BLENDED-WING CRAFT SET FOR TESTS.

Byline: JIM SKEEN Staff Writer

EDWARDS AIR FORCE BASE -- A new experimental plane -- albeit a small one piloted by remote control -- is being prepped for flight at NASA's Dryden Flight Research Center.

Continuing the tradition of X planes that dates back to 1947 at Edwards, Boeing Phantom Works' 21-foot-wide X-48B is testing a design concept called ``blended wing body'' that could provide more lift, greater range and as much as 30 percent greater fuel economy -- valuable for military tankers and transports.

A larger X-48A aircraft was originally planned, but was cancelled as NASA's budgeting priorities shifted. Boeing opted to continue, using a smaller aircraft to help control costs.

``We talked to our management and they felt it was important enough to be a BWB flight control demonstrator,'' said Norm Princen, Boeing Phantom Works' chief engineer for the program. ``Flight control is the highest risk and was the area that needs the most work.''

Unlike the traditional ``tube and wing'' design in which a tubelike fuselage is fitted with wings, the blended-wing body merges the fuselage with the wing -- producing something like a cross between a conventional aircraft and a flying wing such as the B-2 stealth bomber.

Lacking a conventional tail, the X-48B will be controlled using 20 flight control surfaces along the wing's edge.

``If we've done our job right, to the pilot, it ought to fly like any other airplane,'' Princen said.

The X-48B is one-12th the size of what a full-scale blended-wing body transport would be. The 500-pound plane is powered by three turbojet engines that will allow it to fly up to altitudes of 10,000 feet and at speeds of roughly 140 mph.

The aircraft will be controlled by a pilot in a ground station equipped in such a way as to give the feeling of actually being inside the aircraft. The pilot will move a control stick and rudder pedals from an actual aircraft, and video images from the aircraft will be transmitted to the station to provide an out-the-cockpit-window view.

The test program is using two aircraft. The first X-48B was tested in a wind tunnel at NASA's Langley Research Center in Virginia and will serve as a backup to the second aircraft, which was shipped directly to Dryden by Cranfield Aerospace Ltd., a United Kingdom company that built the airplanes for Boeing.

``Earlier wind-tunnel testing and the upcoming flight testing are focused on learning more about the BWB's low-speed flight-control characteristics, especially during takeoffs and landings,'' Princen said. ``Knowing how accurately our models predict these characteristics is an important step in the further development of this concept.''

The test team will be conducting a variety of ground tests this month, including validating engine- and fuel-system integrity, battery endurance, telemetry link communication, flight-control software and low-speed taxiing. In early December, a first flight readiness review will be held with an independent panel before the program advances to high-speed taxi tests and actual flight.

The X-48B team envisions conducting about 25 flights over a six-month period.

Boeing has conducted research on the blended-wing design concept since the early 1990s. In the late 1990s, Stanford University's Flight Research Laboratory and what was then McDonnell Douglas, now part of Boeing, conducted test flights of a 17-foot wingspan, remotely piloted blended-body wing craft at El Mirage dry lake.

Boeing has no plans at this point to use the design for a commercial aircraft. The company is focused on its 787 design, said company spokesman Tom Koehler.

``We're really looking at this from a technology advancement point of view,'' Koehler said.

There is a possibility the design could be used for a multirole military aircraft. Such an aircraft could perform tanker, transport and perhaps even bombing roles.

james.skeen(at)dailynews

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(color -- ran in AV edition only) Boeing's X-48B flying model fuel transport prototype aircraft makes its first public appearance during the open house and air show at Edwards Air Force Base in October.

Gene Blevins/Special to the Daily News