A blended wing body (BWB), also known as blended body or hybrid wing body (HWB), is a fixed-wing aircraft having no clear dividing line between the wings and the main body of the craft. The aircraft has distinct wing and body structures, which are smoothly blended together with no clear dividing line.Crane, Dale. ''Dictionary of Aeronautical Terms, third edition''. Newcastle, Washington: Aviation Supplies & Academics, 1997. . p. 224. This contrasts with a flying wing, which has no distinct

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraf ...

, and a

lifting body A lifting body is a fixed-wing aircraft or spacecraft configuration in which the body itself produces lift. In contrast to a flying wing, which is a wing with minimal or no conventional fuselage, a lifting body can be thought of as a fuselage ...

, which has no distinct

wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is e ...

s. A BWB design may or may not be tailless. The main advantage of the BWB is to reduce

wetted area The surface area that interacts with the working fluid or gas. In maritime industry, maritime use, the wetted area is the area of the hull (watercraft) which is immersed in water. This has a direct relationship on the overall hydrodynamic drag of ...

and the accompanying

form drag Parasitic drag, also known as profile drag, is a type of aerodynamic drag that acts on any object when the object is moving through a fluid. Parasitic drag is a combination of form drag and skin friction drag. It affects all objects regardless of ...

associated with a conventional wing-body junction. It may also be given a wide airfoil-shaped body, allowing the entire craft to generate

lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobil ...

and thus reducing the size and drag of the wings. The BWB configuration is used for both

aircraft An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engine ...

and

underwater glider An underwater glider is a type of autonomous underwater vehicle (AUV) that employs variable-buoyancy propulsion instead of traditional propellers or thrusters. It employs variable buoyancy in a similar way to a profiling float, but unlike a flo ...

History

In the early 1920s Nicolas Woyevodsky developed a theory of the BWB and, following wind tunnel tests, the

Westland Dreadnought The Westland Dreadnought was an experimental single-engined fixed-wing monoplane design for a mail plane created to test the aerodynamic wing and fuselage design ideas of Woyevodsky. It was designed and built by British aircraft manufacturer We ...

was built. It stalled on its first flight in 1924, severely injuring the pilot, and the project was cancelled. The idea was proposed again in the early 1940s for a Miles M.26 airliner project and the Miles M.30 "X Minor" research prototype was built to investigate it. The

McDonnell XP-67 The McDonnell XP-67 "Bat" or "Moonbat"It is unclear if either name was an official USAAF designation; both are used in various sources. It is possible that both are informal nicknames that refer to the aircraft's unique appearance. was a prototy ...

prototype interceptor also flew in 1944 but did not meet expectations.

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...

returned to the concept in the 1990s with an artificially stabilized model (6% scale) called BWB-17, built by Stanford University, which was flown in 1997 and showed good handling qualities. From 2000 NASA went on to develop a remotely controlled research model with a wingspan. NASA has also jointly explored BWB designs for the

Boeing X-48 The Boeing X-48 is an American experimental unmanned aerial vehicle (UAV) built to investigate the characteristics of blended wing body (BWB) aircraft. Boeing designed the X-48 and two examples were built by Cranfield Aerospace in the UK. Bo ...

unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controll ...

. Studies suggested that a BWB airliner carrying from 450 to 800 passengers could achieve fuel savings of over 20 percent.

Airbus Airbus SE (; ; ; ) is a European multinational aerospace corporation. Airbus designs, manufactures and sells civil and military aerospace products worldwide and manufactures aircraft throughout the world. The company has three divisions: ' ...

is studying a BWB design as a possible replacement for the

A320neo family The Airbus A320neo family is a development of the A320 family of narrow-body airliners produced by Airbus. The A320neo family (''neo'' for "new engine option") is based on the previous A319, A320 and A321 ( enhanced variant), which was then ren ...

