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A flying wing is a tailless fixed-wing aircraft that has no definite
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 aircraft t ...
, with its crew, payload, fuel, and equipment housed inside the main wing structure. A flying wing may have various small protuberances such as pods,
nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attache ...
s, blisters, booms, or
vertical stabilizer A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, sta ...
s. Similar aircraft designs, that are not technically flying wings, are sometimes casually referred to as such. These types include blended wing body aircraft and
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 ...
aircraft, which have a fuselage and no definite wings. A pure flying wing is theoretically the lowest drag design configuration for a fixed wing aircraft. However, because it lacks conventional stabilizing surfaces and the associated control surfaces, in its purest form the flying wing suffers from being unstable and difficult to control. The basic flying wing configuration became an object of significant study during the 1920s, often in conjunction with other tailless designs. In the
Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...
, both
Nazi Germany Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...
and the
Allies An alliance is a relationship among people, groups, or states that have joined together for mutual benefit or to achieve some common purpose, whether or not explicit agreement has been worked out among them. Members of an alliance are called ...
made advances in developing flying wings. Military interest in the flying wing waned during the 1950s with the development of supersonic aircraft, but was renewed in the 1980s due to their potential for
stealth technology Stealth technology, also termed low observable technology (LO technology), is a sub-discipline of military tactics and passive and active electronic countermeasures, which covers a range of methods used to make personnel, aircraft, ships, su ...
. This approach eventually led to the
Northrop Grumman B-2 Spirit The Northrop (later Northrop Grumman) B-2 Spirit, also known as the Stealth Bomber, is an American heavy strategic bomber, featuring low-observable stealth technology designed to penetrate dense anti-aircraft defenses. A subsonic flying ...
stealth Stealth may refer to: Military * Stealth technology, technology used to conceal ships, aircraft, and missiles ** Stealth aircraft, aircraft which use stealth technology **Stealth ground vehicle, ground vehicles which use stealth technology ** St ...
bomber. There has been continual interest in using it in the large transport roles for cargo or passengers.
Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and ...
,
McDonnell Douglas McDonnell Douglas was a major American aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own merger with Boeing in 1997, it ...
, and Armstrong Whitworth have undertaken design studies on flying wing airliners; however, no such airliners have yet been built. The flying wing concept is mostly suited to subsonic aircraft. No supersonic flying wing has ever been built.


Design


Overview

A flying wing is an
aeroplane An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spec ...
that has no definite
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 aircraft t ...
or
tailplane A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail ( empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyropl ...
, with its crew, payload, fuel, and equipment housed inside the main wing structure. A flying wing may have various small protuberances such as pods,
nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attache ...
s, blisters, booms, or
vertical stabilizer A vertical stabilizer or tail fin is the static part of the vertical tail of an aircraft. The term is commonly applied to the assembly of both this fixed surface and one or more movable rudders hinged to it. Their role is to provide control, sta ...
s. Crane, Dale: ''Dictionary of Aeronautical Terms'', third edition, p. 224. Aviation Supplies & Academics, 1997. . A clean flying wing is sometimes presented as theoretically the most
aerodynamically Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...
efficient (lowest drag) design configuration for a fixed wing aircraft. It also would offer high structural efficiency for a given wing depth, leading to light weight and high
fuel efficiency Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device ...
. Because it lacks conventional stabilizing surfaces and the associated control surfaces, in its purest form the flying wing suffers from the inherent disadvantages of being unstable and difficult to control. These compromises are difficult to reconcile, and efforts to do so can reduce or even negate the expected advantages of the flying wing design, such as reductions in weight and drag. Moreover, solutions may produce a final design that is still too unsafe for certain uses, such as commercial aviation. Further difficulties arise from the problem of fitting the pilot, engines, flight equipment, and payload all within the depth of the wing section. Other known problems with the flying wing design relate to pitch and yaw. Pitch issues are discussed in the article on tailless aircraft. The problems of yaw are discussed below.


