Blended wing body

Computer-generated model of the Boeing X-48
NASA's prototype of a Blended Wing aircraft

Blended wing body (BWB or Hybrid Wing Body, HWB[1]) 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.[2] Many BWB craft have a flattened and airfoil shaped body, which produces most of the lift, the wings contributing the balance.

The potential 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 BWB configuration is used for both aircraft and underwater gliders.

History

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.[3]

The first of two Junkers G.38 flew in 1929. The largest aircraft in the world at the time, 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.[4]

A computer stabilized 17-foot model (6% scale) called BWB-17, sponsored by NASA and built by Stanford University, flew in 1997 and showed good handling qualities.[5]

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.[6] Studies suggest that BWB aircraft, configured for passenger flight, could carry from 450 to 800 passengers and achieve fuel savings of over 20 percent.[7] Other suggestions are better access to emergency exits.[8]

Spectrum of aircraft design concepts; (from left to right) conventional airliner, blended wing body, flying wing with bulged fairings and almost clean flying wing. Note that this does not represent either a chronological or technological order. The Boeing 757 (far left) is a commercial aircraft, the Boeing X-48 (2nd image) is the most recently developed, while the Northrop YB-49 (far right) actually predates all other depicted aircraft.

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.[9] NASA also plans to integrate Ultra High Bypass (UHB) ratio jet engines with the hybrid wing body.[10]

Potential advantages for aircraft

Marine applications

The BWB concept is also being used in underwater gliders. The U.S. Navy Office of Naval Research is testing an autonomous glider called the Liberdade Class.

In popular culture

Popular Science concept

The image of the "Boeing 797", used in the hoax email, first appeared in the Popular Science magazine in 2003.

A concept photo of a blended wing body commercial aircraft appeared in the October 2003 issue of Popular Science magazine.[13] 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.[14] 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.[15] The image was subsequently used in emails since 2006 claiming that Boeing has developed a "1000 passenger Jet Liner" (the "Boeing 797") with a "radical Blended Wing design" in direct competition to the Airbus A380. Boeing has denied the claim at the time.[16][17]

List of blended wing body aircraft

Type Country Date Role Status Description
AC 20.30 Tailless.
AVIC 601-S China UAV Tailless. Series of variants.
Boeing X-45C USA 2002 unmanned aircraft
Boeing X-48 USA 2007
Burnelli CBY-3 Canada 1944 Transport Prototype Twin-boom design with lifting fuselage.
Dassault nEUROn UAV Tailless
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

See also

References

Notes

  1. ↑ 1.0 1.1 Russell H. Thomas, Casey L. Burley and Erik D. Olson (2010). "Hybrid Wing Body Aircraft System Noise Assessment With Propulsion Airframe Aeroacoustic Experiments" (PDF). Retrieved 26 January 2013. Presentation
  2. ↑ Crane 1997, p. 224.
  3. ↑ Engineers and Engineering, Volume 39. Philadelphia: Engineers Club of Philadelphia, 1920.
  4. ↑ Herwig and Rode 2000, p. 14.
  5. ↑ Liebeck 2004, p. 16.
  6. ↑ "A flight toward the future." Boeing, August 7, 2012 Retrieved: November 23, 2012.
  7. ↑ Liebeck 2004, p. 21.
  8. ↑ Liebeck 2004, p. 24.
  9. ↑ Bullis, Kevin (January 24, 2013). "NASA has demonstrated a manufacturing breakthrough that will allow hybrid wing aircraft to be scaled up.". Technology Review. Retrieved January 26, 2013.
  10. ↑ Michael Braukus / Kathy Barnstorff (Jan 7, 2013). "NASA's Green Aviation Research Throttles Up Into Second Gear". NASA. Retrieved Jan 26, 2013.
  11. ↑ Warwick, Graham. "Boeing works with airlines on commercial blended wing body freighter." Flight International, May 21, 2007.
  12. ↑ Warwick, Graham (Jan 11, 2013). "Hear This - The BWB is Quiet!". Aviation Week. Retrieved Jan 26, 2013.
  13. ↑ "Future of Flight." Popular Science, October 2003.
  14. ↑ "Future Flight: A Gallery of the Next Century in Aviation." PopSci.com, October 15, 2003. Retrieved: November 22, 2012.
  15. ↑ Chambers, Joseph R. NASA SP-2005-4539 "Innovation In Flight: Research Of The NASA Langley Research Center On Revolutionary Advanced Concepts For Aeronautics". NASA, August 22, 2005.
  16. ↑ Christensen, Brett M. "Boeing 797 Hoax" Hoax-Slayer, April 19, 2012. Retrieved: November 22, 2012.
  17. ↑ Baseler, Randy. "Air mail." Boeing blogs: Randy's Journal, November 1, 2006. Retrieved: November 22, 2012.

Bibliography

  • Crane, Dale. Dictionary of Aeronautical Terms, third edition. Newcastle, Washington: Aviation Supplies & Academics, 1997. ISBN 1-56027-287-2.
  • Herwig, Dieter and Heinz Rode. Luftwaffe Secret Projects: Strategic Bombers 1935–1945. Hinckley, UK: Midland, 2000. ISBN 978-1-85780-092-0.
  • Liebeck, R.H. "Design of the Blended Wing Body Subsonic Transport." AIAA Journal of Aircraft, Volume 41, Issue 1, January–February 2004, pp. 10–25.
  • Rose, Bill. Secret Projects: Flying Wings and Tailless Aircraft. Hinckley, UK: Midland Publishing, 2010. ISBN 978-1-85780-320-4.

External links