Blended wing body: Difference between revisions

A '''blended wing body''' ('''BWB'''), also known as '''blended body''', '''hybrid wing body''' ('''HWB''') or a '''lifting aerofoil fuselage''',<ref>{{cite book |title=A Dictionary of Aviation |first=David W. |last=Wragg |isbn=9780850451634978-0-85045-163-4 |edition=first |publisher=Osprey |year=1973 |page=177}}</ref> is a [[fixed-wing aircraft]] having no clear dividing line between the wings and the main body of the craft.<ref name=burl/> The aircraft has distinct wing and body structures, which are smoothly blended together with no clear dividing line.<ref name="Crane">Crane, Dale. ''Dictionary of Aeronautical Terms, third edition''. Newcastle, Washington: Aviation Supplies & Academics, 1997. {{ISBN|1-56027-287-2}}. p. 224.</ref> This contrasts with a [[flying wing]], which has no distinct [[fuselage]], and a [[lifting body]], which has no distinct [[wing]]s. A BWB design may or may not be [[tailless aircraft|tailless]].

In the early 1920s Nicolas Woyevodsky developed a theory of the BWB and, following wind tunnel tests, the [[Westland Dreadnought]] 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]] prototype interceptor also flew in 1944 but did not meet expectations. The 1944 [[CBY-3 Loadmaster|Burnelli CBY-3 Loadmaster]] was a blended wing design intended for Canadian bush operations.<ref name=JAWA1947>{{cite book |title=Jane's all the World's Aircraft 1947 |editor1-last=Bridgman |editor1-first=Leonard |year=1947 |publisher=Sampson Low, Marston & Co |location=London|pages= 96c–97c}}</ref>

[[NASA]] and [[McDonnell Douglas]] returned to the concept in the 1990s with an [[artificial stability|artificially stabilized]] {{convert|17|ft|adj=on}} model (6% scale) called BWB-17, built by [[Stanford University]], which was flown in 1997 and showed good handling qualities.<ref name="Liebeck2004">{{cite journal |author=Liebeck, R.H. |author-link=Robert H. Liebeck |date=January–February 2004 |title=Design of the Blended Wing Body Subsonic Transport |url=http://www.vicomplex.hu/arep/BoeingBWB.pdf |journal=Journal of Aircraft |volume=41 |issue=1 |pages=10–25 |doi=10.2514/1.9084 |url-access= |doi-access=}}</ref>{{rp|16}} From 2000 NASA went on to develop a remotely controlled research model with a {{convert|21|ft|adj=on}} wingspan.

The N3-X NASA concept uses a number of [[Superconducting electric machine|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 wingwingtip-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.{{cn|date=June 2021}}

The wide interior spaces created by the blending pose novel structural challenges. NASA has been studying foam-clad stitched-fabric [[carbon fiber composite]] skinning to create uninterrupted cabin space.<ref>{{cite web|last=Bullis|first=Kevin|date= January 24, 2013|title=NASA has demonstrated a manufacturing breakthrough that will allow hybrid wing aircraft to be scaled up. |url= http://www.technologyreview.com/news/509916/hybrid-wing-uses-half-the-fuel-of-a-standard-airplane/|work=[[MIT Technology Review]]}}</ref>

The BWB form minimisesminimizes the total [[wetted area]] – the surface area of the aircraft skin, thus reducing [[skin drag]] 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 [[High bypass#Extreme bypass jet engines|Ultra High Bypass (UHB) ratio]] jet engines with the hybrid wing body.<ref>{{cite web|last first1 =Michael | last1 = Braukus /| first2 = Kathy | last2 = Barnstorff|date=Jan 7, 2013|title= NASA's Green Aviation Research Throttles Up Into Second Gear|url= http://www.nasa.gov/home/hqnews/2013/jan/HQ_13-002_ERA_Phase_2.html|access-date=Jan 26, 2013|publisher= [[NASA]]}}</ref>

A conventional tubular fuselage carries 12–13% of the total [[Lift (force)|lift]] 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 economy in aircraft|fuel efficiency]].<ref name= "AW160822">{{cite web|author first =Graham | last = Warwick|date=Aug 22, 2016|title= Finding Ultra-Efficient Designs For Smaller Airliners|url= http://aviationweek.com/commercial-aviation/finding-ultra-efficient-designs-smaller-airliners|work=Aviation Week & Space Technology}}</ref>

{{Image frame|width=1028|content=[[File:BWB Composite.jpg|thumb|800px]][[File:NASA M2-F1 in towed flight (ECN-225).jpg|center228px]]
|caption=Spectrum of aircraft design concepts. From left to right: conventional airliner ([[Boeing 757]]), blended wing body ([[Rockwell B-1 Lancer|B-1 Lancer]]), flying wing with bulged fairings ([[Northrop Grumman B-2 Spirit|B-2 Spirit]]), and almost clean [[flying wing]] ([[Northrop YB-49]]). and [[Lifting body]] ([[NASA M2-F1|M2-F1]]).|align=center}}

