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US3664455A Expired / Lapsed US ⏱️ 0.0 years remaining

Twisted vane sound suppressor for aircraft jet engine

Assignee: Rohr Inc
•
Filing: 1971-03-15
•
Granted: 1972-05-23
•
Expires: 1991-03-15
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Abstract

Abstract A plurality of vanes, each twisted about a longitudinal axis, and of airfoil sectional shape, are mounted peripherally about the exit end of a jet engine duct from which a jet exhaust stream is discharged. Control means adjust the vanes about their longitudinal axis from stowed position with their leading ends substantially tangent to the edge portion of the duct upon which they are mounted, to deployed position with their leading ends disposed substantially radially of such duct. In their stowed position the vanes cause minimum mixing of the jet stream gases with the surrounding ambient air, while in their deployed position the outer portions of the vanes project into the surrounding ambient air, and their inner portions project into the jet exhaust stream to cause a substantial but smooth intermixing of such gases, thereby tending to reduce noise producing turbulence.

Inventors

  • 👤 Tirumalesa Duvvuri

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 05:03
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/46

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 144 words
Sound attenuating mechanism for an aircraft jet engine having an annular wall defining an exhaust duct through the exit end of which is discharged a jet stream of exhaust gases, said mechanism comprising: a plurality of helically twisted vanes mounted in spaced relation peripherally about, and directly aft of, the exit end of said duct wall, thereby positioning said vanes in the boundary layer between the jet exhaust stream and surrounding gas envelope, means mounting each vane for rotative adjustment about its helical axis, such helical axis being disposed longitudinally of the duct, and vane actuating means operatively connected to move said vanes in unison, rotatively about their respective helical axes, between stowed position with the upstream edge of each vane substantially tangent to the duct wall, and deployed position with the upstream edge of each vane disposed substantially radially of such duct wall.
Claim 2
Dependent Claim 144 words
Sound attenuating mechanism for an aircraft jet engine having an annular wall defining an exhaust duct through the exit end of which is discharged a jet stream of exhaust gases, said mechanism comprising: a plurality of helically twisted vanes mounted in spaced relation peripherally about, and directly aft of, the exit end of said duct wall, thereby positioning said vanes in the boundary layer between the jet exhaust stream and surrounding gas envelope, means mounting each vane for rotative adjustment about its helical axis, such helical axis being disposed longitudinally of the duct, and vane actuating means operatively connected to move said vanes in unison, rotatively about their respective helical axes, between stowed position with the upstream edge of each vane substantially tangent to the duct wall, and deployed position with the upstream edge of each vane disposed substantially radially of such duct wall.
Claim 3
Dependent Claim 25 words
Sound attenuating mechanism as claimed in claim 1 wherein operation of the vane actuating means moves all of the vanes rotatively in the same direction.
Claim 4
Dependent Claim 25 words
Sound attenuating means as claimed in claim 1 wherein operation of the vane actuating means moves alternate ones of the vanes rotatively in opposite directions.
Claim 5
Dependent Claim 24 words
Sound attenuating means as claimed in claim 1 wherein the vanes are of airfoil shape in the direction of gas flow past the vanes.

References Cited (Backward Citations)

US3153319A Cited
US2934889A Cited
GB885093A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1975-05-23 1975-11-22 1976-05-23 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1979-05-23 1979-11-22 1980-05-23 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1983-05-23 1983-11-22 1984-05-23 $7700.00 Window Closed / Lapsed

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