US3845918A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vortex dissipator
Assignee: Rochester Applied Science Associates Inc
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Filing: 1972-12-07
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Granted: 1974-11-05
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Expires: 1992-12-07
Abstract
Abstract A vortex dissipator for the tip of an airfoil or hydrofoil lifting surface is formed as a fixed plate secured to the tip and aligned with the free stream direction. The plate extends forward from the trailing edge of the tip and outward from the suction side of the lifting surface and is configured so that the resultant of the velocity of the free stream flow and the rotational velocity of the vortex produces a stall angle of attack relative to the plate and dissipates much of the strength of the vortex.
Inventors
- 👤 R White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:25
CPC Classifications
B; B64; B64C; B64C23/00; B64C23/06; B64C23/065; B64C23/069; Y; Y02; Y02T; Y02T50/00; Y02T50/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
183 words
A dissipator for the vortex formed by a three-dimensional lifting surface, said dissipator comprising: a. a fixed plate secured to the tip of said lifting surface; b. said plate being aligned with the free stream flow over said lifting surface; c. said plate extending forward from the trailing edge of said tip; d. the length of said plate at said tip in said free stream direction being about 0.3 to 0.6 times the chord of said tip in said free stream direction; e. said plate extending outward from the suction side of said lifting surface far enough to reach the maximum rotatonal velocity region of the vortex formed along said tip in any practical angle of attack of said lifting surface; and f. said plate being arranged relative to the geometry of said lifting surface so that the resultant of the velocity of said free stream flow and the rotational velocity of said vortex produces a stall angle of attack relative to said plate to produce turbulence dOwnstream of said plate sufficient to dissipate a substantial portion of the strength of said vortex.
Claim 2
Dependent Claim
183 words
A dissipator for the vortex formed by a three-dimensional lifting surface, said dissipator comprising: a. a fixed plate secured to the tip of said lifting surface; b. said plate being aligned with the free stream flow over said lifting surface; c. said plate extending forward from the trailing edge of said tip; d. the length of said plate at said tip in said free stream direction being about 0.3 to 0.6 times the chord of said tip in said free stream direction; e. said plate extending outward from the suction side of said lifting surface far enough to reach the maximum rotatonal velocity region of the vortex formed along said tip in any practical angle of attack of said lifting surface; and f. said plate being arranged relative to the geometry of said lifting surface so that the resultant of the velocity of said free stream flow and the rotational velocity of said vortex produces a stall angle of attack relative to said plate to produce turbulence dOwnstream of said plate sufficient to dissipate a substantial portion of the strength of said vortex.
Claim 3
Dependent Claim
45 words
The dissipator of claim 1 wherein the height of said plate at the trailing edge of said plate is at least (C/4) tan Alpha + 0.1C where C equals said chord and Alpha equals the maximum practical aerodynamic angle of attack of said lifting surface.
Claim 4
Dependent Claim
16 words
The dissipator of claim 1 wherein said lifting surface is a flap on an aircraft wing.
Claim 5
Dependent Claim
13 words
The dissipator of claim 1 wherein said lifting surface is a helicopter blade.
Claim 6
Dependent Claim
17 words
The dissipator of claim 1 wherein said lifting surface is a hydrofoil for a water surface craft.
Claim 7
Dependent Claim
15 words
The dissipator of claim 1 wherein said lifting surface is a hydrofoil for a submarine.
Claim 8
Dependent Claim
13 words
The dissipator of claim 1 wherein said lifting surface is an aircraft wing.
Claim 9
Independent Claim
141 words
A method of dissipating the vortex formed at the tip of a three-dimensioned lifting surface, said method comprising: a. leaving the leading edge region of said tip clear to allow said vortex to form along said leading edge region of said tip; b. erecting a fixed plate along the trailing edge region of said tip adjacent said vortex and aligned with the free stream flow over said lifting surface; c. arranging said plate relative to the geometry of said lifting surface so that the resultant of the velocity of said free stream flow and the rotational velocity of said vortex produces a stall angle of attack relative to said plate; and d. letting the turbulence downstream of said plate resulting from said stall angle of attack combine with said vortex to dissipate a substantial portion of the strength of said vortex.
Claim 10
Independent Claim
141 words
A method of dissipating the vortex formed at the tip of a three-dimensioned lifting surface, said method comprising: a. leaving the leading edge region of said tip clear to allow said vortex to form along said leading edge region of said tip; b. erecting a fixed plate along the trailing edge region of said tip adjacent said vortex and aligned with the free stream flow over said lifting surface; c. arranging said plate relative to the geometry of said lifting surface so that the resultant of the velocity of said free stream flow and the rotational velocity of said vortex produces a stall angle of attack relative to said plate; and d. letting the turbulence downstream of said plate resulting from said stall angle of attack combine with said vortex to dissipate a substantial portion of the strength of said vortex.
Claim 11
Dependent Claim
17 words
The method of claim 8 including confining said plate approximately to the rearward half of said tip.
Claim 12
Dependent Claim
27 words
The method of claim 9 including making said plate extend outward from said lifting surface far enough to reach the maximum rotational velocity region of said vortex.
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) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |