Editing Flying wing (section)

===Postwar===
Projects continued to examine the flying wing during the [[postwar]] era. The work on the [[Northrop YB-35|YB-35]] long-range bomber begun in 1941, had continued throughout the war with pre-production machines flying in 1946. This was superseded the next year by conversion of the type to jet power as the [[Northrop YB-49|YB-49]] of 1947.<ref>Northrop Flying Wings: Planes of Fame, Edward Maloney, ISBN 9780915464005</ref>

Initially, the design did not offer a great advantage in range compared to slower piston bomber designs, primarily due to the high fuel consumption of the early turbojets, however, it broke new ground in speed for a large aircraft.

On February 9, 1949, it was flown from Edwards Air Force Base in California, to Andrews Air Force Base, near Washington, D.C., for President Harry Truman's air power demonstration. The flight was made in four hours and 20 minutes, setting a transcontinental speed record.<ref>{{cite web | url=https://www.smithsonianmag.com/air-space-magazine/too-much-too-soon-137775401/#:~:text=On%20February%209%2C%201949%2C%20I,setting%20a%20transcontinental%20speed%20record. | title=The Ride of My Life—on a Flying Wing }}</ref> The YB-49 presented some minor lateral stability problems that were being rectified by a new autopilot system, when the bomber version was cancelled in favour of the much larger but slower B-36. A reconnaissance version continued in development for some time but the aircraft did not enter production.

In the Soviet Union, the [[Chyeranovskii BICh-26|BICh-26]], became one of the first attempts to produce a supersonic jet flying wing aircraft in 1948;<ref>"History of aircraft construction in the USSR" by V.B. Shavrov, Vol. 2. p. 114.</ref> aviation author [[Bill Gunston]] referred to the BICh-26 as being ahead of its time.<ref>Gunston, Bill. "The Osprey Encyclopaedia of Russian Aircraft 1875–1995". London, Osprey. 1995.</ref> 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.<ref>Kılıç,M. 2009. Uçan Kanat, THK basımevi, Ankara, p. 5.</ref><ref>"Turkish Aeronautical Association (THK)", ''Turkish Aircraft Production'' (English-language page).[http://www.tuncay-deniz.com/ENGLISH/THK/thk.html] (retrieved 15 May 2014)</ref> Multiple British manufacturers also explored the concept at this time. Early proposals for the [[Avro Vulcan]], a [[nuclear weapon|nuclear-armed]] [[strategic bomber]] designed by [[Roy Chadwick]], also explored several flying wing arrangements, although the final design had a fuselage.<ref>{{Cite web |url=http://www.verdon-roe.co.uk/#/pictures--videos-avro-aircraft/postwar/698vulcan/avrovulcan/avrovulcansketch |title=Alliott Verdon Roe official web site - Avro Vulcan sketch |access-date=19 February 2015 |archive-date=17 May 2021 |archive-url=https://web.archive.org/web/20210517105101/http://verdon-roe.co.uk/#/pictures--videos-avro-aircraft/postwar/698vulcan/avrovulcan/avrovulcansketch |url-status=dead }}</ref>

There has been continual interest in the flying wing for large transport roles for cargo or passengers. [[Boeing]], [[McDonnell Douglas]], and [[Armstrong Whitworth]] have undertaken design studies on flying wing [[airliner]]s; however, no such airliners have yet been built.<ref name="Tapper" />

Following the arrival of [[supersonic]] 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]] reflection cross-sections. [[Stealth technology]] 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.<ref>[http://www.centennialofflight.gov/essay/Evolution_of_Technology/Stealth_aircraft/Tech31.htm "Stealth Aircraft."] {{webarchive|url=https://web.archive.org/web/20110721035221/http://www.centennialofflight.gov/essay/Evolution_of_Technology/Stealth_aircraft/Tech31.htm |date=21 July 2011}} ''U.S. Centennial of Flight Commission'', 2003. Retrieved: 5 November 2012.</ref> This approach eventually led to the [[Northrop Grumman B-2 Spirit]], a flying wing [[Stealth aircraft|stealth]] bomber.<ref>{{Cite journal |last=Pelletier |first=Alan J |date=September–October 1996 |title=Towards the Ideal Aircraft: The Life and Times of the Flying Wing, Part Two |journal=[[Air Enthusiast]] |volume=65 |pages=8–19}}</ref><ref>{{Cite web |date=2003 |title=Stealth Aircraft |url=http://www.centennialofflight.gov/essay/Evolution_of_Technology/Stealth_aircraft/Tech31.htm |archive-url=https://web.archive.org/web/20110721035221/http://www.centennialofflight.gov/essay/Evolution_of_Technology/Stealth_aircraft/Tech31.htm |archive-date=21 July 2011 |website=U.S. Centennial of Flight Commission}}</ref> 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]] 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.<ref>{{harvnb|Moir|Seabridge|2008|p=397}}</ref><ref name = "sweetman 73">{{harvnb|Sweetman|2005|p=73}}</ref>

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]], [[McDonnell Douglas]], and [[Armstrong Whitworth]], have undertaken design studies on flying wing [[airliner]]s to date; however,<ref name="Tapper" >Tapper (1973)</ref> no such airliners have yet been built as of 2023.{{citation needed|date=December 2011}}

[[File:Wing bi-directional.svg|thumb|Bi-directional flying wing, top-down view]]