. A sub-scale model flew for the first time in June 2019 as part of the MAVERIC (Model Aircraft for Validation and Experimentation of Robust Innovative Controls) programme, which Airbus hopes will help it reduce CO₂ emissions by up to 50% relative to 2005 levels. The N3-X NASA concept uses a number of superconducting electric motors to drive the distributed fans to lower the fuel burn, emissions, and noise. The power to drive these electric fans is generated by two wing-tip mounted gas-turbine-driven superconducting electric generators. This idea for a possible future aircraft is called a "hybrid wing body" or sometimes a blended wing body. In this design, the wing blends seamlessly into the body of the aircraft, which makes it extremely aerodynamic and holds great promise for dramatic reductions in fuel consumption, noise and emissions. NASA develops concepts like these to test in computer simulations and as models in wind tunnels to prove whether the possible benefits would actually occur.

Characteristics

The wide interior spaces created by the blending pose novel structural challenges. NASA has been studying foam-clad stitched-fabric

carbon fiber composite Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...

skinning to create uninterrupted cabin space. The BWB form minimises the total

– the surface area of the aircraft skin, thus reducing

skin drag In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding flu ...

to a minimum. It also creates a thickening of the wing root area, allowing a more efficient structure and reduced weight compared to a conventional craft. NASA also plans to integrate Ultra High Bypass (UHB) ratio jet engines with the hybrid wing body. A conventional tubular fuselage carries 12–13% of the total

compared to 31–43% carried by the centerbody in a BWB, where an intermediate lifting-fuselage configuration better suited to narrowbody sized airliners would carry 25–32% for a 6.1–8.2% increase in fuel efficiency. BWB Composite

Potential advantages

*Significant payload advantages in

strategic airlift An airlift is the organized delivery of supplies or personnel primarily via military transport aircraft. Airlifting consists of two distinct types: strategic and tactical. Typically, strategic airlifting involves moving material long distance ...

air freight Air cargo is any property carried or to be carried in an aircraft. Air cargo comprises air freight, air express and airmail. Aircraft types Different cargo can be transported by passenger, cargo or combi aircraft: * Passenger aircraft use the ...

, and aerial refueling roles * Increased fuel efficiency – 10.9% better than a conventional widebody, to over 20% than a comparable conventional aircraft. *Lower noise – NASA audio simulations show a 15 dB reduction of

Boeing 777 The Boeing 777, commonly referred to as the Triple Seven, is an American long-range wide-body airliner developed and manufactured by Boeing Commercial Airplanes. It is the world's largest twinjet. The 777 was designed to bridge the gap betw ...

-class aircraft, while other studies show 22–42 dB reduction below Stage 4 level, depending on configuration.Presentation

Potential disadvantages

*Evacuating a BWB in an emergency could be a challenge. Because of the aircraft's shape, the seating layout would be theatre-style instead of tubular. This imposes inherent limits on the number of exit doors. *It has been suggested that BWB interiors would be windowless, more recent information shows that windows may be positioned differently but involve the same weight penalties as a conventional aircraft. *It has been suggested that passengers at the edges of the cabin may feel uncomfortable during wing roll however, passengers in large conventional aircraft like the 777 are equally susceptible to dutch roll. *The centre wingbox needs to be tall to be used as a passenger cabin, requiring a larger wing span to balance out. *A BWB has more empty weight for a given payload, and may not be economical for short missions of around four or fewer hours. *A larger wing span may be incompatible with some airport infrastructure, requiring folding wings similar to the Boeing777X. *It is more expensive to modify the design to create differently-sized variants compared to a conventional fuselage and wing which can be stretched or shrunk easily.

List of blended wing body aircraft

Northrop Grumman Bat UAV in flight in June 2014

, - , Airbus Maveric, , EU , , UAV , , Experimental , , 2019 , , Prototype , , 1 , , , - ,

Boeing X-45 The Boeing X-45 unmanned combat air vehicle is a concept demonstrator for a next generation of completely autonomous military aircraft, developed by Boeing's Phantom Works. Manufactured by Boeing Integrated Defense Systems, the X-45 was a part ...