Engineering design

A wing that is made deep enough to contain the pilot, engines, fuel, undercarriage and other necessary equipment will have an increased frontal area, when compared with a conventional wing and long-thin fuselage. This can actually result in higher drag and thus lower efficiency than a conventional design. Typically the solution adopted in this case is to keep the wing reasonably thin, and the aircraft is then fitted with an assortment of blisters, pods, nacelles, fins, and so forth to accommodate all the needs of a practical aircraft. The problem becomes more acute at supersonic speeds, where the drag of a thick wing rises sharply and it is essential for the wing to be made thin. No supersonic flying wing has ever been built.


Directional stability

For any aircraft to fly without constant correction it must have directional stability in yaw. Flying wings lack anywhere to attach an efficient vertical stabilizer or fin. Any fin must attach directly on to the rear part of the wing, giving a small moment arm from the aerodynamic centre, which in turn means that the fin is inefficient and to be effective the fin area must be large. Such a large fin has weight and drag penalties, and can negate the advantages of the flying wing. The problem can be minimized by increasing the wing sweepback and placing twin fins outboard near the tips, as for example in a low-aspect-ratio
delta wing A delta wing is a wing shaped in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta (Δ). Although long studied, it did not find significant applications until the Jet Age, when it proved suita ...
, but given the corresponding reduction in efficiency many flying wings have gentler sweepback and consequently have, at best, marginal stability. The aspect ratio of a swept wing as seen in the direction of the airflow depends on the yaw angle relative to the airflow. Yaw increases the aspect ratio of the leading wing and reduces that of the trailing one. With sufficient sweep-back, differential induced drag resulting from the tip vortices and crossflow is sufficient to naturally re-align the aircraft. A complementary approach uses twist or wash-out, reducing the angle of attack towards the wing tips, together with a swept-back wing planform. The
Dunne D.5 __NOTOC__ The Dunne D.5 was a British experimental aircraft built in 1910. A tailless swept-wing biplane, it was designed by J. W. Dunne and built by Short Brothers at Leysdown for his company, the Blair Atholl Aeroplane Syndicate Ltd. Like it ...
incorporated this principle and its designer
J. W. Dunne John William Dunne (2 December 1875 – 24 August 1949) was a British soldier, aeronautical engineer and philosopher. As a young man he fought in the Second Boer War, before becoming a pioneering aeroplane designer in the early years of the 20th ...
published it in 1913.Dunne, J.W.; "The Theory of the Dunne Aeroplane", ''The Aeronautical Journal'', April 1913, pp.83-102. Reprinted in ''Flight'', 16 Aug to 13 Sept 1913. The wash-out reduces lift at the tips to create a bell-shaped distribution curve across the span, described by Ludwig Prandtl in 1933, and this can be used to optimise weight and drag for a given amount of lift. Another solution is to angle or crank the wing tip sections downward with significant anhedral, increasing the area at the rear of the aircraft when viewed from the side. When combined with sweepback and washout, it can resolve another problem. With a conventional elliptical lift distribution the downgoing elevon causes increased induced drag that causes the aircraft to yaw out of the turn ("adverse yaw"). Washout angles the net aerodynamic vector (lift plus drag) forwards as the angle of attack reduces and, in the extreme, this can create a net forward thrust. The restoration of outer lift by the elevon creates a slight induced thrust for the rear (outer) section of the wing during the turn. This vector essentially pulls the trailing wing forward to cause "proverse yaw", creating a naturally coordinated turn. In his 1913 lecture to the Aeronautical Society of Great Britain, Dunne described the effect as "tangential gain". The existence of proverse yaw was not proved until NASA flew its
Prandtl-D Preliminary Research Aerodynamic Design to Lower Drag, or Prandtl-D was an unmanned experimental glider-aircraft developed by NASA. The acronym is a reference to early German Aerospace Engineer Ludwig Prandtl. The Prandtl-D was a tailless glid ...
tailless demonstrator.


