US3610262A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stowable vane sonic throat inlet for jet aircraft noise suppression
Assignee: Boeing Co
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Filing: 1969-10-07
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Granted: 1971-10-05
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Expires: 1989-10-07
Abstract
Abstract An apparatus to suppress fan or compressor noise emitted in a forward direction from the inlet of an airplane jet engine, particularly for approach mode operation of the airplane. There are in the engine inlet at a location forward of the compressor a set of vanes which are swing mounted in the inlet cowl wall. For low engine thrust values, the vanes are swung to a position where they extend radially inwardly in a plane generally transverse to the centerline axis of the inlet to provide a flow restriction in the inlet. This causes the air in the inlet to flow at, or nearly at, sonic velocity in the region of the vanes. For moderately high thrust settings and engine speeds where greater airflow through the inlet is required, the vanes are swung rearwardly to an angle which provides greater effective flow area through the inlet and maintains Mach 1.0 flow velocity in the vane region to achieve high noise attenuation. During airplane cruise operation, the vanes are swung into the inlet wall to provide a substantially settings engine inlet.
Inventors
- 👤 William H Wise
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:57
CPC Classifications
F; F02; F02C; F02C7/00; F02C7/04; F02C7/045; Y; Y10; Y10T; Y10T137/00; Y10T137/0536
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
177 words
In an air inlet for an air breathing engine wherein said inlet has an inlet wall defining an inlet opening which has a longitudinal axis along which air flows through said opening, an apparatus for controlling air flow through said opening comprising: a plurality of tapered vanes each rotatably mounted about an axis of rotation for movement from stowed positions along said wall to minimum flow area positions wherein said tapered vanes are substantially angularly displaced from said wall, each of said tapered vanes comprising symmetrically disposed oppositely facing exterior surfaces defining the cross sections of an airfoil member which has a uniform taper in thickness from a minimum at the end of the vane farthest from said axis of rotation to a maximum near the end closest to said axis of rotation, said uniform taper in thickness being such that when said vanes are disposed in said minimum flow area positions, each of the vane edges established by the points of maximum thickness of said cross sections lie substantially along planes passing through said longitudinal axis.
Claim 2
Dependent Claim
177 words
In an air inlet for an air breathing engine wherein said inlet has an inlet wall defining an inlet opening which has a longitudinal axis along which air flows through said opening, an apparatus for controlling air flow through said opening comprising: a plurality of tapered vanes each rotatably mounted about an axis of rotation for movement from stowed positions along said wall to minimum flow area positions wherein said tapered vanes are substantially angularly displaced from said wall, each of said tapered vanes comprising symmetrically disposed oppositely facing exterior surfaces defining the cross sections of an airfoil member which has a uniform taper in thickness from a minimum at the end of the vane farthest from said axis of rotation to a maximum near the end closest to said axis of rotation, said uniform taper in thickness being such that when said vanes are disposed in said minimum flow area positions, each of the vane edges established by the points of maximum thickness of said cross sections lie substantially along planes passing through said longitudinal axis.
Claim 3
Dependent Claim
58 words
The apparatus of claim 1 which includes means for automatically and continuously moving said vanes to selected angular positions between said stowed positions and said minimum flow area positions to continuously change the effective shape and flow area of said passageway to maintain choked flow for sound suppression purposes while supplying the changing airflow requirements of said engine.
Claim 4
Dependent Claim
40 words
The apparatus defined in claim 1 wherein each of the tapered vanes at the end of the vane farthest from said axis of rotation has a cross section with the thickness to chord ratio of a thin transonic airfoil section.
Claim 5
Dependent Claim
46 words
The apparatus defined in claim 3 wherein the chord length of the cross sections of each of said vanes increases uniformly from a minimum at said end of the vane farthest from said axis of rotation to a maximum near the other end of said vane.
Claim 6
Dependent Claim
58 words
The apparatus of claim 2 wherein said means for automatically and continuously moving said vanes comprises: a counter means to measure the speed of revolution of a compressor rotor of said engine, and a hydraulic servovalve responsive to a signal influenced by said counter means for controlling the position of a hydraulic actuator operably connected to said vanes.
References Cited (Backward Citations)
GB921127A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-04 | 1975-04-05 | 1975-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-04 | 1979-04-05 | 1979-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-04 | 1983-04-05 | 1983-10-05 | $7700.00 | Window Closed / Lapsed |