Blended wing body
Blended wing body (BWB or Hybrid Wing Body, HWB) craft have no clear dividing line between the wings and the main body of the craft. The body form is composed of distinct and separate wing structures, though the wings are smoothly blended into the body, unlike a flying wing which has no distinct fuselage. Many BWB craft have a flattened and airfoil shaped body, which produces most of the lift, the wings contributing the balance.
The purported 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 efficiency and range. A blended wing body can have lift-to-drag ratio 50% greater than a conventional craft.
The Westland Dreadnought was built on the basis of the theories of M. Woyevodsky after wind tunnel tests. It stalled on its first flight in 1924, severely injuring the pilot, and the project was shelved by the British Air Ministry.
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.
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 the 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.
In some ways, the Northrop Grumman B-2 Spirit stealth bomber is a design that 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.
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. Currently, both NASA and Boeing are exploring BWB designs with the X-48 unmanned aerial vehicle. Studies suggest that BWB aircraft, configured for passenger flight, could carry from 450 to 800 passengers and achieve fuel savings of over 20 percent. Other suggestions are better access to emergency exits.
NASA studies with foam-clad stitched-fabric carbonfiber composite paved the way for a 30-foot test structure as the next step for manufacture of hybrid wing bodies, inherently more difficult than traditional tube-and-wing planes. Stitching prevents crack propagation. NASA also plans to integrate Ultra High Bypass (UHB) ratio jet engines with the hybrid wing body.
Potential advantages for aircraft
- Significant payload advantages in strategic airlift/air freight and aerial refueling roles
- Increased fuel efficiency
- Lower noise – NASA audio simulations show a 15dB reduction of Boeing 777-class aircraft, while other studies show 22–42dB reduction below Stage 4 level depending on configuration.
In popular culture
Popular Science concept
A concept photo of a blended wing body commercial aircraft appeared in the October 2003 issue of Popular Science magazine. Artists Neill Blomkamp and Simon van de Lagemaat from The Embassy Visual Effects created the photo for the magazine using computer graphics software to depict the future of aviation and air travel. It is likely the photo was inspired by models of BWB-450, a pre-X-48 concept designed in the late 1990s, or the X-48A concept designed around 2001. The image was subsequently used in hoax emails claiming that Boeing has developed a "1000 passenger Jet Liner" with a "radical Blended Wing design" in direct competition to the Airbus A380. Boeing has denied the claim. 
List of blended wing body aircraft
|AC 20.30||Tailless.|
|AVIC 601-S||China||UAV||Tailless. Series of variants.|
|Boeing X-45C||USA||2002||unmanned aircraft|
|Burnelli CBY-3||Canada||1944||Transport||Prototype||Twin-boom design with lifting fuselage.|
|Lockheed Martin/Boeing RQ-3 DarkStar||USA||1996|
|Lockheed Martin RQ-170 Sentinel||2007||UAV||Tailless|
|McDonnell XP-67||USA||1944||Fighter||Prototype||Twin propellers. Maintained aerofoil profile throughout.|
|Northrop Grumman X-47 Pegasus||USA||2003||unmanned aircraft|
|Silent Aircraft Initiative||2003|
|Westland Dreadnought||UK||1924||mailplane||prototype||sole example destroyed in accident|
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- How design of SAX-40 aircraft reduces noise and improve efficiency
- Progress on the Wingco Atlantica small BWB plane
- Airliners.net photo of the Atlantica prototype aircraft, July 2004
- "Truth Or Fiction" on the rumour of the Boeing 797 blended wing passenger liner
- Blended Wing Body, HAW Hamburg
- Photo-realistic image of blended wing airliner taxiing at airport
- A Blended Wing Body concept by Cranfield University
- NASA Facts - The Blended-Wing-Body
- Blended-wing-body: Design challenges for the 21st century