Patent US3655007A successfully refreshed from Google Patents.
US3655007A
Expired / Lapsed
US
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Sound suppression system for jet engine
Assignee: Rohr Inc
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Filing: 1970-09-11
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Granted: 1972-04-11
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Expires: 1990-09-11
Abstract
Abstract System is intended for use with a jet engine and comprises an elongate suppressor panel which is connected to the aft end of the nozzle and extends rearward. The panel is generally rectilinear in longitudinal section and concavo-convex in transverse cross section with its concave face directed upward. The panel is generally centered in the jet stream to divide it into upper and lower portions of generally equal volume. The panel serves as a shield against downward radiation of sound waves from the upper portion of the stream and reflects them upward in a converging pattern. The convex lower face of the panel reflects the sound waves from the lower portion of the stream downward but at the same time disperses them laterally so that the unit sound intensity at the ground is substantially reduced. The noise level at the suppressor is initially substantially reduced by making the panel of a very efficient sound absorbing material such as a honeycomb core with a porous skin. The system also includes a thrust reverser. A support panel extends upward from the suppressor panel and carries a pair of blocker doors which swing laterally to block aft flow of the upper portion of the jet stream, and a single blocker door is mounted in the suppressor panel and swings downward to block aft flow of the lower portion of the jet stream. The reversing forces above and below the nozzle axis balance out the directional moments and avoid instability.
Inventors
- 👤 Jack H Hilbig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:25
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/44; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
163 words
A sound suppression system for use in combination with a jet engine having a rearwardly discharging exhaust gas nozzle, comprising: an elongate suppressor panel connected to the aft end of the nozzle and extending rearwardly therefrom; the panel being generally rectilinear in longitudinal section and concavo-convex in transverse cross section with its concave face directed upward and its convex face directed downward; the panel being generally centered in the exhaust jet stream at the exit plane of the nozzle to divide the stream into upper and lower portions of generally equal volume, the panel serving as a shield against radiation of sound waves downward from the upper portion of the jet stream; the concave upper face of the panel reflecting sound waves from the upper portion of the jet stream upwardly and concentrating them; and the convex lower face of the panel reflecting sound waves from the lower portion of the jet stream downwardly and dispersing them laterally to reduce the unit intensity.
Claim 2
Dependent Claim
163 words
A sound suppression system for use in combination with a jet engine having a rearwardly discharging exhaust gas nozzle, comprising: an elongate suppressor panel connected to the aft end of the nozzle and extending rearwardly therefrom; the panel being generally rectilinear in longitudinal section and concavo-convex in transverse cross section with its concave face directed upward and its convex face directed downward; the panel being generally centered in the exhaust jet stream at the exit plane of the nozzle to divide the stream into upper and lower portions of generally equal volume, the panel serving as a shield against radiation of sound waves downward from the upper portion of the jet stream; the concave upper face of the panel reflecting sound waves from the upper portion of the jet stream upwardly and concentrating them; and the convex lower face of the panel reflecting sound waves from the lower portion of the jet stream downwardly and dispersing them laterally to reduce the unit intensity.
Claim 3
Dependent Claim
38 words
A system as claimed in claim 1; the forward end of the panel extending into the aft portion of the nozzle to segregate the upper and lower portions of the jet stream prior to discharge from the nozzle.
Claim 4
Dependent Claim
15 words
A system as claimed in claim 1; the panel being provided with sound absorbing surfaces.
Claim 5
Dependent Claim
40 words
A system as claimed in claim 1; the panel comprising a hollow core containing a multiplicity of discrete sound absorbing cells; and a skin overlying the cells and provided with a multiplicity of apertures therethrough in communication with the cells.
Claim 6
Dependent Claim
29 words
A system as claimed in claim 1; the length of the panel aft of the nozzle being ag least twice the diameter of the nozzle at its exit plane.
Claim 7
Dependent Claim
34 words
A system as claimed in claim 1; the length of the panel aft of the nozzle being in the range of two to six times the diameter of the nozzle at its exit plane.
Claim 8
Dependent Claim
42 words
A system as claimed in claim 1; the side edges of the panel diverging reward generally along the marginal stream lines of the jet expansion flow for a distance at least equal to the diameter of the nozzle at its exit plane.
Claim 9
Dependent Claim
23 words
A system as claimed in claim 7; the trailing edge of the panel converging rearward along lines generally corresponding the jet velocity profile.
Claim 10
Dependent Claim
17 words
A system as claimed in claim 1; the cross sectional shape of the panel being generally arcuate.
Claim 11
Dependent Claim
22 words
A system as claimed in claim 1; the cross sectional shape of the panel being generally in the form of a V.
Claim 12
Dependent Claim
51 words
A system as claimed in claim 1; the aft portion of the nozzle above the panel being generally arcuate; and the aft portion of the nozzle below the panel being fluted to define a plurality of lobes for mixing free stream air with the gas to further reduce the noise level.
Claim 13
Dependent Claim
43 words
A system as claimed in claim 1; and a plurality of blockers carried by the panel and swingable between stowed position parallel to the jet stream and deployed position diverging forward to deflect the jet stream laterally and forwardly and produce reverse thrust.
Claim 14
Dependent Claim
45 words
A system as claimed in claim 12; including a blocker door pivotally mounted adjacent to its aft end to the panel about a transverse axis and swingable from stowed position substantially flush with the lower surface of the panel downward to deployed position diverging forward.
Claim 15
Dependent Claim
28 words
A system as claimed in claim 12; the panel having a blocker-receiving opening therein, and at least one of the blockers in stowed position fitting into the opening.
Claim 16
Dependent Claim
71 words
A system as claimed in claim 12; including a support panel connected to the suppressor panel and extending upward therefrom in a substantially vertical fore and aft plane containing the axis of the nozzle; and a pair of blocker doors pivotally mounted adjacent to their aft ends to the support panel and swingable laterally from stowed position substantially flush with the faces of the support panel to deployed position diverging forward.
Claim 17
Dependent Claim
27 words
A system as claimed in claim 15; the support panel having a door receiving opening therein and the blocker doors in stowed position fitting into the opening.
Claim 18
Independent Claim
63 words
A method of suppressing the sound of the exhaust jet stream from a jet engine, comprising: segregating the stream longitudinally into upper and lower portions; directing upwardly substantially all of the sound waves emitted by the upper portion; directing downwardly substantially of the sound waves emitted by the lower portion; and dispersing the downwardly directed sound waves laterally to reduce their unit intensity.
Claim 19
Independent Claim
63 words
A method of suppressing the sound of the exhaust jet stream from a jet engine, comprising: segregating the stream longitudinally into upper and lower portions; directing upwardly substantially all of the sound waves emitted by the upper portion; directing downwardly substantially of the sound waves emitted by the lower portion; and dispersing the downwardly directed sound waves laterally to reduce their unit intensity.
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) | 1975-04-11 | 1975-10-11 | 1976-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-11 | 1979-10-11 | 1980-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-11 | 1983-10-11 | 1984-04-11 | $7700.00 | Window Closed / Lapsed |