Blended wing body

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Computer-generated model of the NASA BWB.

NASA's prototype of a Blended Wing aircraft

Blended Wing Body, or BWB, designates an alternative airframe design which incorporates design features from both a traditional tube and wing design into a hybrid flying wing configuration. The advantages of the BWB approach are efficient high-lift wings and a wide airfoil-shaped body. This enables the entire craft to contribute to lift generation with the result of potentially increased fuel economy.

Flying wing designs are defined as having no separate body, only a single wing, though there may be structures protruding from the wing. Blended wing/body aircraft have a flattened and airfoil shaped body, which produces most of the lift to keep itself aloft, and distinct and separate wing structures, though the wings are smoothly blended in with the body.

An early aircraft exhibiting BWB design principles was the Junkers G.38, which flew in 1929. This "super jumbo" airliner of its day, seated thirty-four passengers, six in each of its two meter thick wings, and the balance in the central fuselage. In comparison, a contemporary passenger aircraft, the Ford Trimotor, carried a total of nine passengers in its more traditional wing and tube fuselage design.

In some ways, the B-2 Spirit stealth bomber is a design which falls between classic flying wing concepts and the BWB concept. It is usually classified as a flying wing, however, as the protruding body sections are not much larger than the underlying wing shape structure.

Currently, both NASA and Boeing are exploring BWB designs under the designation X-48. Studies suggest that BWB aircraft, configured for passenger flight, could carry from 450 to 800 passengers and achieve fuel savings of over 20 percent. NASA has been developing, since 2000, a remotely controlled model with a 35 foot (11 m) wingspan. This research is focused on establishing the base data concerning the lift, stall and spin characteristics inherent in a Blended Wing Body design.

Image:BWB-Composite.png

1 Potential advantages
2 Challenges
3 See also
4 External links

[edit] Potential advantages

Improved fuel economy
Reduced noise impact (if the engines are placed above the wings)
Enormous payload advantages in strategic airlift/air freight and aerial refueling roles

[edit] Challenges

Problems that need to be overcome are:

Difficulty in control, owing to the lack of a tail
Greater strength needed to maintain internal pressure, compared to tube-shaped body
Due to the majority of passengers' location far from the roll axis of the aircraft, passengers will be far more affected as a result of a steep turn than they would be in a conventional tube-with-wings airliner, where all the passengers are located immediately next to the roll axis
Most of the aircraft's occupants will not be able to see a window for looking outside the aircraft at their immediate disposal; a system of 'false-windows', such as LCD displays at each seat or each group of seats that would simulate the presence of a window through use of an externally mounted camera. Emergency evacuation of a passenger aircraft may also pose a challenge.