US3815360A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combined infrared and sound suppressor for aircraft jet engine
Assignee: Rohr Inc
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Filing: 1971-04-16
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Granted: 1974-06-11
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Expires: 1991-04-16
Abstract
Abstract For reducing line-of-sight, infrared radiation and exhaust noise from the tailpipe of a jet aircraft engine, a plurality of hollow helical vanes with porous walls and supplied internally with pressurized coolant fluid are mounted co-axially and in symmetrically distributed arrangement, within a hollow tailpipe, the inner wall of which is also porous. Each vane has circumferential extent within the tailpipe sufficient to completely mask line-of-sight exposure into the engine from any point aft of the plane of the exit end of the tailpipe and to provide acoustic baffling and swirl for external mixing. Where the engine has an axial tail cone or bullet, the inner edges of the vanes may define a hollow axial core equal in diameter to the bullet.
Inventors
- 👤 J Wellinitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:52
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/38; F02K1/383; F02K1/46; F02K1/78; F02K1/82; F02K1/822; F02K1/825
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
178 words
An infrared and sound suppressor for an aircraft jet engine having a turbine casing with annular aft end through which the turbine exhaust gases exit, said mechanism comprising a hollow wall tailpipe adated to be mounted co-axially and coextensively on the aft end of the turbine casing of an engine for which the mechanism is designed, said tailpipe comprising an impervious outer wall and a porous inner wall spaced therefrom, a plurality of hollow, porous wall, helical vanes fitted coaxially in symmetrically spaced relation into the tailpipe and sealed thereto, each vane having an open, radially outward base communicating the hollow interior of each vane with the hollow interior of the tailpipe, a duct adapted to be connected with a supply of coolant fluid at a pressure greater than that within the tailpipe, and openly communicating with the hollow interior of the tailpipe, and thence with the hollow interiors of the vanes for transpiration of coolant fluid from the duct through, and flow along, the porous walls of the tailpipe and vanes into the interior of the tailpipe.
Claim 2
Dependent Claim
178 words
An infrared and sound suppressor for an aircraft jet engine having a turbine casing with annular aft end through which the turbine exhaust gases exit, said mechanism comprising a hollow wall tailpipe adated to be mounted co-axially and coextensively on the aft end of the turbine casing of an engine for which the mechanism is designed, said tailpipe comprising an impervious outer wall and a porous inner wall spaced therefrom, a plurality of hollow, porous wall, helical vanes fitted coaxially in symmetrically spaced relation into the tailpipe and sealed thereto, each vane having an open, radially outward base communicating the hollow interior of each vane with the hollow interior of the tailpipe, a duct adapted to be connected with a supply of coolant fluid at a pressure greater than that within the tailpipe, and openly communicating with the hollow interior of the tailpipe, and thence with the hollow interiors of the vanes for transpiration of coolant fluid from the duct through, and flow along, the porous walls of the tailpipe and vanes into the interior of the tailpipe.
Claim 3
Dependent Claim
71 words
An infrared and sound suppressor as claimed in claim 1 wherein a plurality of spiral rows of holes are provided in the porous inner wall of the tailpipe, and the open base of each vane is fitted to cover one of such rows of holes to facilitate the flow of coolant fluid from the hollow interior of the tailpipe through such holes into the hollow interior of each of the vanes.
Claim 4
Dependent Claim
21 words
An infrared and sound suppressor as claimed in claim 1 wherein each helical vane has a circumferential extent greater than 180*.
Claim 5
Dependent Claim
23 words
An infrared and sound suppressor as claimed in claim 1 wherein each helical vane has a circumferential extent of the order of 240*.
Claim 6
Dependent Claim
66 words
An infrared and sound suppressor as claimed in claim 1 wherein the suppressor is designed for an engine provided with a conventional bullet mounted co-axially of the aft end of the turbine casing and the helical vanes of tHe suppressor terminate at their radially inward edges a radial distance from the axis of the tailpipe not greater than the radius of the bullet on such engine.
Claim 7
Dependent Claim
33 words
An infrared and sound suppressor as claimed in claim 1 wherein the radially inward edge of each helical vane terminates short of the axis of tailpipe to provide an open axial passage therethrough.
Claim 8
Dependent Claim
24 words
An infrared and sound suppressor as claimed in claim 6 wherein the radially inward edge of each helical vane is a relatively sharp edge.
Claim 9
Dependent Claim
21 words
An infrared and sound suppressor as claimed in claim 7 wherein the upstream edge of each helical vane is also sharpened.
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) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |