BLENDED WING BODY AIRCRAFT



Image courtesy NASA.

Blended Wing Body Aircraft
Tech Level: 12

Blended Wing Body (BWB) Aircraft are also more simply called Blended Wing Aircraft, or Hybrid Wing/Body Aircraft. NASA is currently studying the design under its Fundamental Aeronautics research program in cooperation with Boeing. Both hope to have a working blended wing jetliner commercially available by 2020.

Blended Wing aircraft are a type of hybrid flying wing aircraft that merges the fuselage and wing into one composite lifting body. In conventional tube-and-wing layouts in modern jetliners, only the wings provide lift. In a flying wing configuration, the entire body of the aircraft provides lift instead. Pure flying wings maximize lift and reduce drag significantly, but can have problems with stability. The B-2 bomber, perhaps the most famous flying wing aircraft, compensates by using highly sophisticated computer controls to keep the airframe stable in flight.

However, such a solution is not always practical or economical, especially for commercial jets. A BWB aircraft makes a good compromise, optimizing the blend of flying wing and conventional aircraft. The result is a sleek angular wedge shape that some have compared to a airborne manta ray.

The greater lift and lessened drag of the design could result in up to a 20% greater fuel efficiency over current jetliners and could have ranges of up to 7000 miles. The configuration has two general options for engine placement. Either external rear-mounted pods, or internally mounted engines with no external structure. The latter internal engines would have the advantage of reducing drag even further and reducing external engine noise, but may prove more difficult and expensive to repair and maintain.

The joint Boeing-NASA scaled-down prototype is dubbed the X-48B, which is built from composite materials and has wingspan of 21 feet. It has been undergoing test flights since 2007 in order to build up a base of performance data for BWB aircraft. Two more sophisticated prototypes are scheduled to begin test flights in 2011.

If ever put into service, a BWB jetliner could carry up to 800 passengers, though a smaller, 450-passenger version is likely to be built first. It would cruise at about Mach .85. The larger version would have a wingspan of about 300 feet, and be composed of tough lightweight composites, making it lighter than conventional aircraft of comparable size.

Its interior would be laid out differently from modern passenger jets; passenger seating would be spread out horizontally across the mid section of the craft, as much as 50 seats across at the vehicle’s widest point, and may be double-decker to take full advantage of its internal volume. Boarding of both passengers and cargo would be performed from the vehicle’s aft section.


The interior cabiin configuration of a proposed BWB airliner. Image courtesy NASA.

FURTHER INFORMATION

http://www.twitt.org/bldwing.htm

http://www.aviationweek.com/aw/generic/story.jsp?id=news/Body011309.xml&headline=NASA%20Pushes%20Blended%20Wing/Body%20&channel=space

http://oea.larc.nasa.gov/PAIS/BWB.html

http://en.wikipedia.org/wiki/Blended_wing_body

http://en.wikipedia.org/wiki/Boeing_X-48


Article added 1/27/10

HOME CONVENTIONAL AIRCRAFT HUB