*Significant payload advantages in [[Airlift |strategic airlift]], [[Cargo airline|air freight]],<ref>{{Cite web|last=2007-05-21T09:38:00+01:00Warwick | first= Graham |title= Boeing works with airlines on commercial blended wing body freighter |url= https://www.flightglobal.com/boeing-works-with-airlines-on-commercial-blended-wing-body-freighter/73711.article|access-date=2023-02-12 |website=Flight Global |language date=en 21 May 2007}}</ref> and [[aerial refueling]] roles

* Increased [[fuel efficiency]] –— 10.9% better than a conventional [[widebody]],<ref name=AW160822/> to over 20% than a comparable conventional aircraft.<ref>{{Cite web|title publisher =NASA –| title = Blended Wing Body Fact Sheet|url= https://www.nasa.gov/centers/langley/news/factsheets/FS-2003-11-81-LaRC.html |access-date=2021-05-17|website=www.nasa.gov|language=en}}</ref>. A 2022 US Air Force report shows a BWB “increases"increases aerodynamic efficiency by at least 30% over current air force tanker and mobility aircraft“aircraft".<ref>{{Cite web|last= Finnerty |first=Ryan|date=2022-10-12|title=US Air Force to test blended-wing logistics aircraft by 2027 |url= https://www.flightglobal.com/fixed-wing/us-air-force-to-test-blended-wing-logistics-aircraft-by-2027/150501.article|access-date=2023-02-12 |website=Flight Global|language=en}}</ref>

*Lower noise –— NASA [[Auralization|audio simulations]] show a 15 [[Decibel |dB]] reduction of [[Boeing 777]]-class aircraft,<ref>{{cite web |last= Warwick |first= Graham |title= Hear This – The BWB is Quiet! |url= http://aviationweek.com/blog/hear-bwb-quiet |work= [[Aviation Week]] |date= Jan 12, 2013}}</ref> while other studies show {{nowrap|22–42&nbsp; dB}} reduction below [[Aircraft noise#Regulation|Stage 4 level]], depending on configuration.<ref name= burl>{{cite web|author first1 =Russell H. | last1 = Thomas, | first2 = Casey L. | last2 = Burley and| first3 = Erik D. | last3 = Olson|title=Hybrid Wing Body Aircraft System Noise Assessment With Propulsion Airframe Aeroacoustic Experiments|url=https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100023399_2010025666.pdf|access-date=26 January 2013|year=2010}} [http://www.aeronautics.nasa.gov/pdf/asm_presentations_status_hwb_community.pdf Presentation] {{webarchive |url = https://web.archive.org/web/20130516232013/http://www.aeronautics.nasa.gov/pdf/asm_presentations_status_hwb_community.pdf |date=2013-05-16 }}</ref>

*Evacuating a BWB in an emergency could be a challenge. Because of the aircraft's shape, the seating layout would be theatretheater-style instead of tubular. This imposes inherent limits on the number of exit doors.<ref>{{cite journalbook |author1 first1 =E. R. | last1 = Galea |author2first2=L. |last2=Filippidis |author3first3=Z. |last3=Wang |author4 first4 = P. J. | last4 = Lawrence |author5first5=J. Ewer |yearlast5=2011Ewer |title chapter = Evacuation Analysis of 1000+ Seat Blended Wing Body Aircraft Configurations: Computer Simulations and Full-scale Evacuation Experiment |year=2011 |title=Pedestrian and Evacuation Dynamics |chapter-url= https://page-one.springer.com/pdf/preview/10.1007/978-1-4419-9725-8_14 |journal=Pedestrian and Evacuation Dynamics |pages=151–161151–61 |doi= 10.1007/978-1-4419-9725-8_14 |isbn= 978-1-4419-9724-1 |s2cid = 55673992}}</ref><ref>{{cite web |url= http://www.evacmod.net/?q=node/2080 |first= Ed |last=Galea |title= Evacuation analysis of 1000+ seat Blended Wing Body aircraft configurations |type=video |website=evacmod.net Evacmod |access-date=August 25, 2015 }}</ref>

*It has been suggested that BWB interiors would be windowless,;<ref name=":0" /> more recent information shows that windows may be positioned differently but involve the same weight penalties as a conventional aircraft.<ref name=":1">{{Cite web|last= Page|first=Mark|date=2018-09-14|title=SINGLESingle-AISLEaisle AIRLINERAirliner DISRUPTIONDisruption WITHwith Aa SINGLEsingle-DECKdeck BLENDEDblended-WINGwing-BODYbody |url=https://www.icas.org/ICAS_ARCHIVE/ICAS2018/data/papers/ICAS2018_0390_paper.pdf|url-status=live|website publisher =icas.org ICAS |archive-url= https://web.archive.org/web/20181220185203/http://icas.org:80/ICAS_ARCHIVE/ICAS2018/data/papers/ICAS2018_0390_paper.pdf |archive-date=2018-12-20 }}</ref>

