US3883095A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reversed cowl flap inlet thrust augmentor
Assignee: National Aeronautics and Space Administration
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Filing: 1973-09-19
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Granted: 1975-05-13
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Expires: 1993-09-19
Abstract
Abstract An adjustable airfoil is described for varying the geometry of a jet inlet and an ejector inlet in a jet engine for providing thrust augmentation and noise reduction. The airfoil comprises essentially a plurality of segments which are extended radially outwardly and retracted relative to the longitudinal axis of the engine as a function of a change in the pressure differential between the upstream and downstream surfaces of the airfoil. A servo mechanism responsive to the change in the pressure differential is coupled to the airfoil to extend and retract the airfoil segments to maintain the pressure at a maximum on the downstream side of the airfoil relative to the pressure on the upstream side of the airfoil. At low speeds, such as at take-offs and landings, the airfoil is fully extended while at high speeds it is fully retracted.
Inventors
- 👤 James C Administrator Fletcher
- 👤 Dah Yu Cheng
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 04:39
CPC Classifications
B; B64; B64D; B64D33/00; B64D33/02; B64C; B64C21/00; B64C21/02; B64D2033/0226; B64D2033/0253; B64D2033/026; B64D2033/0266; B64D2033/0273; B64D2033/0286; Y; Y02; Y02T; Y02T50/00; Y02T50/10; Y10; Y10T; Y10T137/00; Y10T137/0536
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
68 words
In a jet engine assembly, an apparatus for providing thrust augmentation in a forward direction comprising: a controlled movable airfoil having upstream and downstream surfaces relative to said forward direction for entraining external air into the interior of said jet engiNe assembly and developing a thrust component along said direction of motion; and servo means for constantly moving said airfoil to a position that generates maximum thrust augmentation.
Claim 2
Dependent Claim
68 words
In a jet engine assembly, an apparatus for providing thrust augmentation in a forward direction comprising: a controlled movable airfoil having upstream and downstream surfaces relative to said forward direction for entraining external air into the interior of said jet engiNe assembly and developing a thrust component along said direction of motion; and servo means for constantly moving said airfoil to a position that generates maximum thrust augmentation.
Claim 3
Dependent Claim
51 words
An apparatus according to claim 1 wherein said servo means comprises: means for detecting the pressure differential between said upstream and said downstream surfaces; and means responsive to said detecting means for moving said airfoil in response to said pressure differential to a position maximizing the value of said pressure differential.
Claim 4
Dependent Claim
46 words
An apparatus according to claim 2 wherein said movable airfoil comprises a plurality of airfoil segments, each having an upstream and a downstream surface, and which segments are arranged in a circle forming a cylindrical airfoil coaxial with the longitudinal axis of said jet engine assembly.
Claim 5
Dependent Claim
60 words
An apparatus according to claim 3 wherein said upstream and said downstream surfaces of each of said plurality of segments is contoured to permit a selective extension of said segments radially and in an upstream direction from said jet engine assembly and a retraction of said segments to a position flush with an interior surface of said jet engine assembly.
Claim 6
Dependent Claim
42 words
An apparatus according to claim 4 wherein said jet engine assembly comprises a jet engine power section having an entrance lip and an exhaust end, and wherein said plurality of segments is movably mounted at said entrance lip of said power section.
Claim 7
Dependent Claim
62 words
An apparatus according to claim 4 wherein said jet engine assembly comprises a jet engine power section having an entrance lip and an exhaust end and an ejector mounted to the rear end of said engine, said ejector having an entrance lip and an exhaust end and wherein said plurality of segments is movably mounted at said entrance lip of said ejector.
Claim 8
Dependent Claim
56 words
An apparatus according to claim 6 wherein the length and diameter of said ejector is such that said exhaust end of said ejector is upstream of a line along which the resultant velocity of exhaust gases and entrained air in said ejector in a direction normal to the longitudinal axis of said ejector is substantially zero.
Claim 9
Dependent Claim
94 words
In a jet engine assembly, apparatus for providing thrust augmentation in the direction of motion comprising: controlled movable airfoil segments arranged annularly about the longitudinal axis of said jet engine assembly for developing a force vector having components in the radial and forward directions; a differential pressure cell for detecting the difference in pressure between the upstream and downstream surfaces of said airfoil; and a servo mechanism responsive to the output of said differential pressure cell, for moving said airfoil segments to maximize the magnitude of said pressure difference and thus said thrust augmentation.
Claim 10
Dependent Claim
94 words
In a jet engine assembly, apparatus for providing thrust augmentation in the direction of motion comprising: controlled movable airfoil segments arranged annularly about the longitudinal axis of said jet engine assembly for developing a force vector having components in the radial and forward directions; a differential pressure cell for detecting the difference in pressure between the upstream and downstream surfaces of said airfoil; and a servo mechanism responsive to the output of said differential pressure cell, for moving said airfoil segments to maximize the magnitude of said pressure difference and thus said thrust augmentation.
Claim 11
Independent Claim
123 words
A method for reducing the noise output of a jet engine comprising the following steps: attaching a movable airfoil having upstream and downstream surfaces relative to the forward direction of said jet engine at the inlet of said jet engine to entrain air into said inlet; arranging said airfoil such that a component of the force vector generated by said airfoil in cooperation with said air stream is coincident with the forward direction of said jet engine; adjusting the angle of attack of said airfoil to maximize the pressure differential between the upstream and downstream surfaces; and reducing the throttle setting of said jet engine so that the total thrust generated now equals the thrust of said engine without benefit of said airfoil.
Claim 12
Independent Claim
123 words
A method for reducing the noise output of a jet engine comprising the following steps: attaching a movable airfoil having upstream and downstream surfaces relative to the forward direction of said jet engine at the inlet of said jet engine to entrain air into said inlet; arranging said airfoil such that a component of the force vector generated by said airfoil in cooperation with said air stream is coincident with the forward direction of said jet engine; adjusting the angle of attack of said airfoil to maximize the pressure differential between the upstream and downstream surfaces; and reducing the throttle setting of said jet engine so that the total thrust generated now equals the thrust of said engine without benefit 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) | 1978-05-12 | 1978-11-11 | 1979-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-12 | 1982-11-11 | 1983-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-12 | 1986-11-11 | 1987-05-13 | $7700.00 | Window Closed / Lapsed |