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500:. The Bell proposal reached the wind tunnel testing stage, where the problems of aeroelasticity were confirmed. The structural problems confirmed by the Ju 287 series and the Bell X-1 studies proved so severe that the materials available at the time could not make a wing strong and stiff enough without also making it too heavy to be practical. As a result, forward sweep for high-speed designs was abandoned, until many years later when new structural materials would become available.
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However, if the aeroelastic bending is sufficient, it can counteract this tendency by increasing the angle of attack at the wing tips to such an extent that the tips stall first and one of the main characteristics of the design is lost, on a conventional wing the tips always stall first. Such a tip
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Throughout World War II, numerous fighter, bomber, and other military aircraft can be described as having forward-swept wings, due to the average chord of their wings being forward-sweeping. However, these designs almost always utilized a rearward-swept leading edge, which would technically render
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tends to move spanwise towards the aftmost end of the wing. On a rearward-swept wing this is outwards towards the tip, while on a forward-swept wing it is inwards towards the root. As a result, the dangerous tip stall condition of a rearward-swept design becomes a safer and more controllable root
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was studying the problems of swept wings at the near-sonic speeds of which the new jet engines were capable. He recognised many of the advantages that forward sweep offered over the backwards-swept designs then being developed, and also understood the implications of aeroelastic bending and yaw
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sideways (moves about its vertical axis), one wing retreats while the other advances. On a forward-swept design, this reduces the sweep of the rearward wing, increasing its drag and pushing it further back, increasing the amount of yaw and leading to directional instability. This can lead to a
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consequence of the lift force on forward swept wings twisting the tip upwards under increased lift. On a forward-swept design, this causes a positive feedback loop that increases the angle of incidence at the tip, increasing lift and inducing further deflection, resulting in yet more lift and
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Composite materials allow aeroelastic tailoring, so that as the wing approaches the stall it twists as it bends, so as to reduce the angle of attack at the tips. This ensures that the stall occurs at the wing root, making it more predictable and allowing the ailerons to retain full control.
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was essentially the same airframe re-engined with a pair of
Mikulin-design Soviet jet engines of greater thrust. In 1948, the Soviet Union created the Tsybin LL-3. The prototype would subsequently have a great impact on the Sukhoi SYB-A, which was completed in 1982.
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Forward-swept wings designs, some whose design had begun during the prewar period, were developed during World War II, independently in
Germany, the Soviet Union, Japan, and the United States. An early example to fly, in 1940, was the Soviet
391:, since the wing tips stalls first causing a pitch-up force worsening the stall and making recovery difficult. This effect is less significant with forward sweep because the rearward end carries greater lift and provides stability.
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At large angles of sweep and high speeds, in order to build a structure stiff enough to resist deforming yet light enough to be practicable, advanced materials such as carbon fiber composites are required. Composites also allow
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Such an increase in tip lift under load causes the wing to tighten into turns and may result in a spiral dive from which recovery is not possible. In the worst case, the wing structure can be stressed to the point of failure.
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Belyaev, the author of the below mentioned DB-LK project, tested forward-swept wing gliders BP-2 and BP-3 in 1934 and 1935. Other prewar design studies included the Polish PWS Z-17, Z-18 and Z-47 "Sęp" series.
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In 1954, Wocke returned to the German
Democratic Republic, moving to West Germany shortly afterwards and joining Hamburger Flugzeugbau (HFB) as their chief designer. In Hamburg, Wocke completed work on the
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have slightly forward-swept wings in order to enable the wing root to be located further aft to prevent the wing from obscuring the rear occupant's lateral visibility. Typical examples are the
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prototypes, which were flying fuel tanks, unpowered and designed for towing by larger aircraft. These
Cornelius designs were unusual for being not only forward swept but also tailless.
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Small amounts of sweep do not cause serious problems and even moderate forward sweep allows a significant aft movement of the main spar attachment point and carry-through structure.
469:, on 16 August 1944. Flight tests on this and later variants confirmed the low-speed advantages but also soon revealed the expected problems, preventing high-speed trials.
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for increased visibility, necessitating forward-swept wings to allow the wing root to be positioned behind the pilots’ heads so it does not obscure the view to the side.
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business jet which flew in 1964. The forward sweep enabled the main spar to be moved aft behind the cabin so that the spar did not need to project into the cabin.
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or other devices are not required. At transonic speeds, shockwaves build up first at the root rather than the tip, again helping ensure effective aileron control.
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https://qmro.qmul.ac.uk/xmlui/bitstream/handle/123456789/10947/Hone%20The%20wingtips%20of%20the%20pterosaurs%202015%20Accepted.pdf?sequence=1&isAllowed=y
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Wocke and the incomplete Ju 287 V3 prototype were captured and, in 1946, taken to Moscow where the aircraft was completed and flown the next year as the
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technology and a shift in air combat tactics toward medium range missile engagements decreased the relevance of a highly agile fighter aircraft.
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additional changes in wing shape. The effect of divergence increases with speed. The maximum safe speed below which this does not happen is the
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With the air flowing inwards, wingtip vortices and the accompanying drag are reduced. Instead, the fuselage acts as a very large
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by aligning fibers to influence the nature of deformation to a more favorable shape, impacting stall and other characteristics.