*It has been suggested that passengers at the edges of the cabin may feel uncomfortable during wing roll;<ref name =":0">{{cite news |url= http://www.imeche.org/news/news-article/boeing-not-convinced-by-blended-wing-aircraft-design-16061502 |title= Boeing not convinced by blended wing aircraft design |date= June 16, 2015 |work= [[Institution of Mechanical Engineers]]}}</ref> however, passengers in large conventional aircraft like the 777 are equally susceptible to dutchsuch roll.<ref name=":1" />

*The centrecenter wingbox needs to be tall to be used as a passenger cabin, requiring a larger wing span to balance out.<ref name= "Leeham3apr2018">{{cite news|date= April 3, 2018|title=Don't look for commercial BWB airplane any time soon, says Boeing's future airplanes head |work=Leeham News|url= https://leehamnews.com/2018/04/03/dont-look-for-commercial-bwb-airplane-any-time-soon-says-boeings-future-airplanes-head/}}</ref>

*A larger wing span may be incompatible with some airport infrastructure, requiring [[Folding wing|folding wings]] similar to the [[Boeing 777X|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.<ref name= "Leeham3apr2018" />

*Pitch control and lift capability at low speed have presented challenges for blended-wing designs. JetZero havehas proposed a novel landing gear design to address these issues for its Z-5 BWB concept. <ref name="AviationWeek21apr2023AW 21Apr2023">{{cite news|date=April 21, 2023|title=JetZero Unveils Midmarket Airliner And Air Force Tanker BWB Plan|work=Aviation Week|url=https://aviationweek.com/aerospace/emerging-technologies/jetzero-unveils-midmarket-airliner-air-force-tanker-bwb-plan}}</ref>

| [[Airbus Maveric]]|| EUMultinational || UAV || Experimental || 2019 || Prototype || 1 || <ref>{{Cite webpress release|url=https://www.airbus.com/newsroom/press-releases/en/2020/02/airbus-reveals-its-blended-wing-aircraft-demonstrator.html|access-date=2023-02-12|website=Airbus|title =Airbus reveals its blended wing aircraft demonstrator| date = 11 February 2020| location = Singapore}}</ref><ref>{{Cite web|date=2020-02-13
| author= Caroline Delbert
|title=Will People Fly In This 'Blended Wing' Airplane? Airbus Built a Prototype To Find Out.|url=https://www.popularmechanics.com/flight/a30916392/maveric-airbus-concept/|access-date=2023-02-12|website=Popular Mechanics|language=en-us}}</ref>

| [[Boeing X-45]] || USAUS || UAV || Experimental || 2002 || Prototype || 2 ||

| [[Boeing X-48]] (C) || USAUS || UAV || Experimental || 2013 || Prototype || 2 || Two engine

| [[Boeing X-48]] (B) || USAUS || UAV || Experimental || 2007 || Prototype || 2 || Three engine

| [[Lockheed A-12]], M-21 and [[Lockheed YF-12|YF-12]] || US || Jet || Reconnaissance || 1962 || productionProduction || 18 || YF-12 was a prototype interceptor

| [[Lockheed SR-71 Blackbird]] || US || Jet || Reconnaissance || 1964 || productionProduction || 32 ||

| [[Northrop Grumman Bat]] || US || Prop/electric || Reconnaissance || 2006 || productionProduction || 10 ||

| [[McDonnell XP-67]] || USAUS || Propeller || Fighter || 1944 || Prototype || 1 || Aerofoil profile maintained throughout.

| [[Rockwell B-1 Lancer]] || USAUS || Jet || Bomber || 1974 || Production || 104 || [[Variable-sweep wing]]

