X-48 Project Completes Flight Research for Cleaner, Quieter Aircraft

April 13, 2013

Michael Braukus
Headquarters, Washington
202-358-1979
michael.j.braukus@nasa.gov

Gray Creech
Dryden Flight Research Center
661-276-2662
gray.creech-1@nasa.gov

Tom Koehler
Boeing Research & Technology Communications
425-373-2921
thomas.j.koehler@boeing.com

RELEASE: 13-105

X-48 PROJECT COMPLETES FLIGHT RESEARCH FOR CLEANER, QUIETER AIRCRAFT

EDWARDS, Calif. -- NASA's remotely piloted X-48C hybrid-wing-body
subscale aircraft, which demonstrates technology concepts for cleaner
and quieter commercial air travel, completed an eight-month flight
research campaign on April 9.

The C model of the X-48 aircraft flew its first flight at Edwards Aug.
7 and its 30th flight brought the productive research project to a
close.

"We have accomplished our goals of establishing a ground-to-flight
database, and proving the low speed controllability of the concept
throughout the flight envelope," said Fay Collier, manager of NASA's
Environmentally Responsible Aviation project. "Very quiet and
efficient, the hybrid wing body has shown promise for meeting all of
NASA's environmental goals for future aircraft designs."

The scale-model aircraft, shaped like a manta ray, was designed by The
Boeing Co., built by Cranfield Aerospace Limited of the United
Kingdom, and flown in partnership with NASA. The X-48C is a version
of NASA's X-48B blended wing body aircraft modified to evaluate the
low-speed stability and control of a low-noise version of a notional
hybrid-wing-body design. This design features a flattened fuselage
with no tail, and engines mounted on top of the fuselage at the rear
of the plane. The design stems from concept studies for commercial
aircraft that could be flying within 20 years. The studies are under
way in NASA's Environmentally Responsible Aviation Project.

"Our team has done what we do best: flight-test a unique aircraft and
repeatedly collect data that will be used to design future 'green'
airliners," said Heather Maliska, X-48C project manager at NASA's
Dryden Flight Research Center in California. "It is bittersweet to
see the program come to an end, but we are proud of the safe and
extremely successful joint Boeing and NASA flight test program that
we have conducted."

The X-48C retained most dimensions of the B model, with a wingspan
slightly longer than 20 feet and a weight of about 500 pounds.
Primary changes to the X-48C model from the B model, which flew 92
flights at Dryden between 2007 and 2010, were geared to transforming
it to an airframe noise-shielding configuration. External
modifications included relocating the wingtip winglets inboard next
to the engines, effectively turning them into twin tails. The rear
deck of the aircraft was extended about two feet. Finally, the
project team replaced the X-48B's three 50-pound thrust jet engines
with two 89-pound thrust engines. The aircraft had an estimated top
speed of about 140 mph and a maximum altitude of 10,000 feet.

"Working closely with NASA, we have been privileged throughout X-48
flight-testing to explore and validate what we believe is a
significant breakthrough in the science of flight and this has been a
tremendous success for Boeing," said Bob Liebeck, a Boeing senior
technical fellow and the company's Blended Wing Body (BWB) Program
manager. "We have shown a BWB aircraft, which offers the tremendous
promise of significantly greater fuel efficiency and reduced noise,
can be controlled as effectively as a conventional tube-and-wing
aircraft during takeoffs, landings and other low-speed segments of
the flight regime."

"Our goal was to define the low-speed envelope and explore the
low-speed handling qualities of the blended wing body class of
tailless aircraft, and we have accomplished that," added Mike Kisska,
Boeing X-48 project manager.

Because handling qualities of the X-48C were different from those of
the X-48B, the project team modified the flight control system
software, including flight control limiters to keep the airplane
flying within a safe flight envelope. This enabled a stronger and
safer prototype flight control system suitable for future full-scale
commercial hybrid or blended wing aircraft.

NASA's Aeronautics Research Mission Directorate and Boeing funded the
X-48 technology demonstration research effort, which supported NASA's
goals of reduced fuel burn, emissions, and noise. The Air Force
Research Laboratory in Dayton, Ohio, also was a member of the project
team.

For more information about aeronautics research at NASA, visit:

http://www.aeronautics.nasa.gov


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