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When the German research reached the United States after the war, a number of proposals were put forward. These included the
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series has a modest forward sweep, with the leading edge almost straight and the trailing edge and quarter-chord line swept.
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is a prototype
Russian single-engine jet trainer aircraft, fitted with forward-swept wings. It first flew in 2015.
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The aft location of the main wing spar would lead to a more efficient interior arrangement with more usable space.
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Spanwise airflow over a forward-swept wing is the reverse of flow over a conventional swept wing.
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The large angles of sweep necessary for high-speed flight remained impractical for many years.
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flew on 18 August 1943. The
Mallard was powered by a single engine, but it was followed by the
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One of the drawbacks of forward swept wings is the increased chance of divergence, an
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allowing a smaller wing. As a result, maneuverability is improved, especially at high
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The forward-swept configuration has a number of characteristics which increase as the
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Moderate forward sweep has been used for similar reasons in many designs, mainly
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stall can be unpredictable, especially where one tip stalls before the other.
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technology demonstrators, first flying in 1984, with forward swept wings and
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and, since wings are generally larger at the root, this raises the maximum
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has a forward sweep. Typically, the leading edge also sweeps forward.
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One problem with the forward-swept design is that when a swept wing
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816:"Механические птицы профессора Беляева / Авиация и время 2008 04"
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control despite loss of lift, and also means that drag-inducing
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research aircraft was cancelled following the German invasion.
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had forward swept wings in order to better balance in flight.
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697:, the X-29 remained controllable at a 67° angle of attack.
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supersonic bomber and forward-swept variants of the
101:. Unsourced material may be challenged and removed.
465:instability. His first such design to fly was the
310:stall on a forward-swept design. This allows full
833:Russian Aviation Page: Sukhoi S-37 Berkut (S-32)
8:
647:displaying forward-swept wing configuration
387:Any swept wing tends to be unstable in the
64:Learn how and when to remove these messages
900:(UK Edition), MCP, 1983, pp. 175–179.
226:Learn how and when to remove this message
161:Learn how and when to remove this message
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677:technology allowed for the design to be
203:of all important aspects of the article.
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199:Please consider expanding the lead to
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45:This article has multiple issues.
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191:may be too short to adequately
86:needs additional citations for
53:or discuss these issues on the
681:and improved maneuverability.
201:provide an accessible overview
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872:. Retrieved 22 August 2005.
619:Scaled Composites Boomerang
490:North American P-51 Mustang
27:Aircraft wing configuration
930:
870:"Dryden Fact Sheet - X-29"
629:PZL Bielsko SZD-50 Puchacz
548:. Many high-wing training
504:Post-WWII general aviation
434:them as high aspect ratio
417:World War II and aftermath
242:Forward-swept wing of the
898:The X-planes, X-1 to X-29
715:fighter prototype at the
570:Other examples include:
456:A model of the Ju 287 V1
693:. Maneuverable at high
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460:Meanwhile in Germany,
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798:"Беляев БП-2(ЦАГИ-2)"
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383:Stall characteristics
377:aeroelastic tailoring
305:Air flowing over any
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679:dynamically unstable
293:Inward spanwise flow
110:"Forward-swept wing"
95:improve this article
914:Wing configurations
757:Variable-sweep wing
671:composite materials
665:In the late 1970s,
18:Forward-swept wings
891:General references
838:2006-02-13 at the
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552:with two seats in
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316:leading edge slots
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285:Main spar location
259:wing configuration
255:reverse-swept wing
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558:Schleicher ASK 13
535:HFB 320 Hansa Jet
496:rocket plane and
443:Cornelius Mallard
436:trapezoidal wings
367:of the aircraft.
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331:angles of attack
327:lift coefficient
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112: –
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106:Find sources:
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84:This article
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896:Miller, J.;
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785:The X-Planes
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783:Miller, J.;
752:Sweep theory
737:
728:KB SAT SR-10
725:
706:
700:Advances in
699:
664:
661:
656:KB SAT SR-10
645:Grumman X-29
625:SZD-9 Bocian
569:
562:Let Kunovice
539:
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483:
478:OKB-1 EF 140
476:. The later
474:OKB-1 EF 131
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244:Sukhoi Su-47
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188:lead section
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93:Please help
88:verification
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47:Please help
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675:Fly-by-wire
601:Saab Safari
596:CZAW Parrot
360:aeroelastic
281:increases.
209:August 2023
763:References
740:pterosaurs
734:In biology
685:built two
609:ARV Super2
590:Cessna 182
586:Cessna 172
582:Cessna NGP
576:Mooney M20
542:sailplanes
524:ARV Super2
462:Hans Wocke
348:Dutch roll
323:wing fence
307:swept wing
121:newspapers
50:improve it
721:air shows
707:In 1997,
611:all have
193:summarize
56:talk page
908:Category
836:Archived
746:See also
636:Fast jet
560:and the
513:LET L-13
494:Bell X-1
428:Babochka
151:May 2021
691:canards
683:Grumman
658:trainer
550:gliders
403:History
312:aileron
135:scholar
868:NASA.
709:Sukhoi
554:tandem
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713:Su-47
667:DARPA
389:stall
142:JSTOR
128:books
726:The
687:X-29
627:and
607:and
588:and
574:The
544:and
343:yaws
267:wing
114:news
253:or
97:by
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