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US4121787A Expired / Lapsed US ⏱️ 0.0 years remaining

Aircraft

Assignee: UK Secretary of State for Defence
•
Filing: 1976-06-29
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Granted: 1978-10-24
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Expires: 1996-06-29
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Abstract

Abstract A supercritical wing section having a large average leading edge radius of curvature, followed on the upper surface by a reduction in curvature and then a knee, or region of positively increased curvature, at between 3% and 13%, preferably 5% to 10%, chord the region of increased curvature being followed by a region of low curvature extending for 30% to 90% of the chord, whereby in use of the wing at low speeds the peak velocity and peak suction are contained, in use thereof at intermediate speeds local supersonic expansion is minimized, and in use thereof in supercritical conditions a region of high expansion, stabilized over the region of increased curvature, is created.

Inventors

  • 👤 Peter Glover Wilby

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 15:18
CPC Classifications
B; B64; B64C; B64C3/00; B64C3/10; B64C3/14; Y; Y02; Y02T; Y02T50/00; Y02T50/10

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 183 words
In a supercritical wing having a large leading edge radius of curvature directly followed chordwise on the upper surface by a curvature transition region and then a directly following low positive curvature region extending for 30% to 90% of the chord, and on the lower surface by a forward region of curvature generally larger than that of the upper surface low curvature region, a transition region characterised by an inflexion and occurring between 50% and 70% chord, and then a rearward region of concave curvature, the improvement comprising a knee in said upper surface curvature transition region, located at between 3% and 13% chord and extending continuously over a substantial portion of the span of the wing, said knee being characterised by a curvature which is positively greater than that immediately forward and that immediately rearward thereof, and said knee being operative to contain the peak velocity and suction at low speeds and thereby to delay the onset of stall, to minimise local supersonic expansion at intermediate speeds, and to create a region of high expansion stabilised over the knee at supercritical speeds.
Claim 2
Dependent Claim 183 words
In a supercritical wing having a large leading edge radius of curvature directly followed chordwise on the upper surface by a curvature transition region and then a directly following low positive curvature region extending for 30% to 90% of the chord, and on the lower surface by a forward region of curvature generally larger than that of the upper surface low curvature region, a transition region characterised by an inflexion and occurring between 50% and 70% chord, and then a rearward region of concave curvature, the improvement comprising a knee in said upper surface curvature transition region, located at between 3% and 13% chord and extending continuously over a substantial portion of the span of the wing, said knee being characterised by a curvature which is positively greater than that immediately forward and that immediately rearward thereof, and said knee being operative to contain the peak velocity and suction at low speeds and thereby to delay the onset of stall, to minimise local supersonic expansion at intermediate speeds, and to create a region of high expansion stabilised over the knee at supercritical speeds.
Claim 3
Dependent Claim 20 words
A supercritical wing as claimed in claim 1 and wherein the knee is located at 0.05 < x/c < 0.1.
Claim 4
Dependent Claim 28 words
A supercritical wing as claimed in claim 1 and wherein the knee is characterised by a change of slope on the order of 3° over 0.3% chord length.

References Cited (Backward Citations)

US1571989A Cited
US1752378A Cited
US2426334A Cited
US3463418A Cited
US3952971A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1981-10-23 1982-04-24 1982-10-24 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1985-10-23 1986-04-24 1986-10-24 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1989-10-23 1990-04-24 1990-10-24 $7700.00 Window Closed / Lapsed

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