US4750693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for reducing the frictional drag of moving bodies
Assignee: Airbus Defence and Space GmbH
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Filing: 1986-08-05
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Granted: 1988-06-14
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Expires: 2006-08-05
Abstract
Abstract A device for reducing the frictional drag inherent in flow mechanics in airborne, waterborne and space vehicles in which the surface of a body in a flowing medium is provided with an asymmetrical microstructure in the form of grooved profiles whose dimensions do not essentially exceed the average free travel length of the molecules of the medium.
Inventors
- 👤 Gerhard Lobert
- 👤 Oskar Bschorr
- 👤 Hans Spies
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 16:26
CPC Classifications
B; B64; B64C; B64C21/00; B64C21/10; F; F15; F15D; F15D1/00; F15D1/002; F15D1/0025; F15D1/003; F15D1/0035; F15D1/0045; Y; Y02; Y02T; Y02T50/00; Y02T50/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
98 words
In a device for reduction of the frictional drag inherent in flow mechanics in bodies moving through a fluid medium in a given direction, such as airborne, waterborne and space vehicles, the improvement comprising that the surface of the moving body is provided with an asymmetrical microstructure in the form of grooved profiles extending transversely to said given direction whose depths do not substantially exceed the average free travel length of the molecules of the medium or the average free travel length of the fluid particles of the turbulent boundary layer, and lie in the region of micrometers.
Claim 2
Dependent Claim
98 words
In a device for reduction of the frictional drag inherent in flow mechanics in bodies moving through a fluid medium in a given direction, such as airborne, waterborne and space vehicles, the improvement comprising that the surface of the moving body is provided with an asymmetrical microstructure in the form of grooved profiles extending transversely to said given direction whose depths do not substantially exceed the average free travel length of the molecules of the medium or the average free travel length of the fluid particles of the turbulent boundary layer, and lie in the region of micrometers.
Claim 3
Dependent Claim
23 words
A device according to claim 1, wherein said asymmetrical microstructure is constructed microscopically for influencing the average direction of emission of the molecules.
Claim 4
Dependent Claim
21 words
A device according to claim 1, wherein the grooved profile of the asymmetrical microscopic microstructure is additionally provided with asymmetrical subgrooves.
Claim 5
Dependent Claim
19 words
A device according to claim 1, wherein the grooved profile of the asymmetrical microscopic microstructure exhibits a three-dimensional design.
Claim 6
Dependent Claim
21 words
A device according to claim 2, wherein the grooved profile of the asymmetrical microscopic microstructure is additionally provided with asymmetrical subgrooves.
References Cited (Backward Citations)
FR393086A
Cited
GB104114A
Cited
FR587211A
Cited
GB324441A
Cited
US1903823A
Cited
US4044797A
Cited
US4180290A
Cited
US4706910A
Cited
US4650138A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-06-14 | 1991-12-14 | 1992-06-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-14 | 1995-12-14 | 1996-06-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-14 | 1999-12-14 | 2000-06-14 | $7700.00 | Window Closed / Lapsed |