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US4840540A
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Propeller whose blades are provided with slats
Assignee: Deutsches Zentrum für Luft- und Raumfahrt eV
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Filing: 1988-06-22
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Granted: 1989-06-20
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Expires: 2008-06-22
Abstract
Abstract Directly driven propeller whose propeller blades are provided with slats and which is designed for a lower blade tip Mach number in order to reduce the propeller noise. The slats are rigidly connected to the propeller blades and the slat tips lie on a diameter given by the equation ##EQU1## where LTLP=lower transonic limit of the particular blade configuration including slat a o =velocity of sound in air v.sub.∞ =flight speed n=propeller rotational speed.
Inventors
- 👤 Michael Kallergis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:31
CPC Classifications
B; B64; B64C; B64C11/00; B64C11/16; Y; Y10; Y10S; Y10S416/00; Y10S416/02
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
67 words
Propeller, each of whose blades is provided with a slat which is rigidly connected to the propeller blade, and of which the outer radius is smaller than the blade radius, wherein the slat tips lie on a diameter given by the equation ##EQU6## where LTLP=lower transonic limit of the particular blade configuration including slat a o =velocity of sound in air v.sub.∞ =flight speed n=propeller rotational speed.
Claim 2
Dependent Claim
67 words
Propeller, each of whose blades is provided with a slat which is rigidly connected to the propeller blade, and of which the outer radius is smaller than the blade radius, wherein the slat tips lie on a diameter given by the equation ##EQU6## where LTLP=lower transonic limit of the particular blade configuration including slat a o =velocity of sound in air v.sub.∞ =flight speed n=propeller rotational speed.
Claim 3
Dependent Claim
20 words
Propeller as claimed in claim 1, wherein the slat tips are located on a diameter given by the equation ##EQU7##
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-06-19 | 1992-12-19 | 1993-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-06-19 | 1996-12-19 | 1997-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-06-19 | 2000-12-19 | 2001-06-20 | $7700.00 | Window Closed / Lapsed |