Patent US3621933A successfully refreshed from Google Patents.
US3621933A
Expired / Lapsed
US
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Method and apparatus for suppressing the noise of an aircraft jet engine
Assignee: Rohr Inc
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Filing: 1970-07-27
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Granted: 1971-11-23
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Expires: 1990-07-27
Abstract
Abstract An aircraft jet engine is provided with a semicylindrical reflector/suppressor shield which for takeoff of the aircraft is extended sufficiently downstream of the engine nozzle to intercept the accompanying cone of noise of the jetstream several nozzle diameters aft of the nozzle in the region of the expansion boundary of the jetstream where the noise level is maximum so that such noise which otherwise would be radiated toward the ground is reflected by the shield to thus substantially reduce the effective perceived noise level at the ground. The shield is interrelated structurally and functionally with the engine and nozzle structures so that appropriately configured nozzle and nozzle adjuncts effect stream division, mixing and frequency conversion, ejector action for thrust augmentation at takeoff, and thrust reversal for aircraft braking on landing, all rendered compatible with the operation of the reflector/suppressor shield and the noise abatement provided thereby.
Inventors
- 👤 Burt F Raynes
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:18
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/44
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
171 words
The method of suppressing the noise of an aircraft having a jet engine which comprises: the step preparatory to takeoff of the aircraft of extending a reflector/suppressor shield to a deployed position sufficiently downstream of the engine nozzle to intercept the cone of noise accompanying the jet stream several nozzle diameters aft of the nozzle in the region of the expansion boundary of the jet stream where the noise level is maximum so that such noise which otherwise would be radiated toward the ground is reflected by the reflector/suppressor shield, thereby to reduce substantially the effective perceived noise level at the ground during takeoff, and the step of interposing an ejector barrel between the extended reflector/suppressor shield and the end of the nozzle to provide sound suppression and thrust augmentation by mixing of the ejector-entrained air with the jet stream, and the step after takeoff of withdrawing the reflector/suppressor shield from its deployed position to a stowed position disposed about the nozzle axis and upstream of the end of the nozzle.
Claim 2
Independent Claim
171 words
The method of suppressing the noise of an aircraft having a jet engine which comprises: the step preparatory to takeoff of the aircraft of extending a reflector/suppressor shield to a deployed position sufficiently downstream of the engine nozzle to intercept the cone of noise accompanying the jet stream several nozzle diameters aft of the nozzle in the region of the expansion boundary of the jet stream where the noise level is maximum so that such noise which otherwise would be radiated toward the ground is reflected by the reflector/suppressor shield, thereby to reduce substantially the effective perceived noise level at the ground during takeoff, and the step of interposing an ejector barrel between the extended reflector/suppressor shield and the end of the nozzle to provide sound suppression and thrust augmentation by mixing of the ejector-entrained air with the jet stream, and the step after takeoff of withdrawing the reflector/suppressor shield from its deployed position to a stowed position disposed about the nozzle axis and upstream of the end of the nozzle.
Claim 3
Dependent Claim
50 words
The method as in claim 1 wherein the reflector/suppressor shield is formed as a separable part of the engine housing and the steps of extending and withdrawing the shield include the steps of translating the shield between said stowed and deployed positions thereof and in and out of the housing.
Claim 4
Dependent Claim
26 words
The method as in claim 2 including the step of removing the reflector/suppressor from the engine housing to expose an area of the engine for servicing.
Claim 5
Dependent Claim
82 words
The method as in claim 1 wherein the jet engine has thrust reverser doors for braking of the aircraft on landing and the method includes the steps of moving the doors between stowed and deployed positions thereof wherein the doors in the stowed position are arranged about the engine nozzle, and in the deployed position are extended substantially transversely of the nozzle axis and aft of the nozzle effectively to block and reverse the direction of the jetstream issuing from the nozzle.
Claim 6
Independent Claim
254 words
The method of suppressing the noise of an aircraft jet engine having thrust reverser doors for braking of the aircraft on landing in the method comprises: the step preparatory to takeoff of the aircraft of extending a reflector/suppressor shield to a deployed position sufficiently downstream of the engine nozzle to intercept the cone of noise accompanying the jetstream several nozzle diameters aft of the nozzle in the region of the expansion boundary of the jetstream where the noise level is maxiMum so that such noise which otherwise would be radiated toward the ground is reflected by the reflector/suppressor shield, thereby to reduce substantially the effective perceived noise level at the ground during takeoff, the step after takeoff of withdrawing the reflector/suppressor shield from its deployed position to a stowed position disposed about the nozzle axis and upstream of the end of the nozzle, the steps of moving the doors between stowed and deployed positions thereof wherein the doors in the stowed position are arranged about the engine nozzle, and in the deployed position are extended substantially transversely of the nozzle axis and aft of the nozzle effectively to block and reverse the direction of the jetstream issuing from the nozzle, said reverser doors in said stowed position thereof forming an ejector barrel about the end portion of the nozzle, and the step of passing ejector-entrained slipstream air for mixing with the jetstream to effect sound suppression and thrust augmentation thereby while said reflector/suppressor is in said deployed position thereof during takeoff of the aircraft.
