BWB Arrives at Dryden:
'Flying wing on steroids' could mark
the shape of things to come in aviation'
July 31, 2006
A low-speed, 8.5-percent-scale flight research prototype of Boeing
Phantom Works' Blended Wing Body concept aircraft, also known as the
X-48B, arrived at Dryden in June.
Image above: Ian Brooks, a Cranfield Aerospace employee, works on the Boeing
Phantom Works X-48B Blended Wing Body aircraft. The aircraft and a
second X-48B used in Langley Research Center, Hampton, Va., wind
tunnel tests, arrived at Dryden in June. The low-speed,
8.5-percent-scale flight research prototype is expected to begin a
series of research flights later this year or in early 2007.
NASA Photo by Tony Landis
The X-48B is a subscale testbed for exploring and validating the
structural, aerodynamic and operational advantages of a futuristic
aircraft design called the blended wing body, or BWB. It is similar
to a flying wing, an airplane shaped entirely like an airfoil without
a conventional fuselage or empennage. Flying wing concepts of the
1940s looked like propeller-driven or jet-powered boomerangs. The BWB
design suggests a flying wing on steroids, with several
The front section of a full-scale BWB airplane, containing the
cockpit, extends forward of the wing's leading edge while the central
portion encompasses the passenger or cargo compartment to maximize
payload capacity. The tips of the airfoils end in winglets to reduce
drag and thereby increase fuel efficiency. A big difference between
the BWB and the traditional tube and wing aircraft is that instead of
a conventional tail the BWB relies solely on multiple control
surfaces on the wing for stability and control.
Image above: Boeing Phantom Works employee Rod Wyatt readies the X-48B blended
wing body aircraft for a set of research flights to be flown later
this year or in 2007. Research with the X-48B could result in
development of aircraft capable of carrying larger payloads with
greater fuel efficiency.
NASA Photo by Tony Landis
Boeing officials see the BWB as a flexible, long-range, high-capacity
military aircraft that could be used as a tanker, transport, command
and control platform or weapons carrier.
Designed to fly at altitudes around 7,500 feet, the X-48B's average
research flight is expected to last about an hour and will be focused
on low-speed flight characteristics, said Gary Cosentino, Dryden's
Blended Wing Body project manager and chief engineer. The first in a
series of about five developmental research flights are scheduled to
take place later this year or in early 2007.
The aircraft, featuring a 21-foot wingspan, recently underwent a
paint job at Cranfield Aerospace Ltd. of Cranfield, England, a
subcontractor on the project, and arrived at Dryden with some
assembly required. The wings and landing gear were detached for
transport and additional work is needed to prepare the aircraft for
research flights. The X-48B will fly with a gross takeoff weight of
about 400 pounds. A second BWB aircraft recently underwent a series
of tests in NASA wind tunnels at Langley Research Center, Hampton, Va.
A successful set of five check-out flights with the X-48B, Cosentino
said, could herald the start of a 20- to 25-flight follow-on project
that could last an additional six to nine months and further define
the flight characteristics of the aircraft as the flight envelope is
"It's not so much maturing new technologies as it is working to
understand the characteristics of the shape," he explained.
Dryden is one of several partners in Boeing Phantom Works' Blended
Wing Body concept research efforts, which also include work by
Cranfield, the Air Force Research Laboratory, Langley and the NASA
Subsonic Fixed Wing Program, the latter a key component of the
agency's Aeronautics Research mission directorate.
Blended Wing Body aircraft concepts have been studied since the early
1990s and testing of the shape's aerodynamics has been conducted in
Langley wind tunnels. Flight research is a welcome next step, said
Fay Collier, NASA's Langley-based Fixed Wing Project principle
"We have computational and ground-based testing," Collier said. "This
flight test is going to fill in the flight part of the data for the
low-speed flight regime. It will give us a really good set of data,
from ground to flight, and in this particular case we're looking at
low-speed flight data to go along with computation and wind tunnel
test data we've acquired. It's the final straw in acquiring test data
for that configuration."
Image above: Andy Walster of Cranfield Aerospace takes the stick of the X-48B
blended wing body aircraft simulator.
NASA Photo by Tony Landis
In addition to looking at simulation models, stability and control
limits of the aircraft and control laws for the unique tailless
vehicle, Collier said NASA also is interested in potential benefits
in the areas of noise reduction, lower emissions and aircraft
"This particular configuration is useful in a number of ways. There
are combinations of engines and airframes, like this one, that may
lead to significant noise reduction. This configuration is expected
to be - for a very similar payload - much more fuel efficient than a
conventional configuration," Collier said.
Boeing Phantom Works engineers in Huntington Beach, Calif., specified
the X-48B's outer mold line - the external shape of the airplane -
using their aerodynamic design methods. That information was sent to
Cranfield in a computer-aided design file. Cranfield built the
blended wing body airplane to Phantom Works engineers'
specifications, which are critical to testing a unique aerodynamic
design. Phantom Works is Boeing's advanced research and technology
Boeing officials envision the aircraft as a multi-role platform for
military purposes capable of a wide range of applications, said Norm
H. Princen, Boeing Phantom Works X-48B chief engineer.
"We're really trying, with this vehicle, to prove out the
technologies that would enable a Blended Wing Body to be built," he
Depending on customer need, a next step could be a production
aircraft, Princen said, though a more complicated set of requirements
could lead to a larger demonstrator.
Dave Dyer, Cranfield Aerospace General Manager of UAV Systems and
Cranfield's BWB general manager and chief engineer said the company's
role on the project encompasses more than structures work.
"We've designed and built all the avionics and installed them in the
aircraft and the ground station," Dyer said on a recent visit to
Dryden. "We're supplying a system, not just an airframe. We see it as
we're providing a facility to enable (Boeing) to upload their flight
control laws into the vehicle for experimentation. The job is not
compartmentalized as it might seem; it's an interactive job."
The decision to conduct X-48B flight research at Dryden was an easy
choice, Princen said.
"Dryden is a fantastic place to do flight testing. The facilities
here are really tailored to doing the flight test job and there is
really no other facility like it in the country. The large open space
where we can get airspace set aside for our use, right over the
lakebed, makes a great emergency landing opportunity if you have to
do that. Because we're dealing with an experimental aircraft, you
never know quite what's going to happen.
"The staff here at Dryden have done many other X-plane projects in
the past and we gain from that experience," he continued. "They're
telling us a lot of things that are going to help us avoid problems."
The technical expertise of Dryden's staff has been tapped for
specific tasks, Cosentino said. Dryden team members include Chris
Regan, flight controls; Richard Main, aerodynamics in parameter
identification; and operations engineer Kimberly Vaughn. Also working
on the project are Jessica Lux-Baumann from the Western Aeronautical
Test Range and Tony Kawano, Range Safety Systems Office. Frank
Batteas and Marty Trout are providing support with piloted
Dryden's experience with former X-planes is long.
"The past is applicable," said Cosentino, who was project manager for
the unmanned X-36 and X-45 vehicles. "Every time we fly a subscale
vehicle, we learn something. All the lessons learned from those two
vehicles will be taken into account in general."
The X-36, for example, was similar to the Blended Wing Body in that
it was piloted from a ground station. Better interface with the pilot
is one lesson resulting from that research that will be applied to
work with the X-48B.
Dryden's experience with Altair also contributes to a foundation of
work with UAVs that will help shorten the learning curve on the
X-48B, Cosentino concluded.