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.<ref>Zha, Im & Espinal, [http://www6.miami.edu/acfdlab/projects/AIAA2010-1013_slides_pdf.pdf Toward Zero Sonic-Boom and High Efficiency Supersonic Flight: A Novel Concept of Supersonic Bi-Directional Flying Wing]</ref> NASA has funded a study of the proposal.<ref>{{cite web |last1=Hall |first1=Loura |title=NIAC 2012 Phase I and Phase II Selections |url=https://www.nasa.gov/offices/oct/early_stage_innovation/niac/niac_2012_phaseIandII_awards.html |website=NASA |date=17 July 2017 |access-date=23 September 2020 |archive-date=19 November 2021 |archive-url=https://web.archive.org/web/20211119022839/https://www.nasa.gov/offices/oct/early_stage_innovation/niac/niac_2012_phaseIandII_awards.html |url-status=dead }}</ref> The design is claimed to offer low wave drag, high subsonic efficiency and reduced sonic boom.

Since the end of the [[Cold War]], numerous [[unmanned aerial vehicle]]s (UAVs) featuring the flying wing have been produced. Nations have typically used such platforms for [[aerial reconnaissance]]; such UAVs include the [[Lockheed Martin RQ-170 Sentinel]]<ref>{{cite news |first=David A. |last=Fulghum |title=RQ-170 Has Links to Intelligence Loss to China |url=http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%3a27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3a7544751e-3bdc-4e52-9be7-07000988da92&plckScript=blogScript&plckElementId=blogDest |work=[[Aviation Week & Space Technology]] |date=8 December 2009 |access-date=9 December 2009 |archive-date=4 July 2022 |archive-url=https://web.archive.org/web/20220704211732/https://aviationweek.com/ares?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog:27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post:7544751e-3bdc-4e52-9be7-07000988da92&plckScript=blogScript&plckElementId=blogDest |url-status=dead }}</ref><ref>{{cite news |title=Mystery UAV operation in Afghanistan |url=http://www.shephard.co.uk/news/2393/mystery-uav-operating-in-afghanistan/ |publisher=UV Online |date=10 April 2009 |access-date=9 December 2009 |archive-url=https://web.archive.org/web/20091206023713/http://www.shephard.co.uk/news/2393/mystery-uav-operating-in-afghanistan/ |archive-date=6 December 2009 |url-status=live |df=dmy-all }}</ref> and the [[Northrop Grumman Tern]].<ref>{{Cite web|url=https://www.flightglobal.com/news/articles/northrop-grumman-wins-darpa-tern-programme-420385/|title=Northrop Grumman wins DARPA TERN programme|publisher=Flight Global}}</ref><ref>{{cite web |last1=Smith |first1=Rich |title=General Electric and Northrop Grumman Will Put a Drone on Every Boat |url=https://www.fool.com/investing/2018/03/23/general-electric-and-northrop-grumman-will-put-a-d.aspx |website=The Motley Fool |access-date=23 September 2020 |language=en |date=23 March 2018}}</ref> Civilian companies have also experimented with UAVs, such as the [[Facebook Aquila]], as [[atmospheric satellite]]s.<ref>{{Cite web |url=https://www.popularmechanics.com/flight/drones/g27419696/solar-aircraft-drones/ |title=Solar Drones Are Filling the Skies, But There's Still No Clear Winner |last=Hambling |first=David |date=9 May 2019 |website=Popular Mechanics |language=en-US |access-date=30 May 2019}}</ref><ref name="AT1">{{cite web |url=http://www.aviationtoday.com/2017/11/21/airbus-facebook-partner-haps-connectivity/ |title=Airbus, Facebook Partner on HAPS Connectivity |last=Bellamy III |first=Woodrow |date=21 November 2017 |website=[[Aviation Today]] |location=Rockville, MD |access-date=5 December 2017}}</ref> Various prototype [[unmanned combat aerial vehicle]]s (UCAVs) have been produced, including the [[Dassault nEUROn]],<ref>{{cite magazine| last=Broadbent |first=Mark |title= NEUROn Become's Europe's First Stealth Aircraft to Fly|magazine= [[Air International]] | date= January 2013 |volume= 84 |issue=1 |page=4|issn=0306-5634}}</ref> the [[Sukhoi S-70 Okhotnik-B]],<ref name="Flight testing">{{cite web |url=http://tass.com/defense/1012351 |title=Russia's attack drone prototype to start test flights this year |website=[[TASS]] |date=8 July 2018 |access-date=18 February 2019 |archive-url=https://web.archive.org/web/20190218082020/http://tass.com/defense/1012351 |archive-date=18 February 2019 |url-status=live |df=dmy-all}}</ref>  the [[DRDO Ghatak]], [[DRDO Ghatak|DRDO SWIFT]]  and the [[BAE Systems Taranis]].<ref name="bbc">{{cite web |url=http://news.bbc.co.uk/1/hi/technology/10602105.stm |title=MoD lifts lid on unmanned combat plane prototype |first=Daniel |last=Emery |work=BBC News |date=12 July 2010 |access-date=12 July 2010| archive-url= https://web.archive.org/web/20100712191703/http://news.bbc.co.uk/1/hi/technology/10602105.stm| archive-date= 12 July 2010 | url-status= live}}</ref>