, , USA , , UAV , , Experimental , , 2002 , , Prototype , , 2 , , , - ,

(B) , , USA , , UAV , , Experimental , , 2007 , , Prototype , , 2 , , Three engine , - ,

Lockheed A-12 The Lockheed A-12 is a high-altitude, Mach 3+ reconnaissance aircraft built for the United States Central Intelligence Agency (CIA) by Lockheed's Skunk Works, based on the designs of Clarence "Kelly" Johnson. The aircraft was designat ...

, M-21 and

YF-12 The Lockheed YF-12 was an American Mach 3+ capable, high-altitude interceptor prototype, developed and manufactured by American aerospace company Lockheed Corporation. It was developed during the late 1950s and early 1960s as a potent ...

, , US , , Jet , , Reconnaissance , , 1962 , , production , , 18 , , YF-12 was a prototype interceptor , - , Lockheed SR-71 Blackbird , , US , , Jet , , Reconnaissance , , 1964 , , production , , 32 , , , - ,

Northrop Grumman Bat The Northrop Grumman Bat is a medium-altitude unmanned air vehicle originally developed for use by the United States Armed Forces. Designed primarily as an intelligence " ISR" gathering tool, the Bat features payload capacity that is unmatched ...

, , US , , Prop/electric , , Reconnaissance , , 2006 , , production , , 10 , , , - ,

, , USA , , Propeller , , Fighter , , 1944 , , Prototype , , 1 , , Aerofoil profile maintained throughout. , - , Miles M.30 , , UK , , Propeller , , Experimental , , 1942 , , Prototype , , 1 , , , - ,

Rockwell B-1 Lancer The Rockwell B-1 Lancer is a supersonic variable-sweep wing, heavy bomber used by the United States Air Force. It is commonly called the "Bone" (from "B-One"). It is one of three strategic bombers serving in the U.S. Air Force fleet along with ...

, , USA , , Jet , , Bomber , , 1974 , , Production , , 104 , ,

Variable-sweep wing A variable-sweep wing, colloquially known as a "swing wing", is an airplane wing, or set of wings, that may be swept back and then returned to its original straight position during flight. It allows the aircraft's shape to be modified in fli ...

, - , Tupolev Tu-160 , , USSR , , Jet , , Bomber , , 1981 , , Production , , 36 , ,

, - , Tupolev Tu-404 , , Russia , , Propeller , , Airliner , , 1991 , , Project , , 0 , , One of two alternatives studied , - ,

, , UK , , Propeller , , Transport , , 1924 , , Prototype , , 1 , , Mail plane. Aerofoil profile maintained throughout.

In popular culture

''Popular Science'' concept art

A concept photo of a blended wing body commercial aircraft appeared in the November 2003 issue of '' Popular Science'' magazine. Artists

Neill Blomkamp Neill Blomkamp (; born 17 September 1979) is a South African filmmaker. He employs a documentary-style, hand-held, cinéma vérité technique, blending naturalistic and photo-realistic computer-generated effects, and his films often deal wit ...

and Simon van de Lagemaat from

The Embassy Visual Effects The Embassy is a visual effects studio located in Vancouver, British Columbia, Canada. The Embassy is known for its photo-realistic visual effects work on commercials and more recently, features. The studio completed a number of visual effects sho ...

created the photo for the magazine using computer graphics software to depict the future of aviation and air travel. In 2006 the image was used in an email hoax claiming that Boeing had developed a 1000-passenger jetliner (the "Boeing 797") with a "radical Blended Wing design" and Boeing refuted the claim.Christensen, Brett M
"Boeing 797 Hoax"
''Hoax-Slayer,'' April 19, 2012. Retrieved: November 22, 2012.Baseler, Randy

''Boeing blogs: Randy's Journal,'' November 1, 2006. Retrieved: November 22, 2012.