards Air Force Base in California.
The 21-foot wingspan, 500-pound unmanned test vehicle took off for the first
time at 8:42 a.m. Pacific Daylight Time on July 20 and climbed to an altitude
of 7,500 feet before landing 31 minutes later.
"We've successfully passed another milestone in our work
to explore and validate the structural, aerodynamic and operational efficiencies
of the BWB concept," said Bob Liebeck, BWB program manager for Boeing
Phantom Works, the company's advanced R&D unit. "We already
have begun to compare actual flight-test data with the data generated earlier
by our computer models and in the wind tunnel."
The X-48B flight test vehicle was developed by Boeing Phantom Works in cooperation
with NASA and the U.S. Air Force Research Laboratory to gather detailed information
about the stability and flight-control characteristics of the BWB design, especially
during takeoffs and landings. Up to 25 flights are planned to gather data in
these low-speed flight regimes. Following completion of low-speed flight testing,
the X-48B likely will be used to test the BWB's low-noise characteristics,
as well as BWB handling characteristics at transonic speeds.
Two X-48B research vehicles have been built. The vehicle that flew on July
20 is Ship 2, which also was used for ground and taxi testing. Ship 1, a duplicate
of Ship 2, completed extensive wind tunnel testing in 2006 at the Old Dominion
University NASA Langley Full-Scale Tunnel in Virginia. Ship 1 will be available
for use as a backup during the flight test program.
Three turbojet engines enable the composite-skinned research vehicle to fly
up to 10,000 feet and 120 knots in its low-speed configuration. Modifications
would need to be made to the vehicle to enable it to fly at higher speeds.
The unmanned aircraft is remotely piloted from a ground control station in
which the pilot uses conventional aircraft controls and instrumentation while
looking at a monitor fed by a forward-looking camera on the aircraft.
The Boeing BWB design resembles a flying wing, but differs in that the wing
blends smoothly into a wide, flat, tailless fuselage. This fuselage blending
helps to get additional lift with less drag compared to a circular fuselage.
This translates to reduced fuel use at cruise conditions. And because the engines
mount high on the back of the aircraft, there is less noise inside and on the
ground when it is in flight.
"While Boeing constantly explores and applies innovative technologies
to enhance its current and next-generation products, the X-48B is a good example
of how Boeing also looks much farther into the future at revolutionary concepts
that promise even greater breakthroughs in flight," said Bob Krieger,
Boeing chief technology officer and president of Phantom Works.
While a commercial passenger application for the BWB concept is not in Boeing's
current 20-year market outlook, the Advanced Systems organization of Boeing
Integrated Defense Systems' (IDS) is closely monitoring the research
based on the BWB's potential as a flexible, long-range, high-capacity
"The BWB concept holds tremendous promise for the future of military
aviation as a multi-purpose military platform in 15 to 20 years," said
Darryl Davis, Boeing IDS Advanced Systems vice president and general manager
of Advanced Precision Engagement and Mobility Systems. "Its unique design
attributes will result in less fuel burn and a greatly reduced noise footprint,
which are important capabilities to offer our Air Force and mobility customers."
NASA's participation in the project is focused on fundamental, edge-of-the-envelope
flight dynamics and structural concepts of the BWB. Along with hosting
the X-48B flight test and research activities, NASA Dryden provided engineering
and technical support -- expertise garnered from years of operating cutting-edge
unmanned air vehicles.
The two X-48B research vehicles were built by Cranfield Aerospace Ltd., in the
United Kingdom, in accordance with Boeing requirements.