Blended Wing Body (BWB) aircraft have a flattened and airfoil shaped body, which produces most of the lift, the wings contributing the balance. The body form is composed of distinct and separate wing structures, though the wings are smoothly blended into the body. By way of contrast, flying wing designs are defined as a tailless fixed-wing aircraft which has no definite fuselage, with most of the crew, payload and equipment being housed inside the main wing structure.[1]
Blended wing body has lift-to-drag ratio 50% greater than conventional airplane. Thus BWB incorporates design features from both a futuristic fuselage and flying wing design. The purported advantages (see Potential advantages below) 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 and range.
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An early aircraft - circa 1926 - exhibiting BWB design principles was the Stout Batwing. The designer William Bushnell Stout, toured the US promoting his aircraft of the future which did not have a traditional fuselage.[2]
The Junkers G.38, 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 box fuselage design. Another example of similar design is Burnelli CBY-3. It had an airfoil shaped fuselage, producing a significant part of the total lift. The CBY-3 however had a fairly conventional twin-boom empennage for added stability.
The Miles M.30 "X Minor" of the early 1940s was an experimental aircraft for research blended wing fuselage designs for an envisaged large airliner. Germany was designing blended wing body jet bombers at the very end of World War II.[3]
In some ways, the B-2 Spirit stealth bomber is a design which falls between classic flying wing and the BWB concept. It is usually classified as a flying wing, 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.[4] 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 21 ft (6.4 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.
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