Yaw control

In some flying wing designs, any stabilizing fins and associated control rudders would be too far forward to have much effect, thus alternative means for yaw control are sometimes provided. One solution to the control problem is differential drag: the drag near one wing tip is artificially increased, causing the aircraft to yaw in the direction of that wing. Typical methods include: * Split ailerons. The top surface moves up while the lower surface moves down. Splitting the aileron on one side induces yaw by creating a differential air brake effect. * Spoilers. A spoiler surface in the upper wing skin is raised, to disrupt the airflow and increase drag. This effect is generally accompanied by a loss of lift, which must be compensated for either by the pilot or by design features that automatically compensate. * Spoilerons. An upper surface spoiler that also acts to reduce lift (equivalent to deflecting an aileron upwards), so causing the aircraft to bank in the direction of the turn—the angle of roll causes the wing lift to act in the direction of turn, reducing the amount of drag required to turn the aircraft's longitudinal axis. A consequence of the differential drag method is that if the aircraft maneuvers frequently then it will frequently create drag. So flying wings are at their best when cruising in still air: in turbulent air or when changing course, the aircraft may be less efficient than a conventional design.


Related designs

Some related aircraft that are not strictly flying wings have been described as such. Some types, such as the Northrop Flying Wing (NX-216H), still have a tail stabilizer mounted on tail booms, although they lack a fuselage. Many hang gliders and microlight aircraft are tailless. Although sometimes referred to as flying wings, these types carry the pilot (and engine where fitted) below the wing structure rather than inside it, and so are not true flying wings. An aircraft of sharply swept delta planform and deep centre section represents a borderline case between flying wing, blended wing body, and/or
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 ...
configurations.


History


Early research

Tailless aircraft have been experimented with since the earliest attempts to fly. Britain's
J. W. Dunne John William Dunne (2 December 1875 – 24 August 1949) was a British soldier, aeronautical engineer and philosopher. As a young man he fought in the Second Boer War, before becoming a pioneering aeroplane designer in the early years of the 20th ...
was an early pioneer, his swept-wing biplane and monoplane designs displayed inherent stability as early as 1910. His work directly influenced several other designers, including
G. T. R. Hill Geoffrey Terence Roland Hill, (1895 – 26 December 1955) was a British aviator and aeronautical engineer. Early life Geoffrey Terence Roland Hill was born in 1895, the son of Michael J. M. Hill, Professor of Mathematics at the University Colleg ...
, who developed a series of experimental tailless aircraft designs, collectively known as the Westland-Hill Pterodactyls, during the 1920s and early 1930s. Despite attempts to pursue orders from the Aviation Ministry, the Pterodactyl programme was ultimately cancelled during the mid 1930s before any order for the Mk. VI was issued. Germany's Hugo Junkers patented his own wing-only air transport concept in 1910, seeing it as a natural solution to the problem of building an
airliner An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ai ...
large enough to carry a reasonable passenger load and enough fuel to cross the
Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
in regular service. He believed that the flying wing's potentially large internal volume and low drag made it an obvious design for this role. His deep-chord
monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...
wing was incorporated in the otherwise conventional Junkers J 1 in December 1915. In 1919 he started work on his "Giant" JG1 design, intended to seat passengers within a thick wing, but two years later the Allied Aeronautical Commission of Control ordered the incomplete JG1 destroyed for exceeding postwar size limits on German aircraft. Junkers conceived futuristic flying wings for up to 1,000 passengers; the nearest this came to realization was in the 1931 Junkers G.38 34-seater ''Grossflugzeug'' airliner, which featured a large thick-chord wing providing space for fuel, engines, and two passenger cabins. However, it still required a short fuselage to house the crew and additional passengers. The Soviet Boris Ivanovich Cheranovsky began testing tailless flying wing gliders in 1924. After the 1920s, Soviet designers such as Cheranovsky worked independently and in secret under Stalin. With significant breakthrough in materials and construction methods, aircraft such as the BICh-3, BICh-14, BICh-7A became possible. Men like Chizhevskij and Antonov also came into the spotlight of the Communist Party by designing aircraft like the tailless BOK-5 (Chizhevskij) and OKA-33 (the first ever built by Antonov) which were designated as "motorized gliders" due to their similarity to popular gliders of the time. The BICh-11, developed by Cheranovsky in 1932, competed with the Horten brothers H1 and
Adolf Galland Adolf Josef Ferdinand Galland (19 March 1912 – 9 February 1996) was a German Luftwaffe general and flying ace who served throughout the Second World War in Europe. He flew 705 combat missions, and fought on the Western Front and in the Defenc ...
at the Ninth Glider Competitions in 1933, but was not demonstrated in the 1936 summer Olympics in Berlin. In
Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwee ...
,
Alexander Lippisch Alexander Martin Lippisch (November 2, 1894 – February 11, 1976) was a German aeronautical engineer, a pioneer of aerodynamics who made important contributions to the understanding of tailless aircraft, delta wings and the ground effect, and ...
worked first on tailless types before progressively moving to flying wings, while the Horten brothers developed a series of flying wing gliders through the 1930s. The H1 glider was flown with partial success in 1933, and the subsequent H2 flown successfully in both glider and powered variants. In the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
, from the 1930s
Jack Northrop John Knudsen Northrop (November 10, 1895 – February 18, 1981) was an American aircraft industrialist and designer who founded the Northrop Corporation in 1939. His career began in 1916 as a draftsman for Loughead Aircraft Manufacturing C ...
and
Cheston L. Eshelman Eshelman was a marque of small American automobiles (1953–1961) and other vehicles and implements including motor scooters, garden tractors, pleasure boats, aircraft, golf carts, snowplows, trailers, mail-delivery vehicles and more. The ...
independently worked on their own designs. The Northrop N-1M, a scale prototype for a long-range bomber, first flew in 1940. The
Eshelman FW-5 The Eshelman FW-5 was a 1940s American experimental cabin monoplane designed and built at Dundalk, Maryland by the Cheston L. Eshelman Company. Design and development The FW-5 was a cantilever low-wing monoplane, it had an unusual wing planform i ...
, which was commonly referred to as ''The Wing'', was an experimental cabin monoplane. Other 1930s examples of true flying wings include Frenchman
Charles Fauvel Charles Fauvel (31 December 1904 - 10 September 1979) was a French aircraft designer noted for his tailless and flying wing designs and, in particular, his sailplanes. Fauvel became interested in soaring after witnessing a competition at Vauville ...
's AV3 glider of 1933 and the American Freel Flying Wing glider flown in 1937. featuring a self-stabilizing airfoil on a straight wing.


Second World War

During the
Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...
, aerodynamic issues became sufficiently understood for work on a range of production-representative prototypes to commence. In
Nazi Germany Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...
, the Horten brothers were keen proponents of the flying wing configuration, developing their own designs around it - uniquely for the time using Prandtl's birdlike "bell-shaped lift distribution". One such aircraft they produced was the
Horten H.IV The Horten H.IV was a German tailless flying wing glider in which the pilot was to lie in a prone position to reduce the frontal area, and hence drag. It was designed by Reimar and Walter Horten in Göttingen. Four were built between 1941 an ...
glider, which was produced in low numbers between 1941 and 1943.Dowling, Stephen
"The Flying Wing Decades Ahead of its Time."
''BBC News'', 2 February 2016.
Several other late-war German military designs were based on the flying wing concept, or variations of it, as a proposed solution to extend the range of otherwise very short-range of aircraft powered by early
jet engine A jet engine is a type of reaction engine discharging a fast-moving jet (fluid), jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include Rocket engine, rocket, Pump-jet, water jet, and ...
s. The Horten Ho 229 jet fighter prototype first flew in 1944. It combined a flying wing, or ''Nurflügel'', design with a pair of Junkers Jumo 004 jet engines in its second, or "V2" (V for ''Versuch'') prototype airframe; as such, it was the world's first pure flying wing to be powered by twin
jet engine A jet engine is a type of reaction engine discharging a fast-moving jet (fluid), jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition can include Rocket engine, rocket, Pump-jet, water jet, and ...
s, being first reportedly flown in March 1944. V2 was piloted by Erwin Ziller, who was killed when a flameout in one of its engines led to a crash. Plans were made to produce the type as the Gotha Go 229 during the closing stages of the conflict. Despite intentions to develop the Go 229 and an improved Go P.60 for several roles, including as a night fighter, no Gotha-built Go 229s or P.60s were ever completed. The unflown, nearly completed surviving "V3," or third prototype was captured by American forces and sent back for study; it has ended up in storage at the
Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Found ...
. The Allies also made several relevant advances in the field using a conventional elliptical lift distribution with vertical tail surfaces. During December 1942, Northrop flew the N-9M, a one-third scale development aircraft for a proposed long-range bomber; several were produced, all but one were scrapped following the bomber programme's termination. In Britain, the Baynes Bat glider was flown during wartime; it was a one-third scale experimental aircraft intended to test out the configuration for potential conversion of tanks into temporary gliders. The British
Armstrong Whitworth A.W.52 The Armstrong Whitworth A.W.52 was an early flying wing aircraft designed and produced by British aircraft manufacturer Armstrong Whitworth Aircraft. The A.W.52 emerged out of wartime research into the laminar flow airfoil, which indicated tha ...
G of 1944 was a glider test bed for a proposed large flying wing airliner capable of serving transatlantic routes. The A.W.52G was later followed up by the
Armstrong Whitworth A.W.52 The Armstrong Whitworth A.W.52 was an early flying wing aircraft designed and produced by British aircraft manufacturer Armstrong Whitworth Aircraft. The A.W.52 emerged out of wartime research into the laminar flow airfoil, which indicated tha ...
, an all-metal jet-powered model capable of high speeds for the era; great attention was paid to laminar flow. First flown on 13 November 1947, the A.W.52 yielded disappointing results; the first prototype crashed without loss of life on 30 May 1949, the occasion being the first emergency use of an
ejection seat In aircraft, an ejection seat or ejector seat is a system designed to rescue the pilot or other crew of an aircraft (usually military) in an emergency. In most designs, the seat is propelled out of the aircraft by an explosive charge or rock ...
by a British pilot. The second A.W.52 remained flying with the
Royal Aircraft Establishment The Royal Aircraft Establishment (RAE) was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence (MoD), before finally losing its identity in me ...
until 1954.


Postwar

Projects continued to examine the flying wing during the postwar era. The work on the Northrop N-1M led to the YB-35 long-range bomber, with pre-production machines flying in 1946. This was superseded the next year by conversion of the type to jet power as the YB-49 of 1947. The design did not offer a great advantage in range, presented a number of technical problems and did not enter production. In the Soviet Union, the BICh-26, became one of the first attempts to produce a supersonic jet flying wing aircraft in 1948; aviation author Bill Gunston referred to the BICh-26 as being ahead of its time. However, the aeroplane was not accepted by the Soviet military and the design died with Cheranovsky. Several other nations also opted to undertake flying wing projects. Turkey was one such country, the Turk Hava Kurumu Ucak Fabrikasi producing the THK-13 tailless glider during 1948. Multiple British manufacturers also explored the concept at this time. Early proposals for the Avro Vulcan, a nuclear-armed
strategic bomber A strategic bomber is a medium- to long-range Penetrator (aircraft), penetration bomber aircraft designed to drop large amounts of air-to-ground weaponry onto a distant target for the purposes of debilitating the enemy's capacity to wage war. Unl ...
designed by
Roy Chadwick Roy Chadwick, Order of the British Empire, CBE, FRSA, Fellow of the Royal Aeronautical Society, FRAeS (30 April 1893 – 23 August 1947) was an aircraft design engineer for the Avro Company. Born at Marsh Hall Farm, Farnworth, Widnes, the son o ...
, also explored several flying wing arrangements, although the final design had a fuselage. There has been continual interest in the flying wing for large transport roles for cargo or passengers.
Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and ...
,
McDonnell Douglas McDonnell Douglas was a major American aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own merger with Boeing in 1997, it ...
, and Armstrong Whitworth have undertaken design studies on flying wing airliners; however, no such airliners have yet been built. Following the arrival of
supersonic Supersonic speed is the speed of an object that exceeds the speed of sound ( Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times ...
aircraft during the 1950s, military interest in the flying wing was quickly curtailed, as the concept of adopting a thick wing that accommodated the crew and equipment directly conflicted with the optimal thin wing for supersonic flight. Interest in flying wings was renewed in the 1980s due to their potentially low
radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, Marine radar, ships, spacecraft, guided missiles, motor v ...
reflection cross-sections.
Stealth technology Stealth technology, also termed low observable technology (LO technology), is a sub-discipline of military tactics and passive and active electronic countermeasures, which covers a range of methods used to make personnel, aircraft, ships, su ...
relies on shapes that reflect radar waves only in certain directions, thus making the aircraft hard to detect unless the radar receiver is at a specific position relative to the aircraft—a position that changes continuously as the aircraft moves. This approach eventually led to the
Northrop Grumman B-2 Spirit The Northrop (later Northrop Grumman) B-2 Spirit, also known as the Stealth Bomber, is an American heavy strategic bomber, featuring low-observable stealth technology designed to penetrate dense anti-aircraft defenses. A subsonic flying ...
, a flying wing
stealth Stealth may refer to: Military * Stealth technology, technology used to conceal ships, aircraft, and missiles ** Stealth aircraft, aircraft which use stealth technology **Stealth ground vehicle, ground vehicles which use stealth technology ** St ...
bomber. In this case, the aerodynamic advantages of the flying wing are not the primary reasons for the design's adoption. However, modern computer-controlled
fly-by-wire Fly-by-wire (FBW) is a system that replaces the conventional manual flight controls of an aircraft with an electronic interface. The movements of flight controls are converted to electronic signals transmitted by wires, and flight control ...
systems allow for many of the aerodynamic drawbacks of the flying wing to be minimized, making for an efficient and effectively stable long-range bomber. Due to the practical need for a deep wing, the flying wing concept is mostly adopted for subsonic aircraft. There has been continual interest in using it in the large transport role where the wing is deep enough to hold cargo or passengers. A number of companies, including
Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and ...
,
McDonnell Douglas McDonnell Douglas was a major American aerospace manufacturing corporation and defense contractor, formed by the merger of McDonnell Aircraft and the Douglas Aircraft Company in 1967. Between then and its own merger with Boeing in 1997, it ...
, and Armstrong Whitworth, have undertaken design studies on flying wing
airliner An airliner is a type of aircraft for transporting passengers and air cargo. Such aircraft are most often operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an ai ...
s to date; however,Tapper (1973) no such airliners have yet been built as of 2020. The bi-directional flying wing is a variable-geometry concept comprising a long-span subsonic wing and a short-span supersonic wing, joined in the form of an unequal cross. Proposed in 2011, the low-speed wing would have a thick, rounded airfoil able to contain the payload and a long span for high efficiency, while the high-speed wing would have a thin, sharp-edged airfoil and a shorter span for low drag at supersonic speed. The craft would take off and land with the low-speed wing across the airflow, then rotate a quarter-turn so that the high-speed wing faces the airflow for supersonic travel. NASA has funded a study of the proposal. The design is claimed to offer low wave drag, high subsonic efficiency and reduced sonic boom. Since the end of the
Cold War The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because t ...
, numerous
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 ...
s (UAVs) featuring the flying wing have been produced. Nations have typically used such platforms for
aerial reconnaissance Aerial reconnaissance is reconnaissance for a military or strategic purpose that is conducted using reconnaissance aircraft. The role of reconnaissance can fulfil a variety of requirements including artillery spotting, the collection of im ...
; such UAVs include the Lockheed Martin RQ-170 Sentinel, the Northrop Grumman Tern, and the Nanning Huishi Flying wing. Civilian companies have also experimented with UAVs, such as the Facebook Aquila, as
atmospheric satellite Atmospheric satellite (United States usage, abbreviated atmosat) or pseudo-satellite (British usage) is a marketing term for an aircraft that operates in the atmosphere at high altitudes for extended periods of time, in order to provide servic ...
s. Various prototype
unmanned combat aerial vehicle An unmanned combat aerial vehicle (UCAV), also known as a combat drone, colloquially shortened as drone or battlefield UAV, is an unmanned aerial vehicle (UAV) that is used for intelligence, surveillance, target acquisition, and reconnaissance ...
s (UCAVs) have been produced, including the Dassault nEUROn, the Sukhoi S-70 Okhotnik-B, and the BAE Systems Taranis.


See also

* List of flying wings * Circular wing * Oblique wing * Vincent Burnelli * '' Zanonia macrocarpa''


References


Citations


Bibliography

* . * * . * * * . * . * . *


Further reading

* * . *


External links


History of the Flying Wing
at Century of Flight.



by Joe Mizrahi, ''Wings'', April 1999, Vol. 29, No. 2

*
Flying Wings Are Coming
, ''Popular Mechanics'', 77, No. 3, March 1942. pp. 14-15, 190, 192-193. {{DEFAULTSORT:Flying Wing Wing configurations Aircraft wing design