Patent US3881669A successfully refreshed from Google Patents.
US3881669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for elimination of airfoil trailing vortices
Assignee: Individual
•
Filing: 1973-05-16
•
Granted: 1975-05-06
•
Expires: 1993-05-16
Abstract
Abstract Herein are disclosed a method and apparatus for eliminating or substantially attenuating the dangerous vortices which typically trail the airfoils of heavier-than-air aircraft in flight. The disclosed method consists of injecting a fluid stream into the core of the vortex (a) in a direction such that the longitudinal axis of the injected fluid stream is substantially colinear and coaxial with the longitudinal axis of the vortex where the injected stream enters the vortex core, and (b) at a momentum flux of such magnitude relative to that of the free air stream that the vortex will be rendered hydrodynamically unstable. The criteria as to the direction and the magnitude of the momentum flux of the injected fluid stream are disclosed as critical to the successful practice of the invention. It is preferable that the departure from colinearity be not more than 4*. The apparatus of the invention comprises, in combination with an airfoil, a pair of nozzles adapted for injecting a fluid stream of the required orientation and of a momentum flux of such magnitude relative to the free air stream into the trailing vortex that the trailing vortex will be rendered hydrodynamically unstable and apparatus for supplying a suitable fluid to the nozzles.
Inventors
- 👤 Martin Lessen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:19
CPC Classifications
B; B64; B64C; B64C23/00; B64C23/06; Y; Y02; Y02T; Y02T50/00; Y02T50/10
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
117 words
Method for rapidly dissipating the vortex trailing an airfoil in flight, said method consisting of injecting a substantially linear fluid stream substantially coaxially into said vortex (a) in a direction such that there is no more than about four degrees of misalignment between the longitudinal axis of the injected fluid stream and the longitudinal axis of said vortex substantially at the point of entry of the stream into the core of the trailing vortex, and (b) at a substantially linear momentum flux of such magnitude relative to that of the free air stream that said trailing vortex will be rendered hydrodynamically unstable, whereby disturbances and hence turbulence in said vortex will grow rapidly to dissipate said vortex.
Claim 2
Dependent Claim
117 words
Method for rapidly dissipating the vortex trailing an airfoil in flight, said method consisting of injecting a substantially linear fluid stream substantially coaxially into said vortex (a) in a direction such that there is no more than about four degrees of misalignment between the longitudinal axis of the injected fluid stream and the longitudinal axis of said vortex substantially at the point of entry of the stream into the core of the trailing vortex, and (b) at a substantially linear momentum flux of such magnitude relative to that of the free air stream that said trailing vortex will be rendered hydrodynamically unstable, whereby disturbances and hence turbulence in said vortex will grow rapidly to dissipate said vortex.
Claim 3
Dependent Claim
11 words
Method according to claim 1 wherein said fluid is a gas.
Claim 4
Dependent Claim
11 words
Method according to claim 2 wherein said gaseous fluid is air.
Claim 5
Dependent Claim
129 words
An airfoil, said airfoil having an upper surface over which a vortex is formed and from which said vortex trails, said airfoil having a trailing edge, said trailing vortex having a core and defining a curvilinear longitudinal axis, and means mounted on said airfoil and spaced from said trailing edge for injecting a fluid substantially linearly into said trailing vortex in a direction substantially coaxial and colinear with no more than about 4* of misalignment from said axis at the point of entry into the vortex core and at a substantially linear momentum flux of a magnitude relative to the free air stream proximate the airfoil which renders the modified trailing vortex hydrodynamically unstable, whereby disturbances and hence turbulence in said vortex will grow rapidly to dissipate said vortex.
Claim 6
Dependent Claim
129 words
An airfoil, said airfoil having an upper surface over which a vortex is formed and from which said vortex trails, said airfoil having a trailing edge, said trailing vortex having a core and defining a curvilinear longitudinal axis, and means mounted on said airfoil and spaced from said trailing edge for injecting a fluid substantially linearly into said trailing vortex in a direction substantially coaxial and colinear with no more than about 4* of misalignment from said axis at the point of entry into the vortex core and at a substantially linear momentum flux of a magnitude relative to the free air stream proximate the airfoil which renders the modified trailing vortex hydrodynamically unstable, whereby disturbances and hence turbulence in said vortex will grow rapidly to dissipate said vortex.
Claim 7
Dependent Claim
100 words
An airfoil as set forth in claim 4, said means comprising an elongated duct mounted within said airfoil and having a first and a second end, a source of compressed air, means interconnecting said first end of said duct with said cource of compressed air, a nozzle having a longitudinal axis, means on said airfoil mounting said nozzle with its axis extending in a direction substantially colinear and coaxial with the axis of said vortex at the point of entry of the discharge from said Nozzle into the core of the vortex, and means interconnecting said nozzle and said duct.
Claim 8
Dependent Claim
18 words
Apparatus as set forth in claim 5, including swirl generating means mounted between said nozzle and said duct.
Claim 9
Dependent Claim
55 words
Apparatus as set forth in claim 4, wherein said means comprises a jet engine, means mounting said jet engine on the said airfoil, said jet engine having a discharge end directed colinear and coaxial with the axis of said trailing vortex at the point of entry of said discharge into the core of the vortex.
Claim 10
Dependent Claim
14 words
An airfoil in accordance with claim 4 comprising a wing of a fixed-wing aircraft.
Claim 11
Dependent Claim
14 words
An airfoil in accordance with claim 4 comprising a wing of a variable-wing aircraft.
Claim 12
Dependent Claim
16 words
An airfoil in accordance with claim 4 comprising a rotor blade of a rotating blade aircraft.
Claim 13
Dependent Claim
26 words
Apparatus as set forth in claim 5, including means rotatably mounting said nozzle to vary its angle with respect to the longitudinal axis of the airfoil.
Claim 14
Dependent Claim
17 words
Apparatus as set forth in claim 4, wherein said airfoil comprises a flap of a fixed-wing aircraft.
Claim 15
Dependent Claim
22 words
Apparatus as set forth in claim 12, wherein said means are rotatably mounted with respect to the longitudinal axis of said airfoil.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-05 | 1978-11-04 | 1979-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-05 | 1982-11-04 | 1983-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-05 | 1986-11-04 | 1987-05-06 | $7700.00 | Window Closed / Lapsed |