A concept photo of a blended wing body commercial aircraft appeared in the November 2003 issue of ''[[Popular Science]]'' magazine. <ref>{{Cite news |last=Corporation |first=Bonnier |date=November 2003 |title=The Future of Flight |volume=263
| publisher= Bonnier Corporation
|work=Popular Science |issue=5 |url=https://books.google.com/books?id=5bKyC4K5tMwC&dq=Popular+Science&pg=PA81 | pages= 83–86}}</ref> Artists [[Neill Blomkamp]] and Simon van de Lagemaat<!-- mention the artist names since Neill Blomkamp is a noteworthy artist e.g. District 9 --> from [[The Embassy Visual Effects]] created the photo for the magazine using computer graphics software to depict the future of aviation and air travel.<ref>{{Cite web|date=2003-10-16|title=Future Flight: A Gallery of the Next Century in Aviation|url=https://www.popsci.com/military-aviation-space/article/2003-10/future-flight-gallery-next-century-aviation/|access-date=2023-02-12|website=Popular Science|language=en-US}}</ref> 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.<ref>{{cite web |url= http://www.truthorfiction.com/rumors/b/b797.htm |work= [[TruthOrFiction.com]] |title=New Boeing 797 Giant "Blended Wing" Passenger Airliner-Fiction! |date= March 17, 2015}}</ref><ref name="hoaxslay">{{Cite web
|title=Welcome to RunCloud|url = http://www.hoax-slayer.com/boeing-797-hoax.shtml
|access last= Christensen | first= Brett M.
| title=Boeing 797 Hoax
| work =Hoax-Slayer
| date=2023-02-12 April 19, 2012
|website archive-url= https://web.archive.org/web/20120423172557/http://www.hoax-slayer.com/boeing-797-hoax.shtml | archive-date= 2012-04-23 }}</ref><ref name=Baseler>Baseler, Randy. [http://boeingblogs.com/randy/archives/2006/11/air_mail.html "Air mail."] ''Boeing blogs: Randy's Journal,'' November 1, 2006. Retrieved: November 22, 2012.</ref>

* {{cite web |url=http://www.twitt.org/BWBBowers.html |archive-url=https://web.archive.org/web/20021201203443/http://www.twitt.org/BWBBowers.html |titlearchive-date=2002-12-01 |title=Blended-wing-body: Design challenges for the 21st century |date= Sep 16, 2000 |workwebsite= The Wing is The Thing |author= Al Bowers}}

* {{cite webconference |url= https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050182126.pdf |title= Blended-Wing-Body (BWB) Fuselage Structural Design for Weight Reduction |dateconference=46th AprilAIAA/ASME/ASCE/AHS/ASC 2005Structures, |author=Structural V.Dynamics Mukhopadhyay,and Materials Conference |website=NASA LangleyTechnical Reports Server |workdate=April AIAA2005 conference|author=V. Mukhopadhyay}}

* {{cite newsmagazine |url= https://www.newscientist.com/article/dn8310-blended-wing-craft-passes-windtunnel-tests.html |title= 'Blended wing' craft passes wind-tunnel tests |workmagazine= [[New Scientist]] |date= 14 November 2005}}

* {{cite news |url= http://news.bbc.co.uk/2/hi/technology/6120132.stm |title= 'Silent aircraft': How it works |publisherwork= BBC |date= 6 November 2006}}

* {{cite newsconference |url=https://repository.tudelft.nl/islandora/object/uuid:b5e3e6e0-4774-4fbd-b357-1a735dcc183d/datastream/OBJ/download |archive-url=https://web.archive.org/web/20180722122033/https://repository.tudelft.nl/islandora/object/uuid:b5e3e6e0-4774-4fbd-b357-1a735dcc183d/datastream/OBJ/download |titlearchive-date=2018-07-22 |title=A New Structural Design Concept for Blended Wing Body Cabins |authorsbook-title=53rd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference |author=R. Vos, |author2=F.J.J.M.M. Geuskens, |author3=M.F.M. Hoogreef, [[TU Delft]] |date= April 2012 |work= AIAA conference}}

* {{cite webAV media |url= https://www.youtube.com/watch?v=UfD0CIAscOI |archive-url=https://ghostarchive.org/varchive/youtube/20211221/UfD0CIAscOI |archive-date=2021-12-21 |url-status=live |title= A Blended Wing Body Concept |authorpublisher= Cranfield University |author-link= Cranfield UniversityAVD20112012 |via= youtubeYouTube |date= May 4, 2012}}{{cbignore}}

* {{cite web |url= http://www.nasa.gov/topics/aeronautics/features/bwb_main.html |publisherwebsite= NASA |title= X-48 Highlights |date= Apr 18, 2013 |access-date=February 1, 2011 |archive-date=July 8, 2017 |archive-url=https://web.archive.org/web/20170708114009/https://www.nasa.gov/topics/aeronautics/features/bwb_main.html |url-status=dead }}

* {{cite webconference |url= https://elib.dlr.de/95128/1/OPTIMIZATION%20OF%20REVENUE%20SPACE%20OF%20A%20BLENDED%20WING%20BODY%20ICAS.pdf |title= Optimization of revenue space of a blended wing body |authorsbook-title=29th JörgCongress Fuchte,of Tillthe Pfeiffer,International PierCouncil Davideof Ciampa,the BjörnAeronautical Nagel,Sciences Volker(ICAS Gollnick,2014) [[German|author=Jörg AerospaceFuchte Center|DLR]]author2=Till Pfeiffer |workauthor3=Pier CongressDavide ofCiampa the|author4=Björn [[InternationalNagel Council|author5=Volker of the Aeronautical Sciences]]Gollnick |date= SepSeptember 2014}}