Claim 7
Independent Claim
254 words
The method of suppressing the noise of an aircraft jet engine having thrust reverser doors for braking of the aircraft on landing in the method comprises: the step preparatory to takeoff of the aircraft of extending a reflector/suppressor shield to a deployed position sufficiently downstream of the engine nozzle to intercept the cone of noise accompanying the jetstream several nozzle diameters aft of the nozzle in the region of the expansion boundary of the jetstream where the noise level is maxiMum so that such noise which otherwise would be radiated toward the ground is reflected by the reflector/suppressor shield, thereby to reduce substantially the effective perceived noise level at the ground during takeoff, the step after takeoff of withdrawing the reflector/suppressor shield from its deployed position to a stowed position disposed about the nozzle axis and upstream of the end of the nozzle, the steps of moving the doors between stowed and deployed positions thereof wherein the doors in the stowed position are arranged about the engine nozzle, and in the deployed position are extended substantially transversely of the nozzle axis and aft of the nozzle effectively to block and reverse the direction of the jetstream issuing from the nozzle, said reverser doors in said stowed position thereof forming an ejector barrel about the end portion of the nozzle, and the step of passing ejector-entrained slipstream air for mixing with the jetstream to effect sound suppression and thrust augmentation thereby while said reflector/suppressor is in said deployed position thereof during takeoff of the aircraft.
Claim 8
Dependent Claim
95 words
The method as in claim 5 wherein the engine nozzle is corrugated and the method includes the steps of dividing the jetstream issuing from the nozzle and dividing the air stream drawn into the ejector barrel by the dividing action of the corrugated surfaces internally and externally of the nozzle, thereby to promote mixing of the divided jet and air streams in the deployed position of the reflector/suppressor during takeoff, and also thereby to reduce base drag of the corrugated nozzle by reason of the air flow thereover during the inflight operation of the aircraft.
Claim 9
Dependent Claim
49 words
The method as in claim 1 and including the steps of translating the ejector barrel between stowed and deployed positions thereof wherein the ejector barrel in the stowed position is disposed around the end portion of the nozzle and in the deployed position is disposed downstream of the nozzle.
Claim 10
Dependent Claim
39 words
The method as in claim 7 and including the steps of movably mounting the reflector/suppressor shield on the ejector barrel and translating the same between a stowed position on the ejector barrel and said deployed position extending downstream thereof.
Claim 11
Dependent Claim
38 words
The method as in claim 8 and including the steps of movably mounting a pair of thrust reverser doors on the ejector barrel and moving the doors between stowed and deployed positions during the landing of the aircraft.
Claim 12
Dependent Claim
34 words
The method as in claim 9 and including the steps of translating the ejector barrel and the reflector/suppressor shield to said deployed positions thereof and moving the reverser doors to said deployed positions thereof.
Claim 13
Dependent Claim
54 words
The method as in claim 10 including the steps of mounting the reverser doors as separable portions of the ejector barrel in the stowed position of the doors and extending the doors in deployed position transversely of the jetstream axis and aft of the nozzle so that the jetstream is blocked and reversed thereby.
Claim 14
Dependent Claim
62 words
The method as in claim 1 wherein the end portion of the nozzle is corrugated and wherein the method includes dividing the jetstream and entrained air by the corrugated internal and external surfaces of the nozzle to promote said mixing of the jet and air streams, and also to reduce base drag when the ejector barrel is in the stowed position thereof.
Claim 15
Dependent Claim
160 words
Apparatus for suppressing the noise of an aircraft having a jet engine, said apparatus comprising, in combination, a translatable reflector/suppressor shield which extends in a deployed position thereof into the region of the expansion boundary of the jetstream issuing from the engine nozzle to intercept the accompanying cone of noise arising several nozzle diameters downstream of the nozzle whereby such noise which otherwise would be radiated toward and reach the ground with objectionable intensity during takeoff of the aircraft is reflected upwardly by the shield thereby to reduce substantially the effective perceivEd noise level at the ground, and means for translating the shield between said deployed position and a stowed position wherein the shield is disposed about the axis of the nozzle and upstream of said expansion boundary of the jetstream, and an ejector barrel interposed between the extended shield and nozzle and comprising a part of said means for translating said shield between said stowed and deployed positions thereof.
Claim 16
Dependent Claim
160 words
Apparatus for suppressing the noise of an aircraft having a jet engine, said apparatus comprising, in combination, a translatable reflector/suppressor shield which extends in a deployed position thereof into the region of the expansion boundary of the jetstream issuing from the engine nozzle to intercept the accompanying cone of noise arising several nozzle diameters downstream of the nozzle whereby such noise which otherwise would be radiated toward and reach the ground with objectionable intensity during takeoff of the aircraft is reflected upwardly by the shield thereby to reduce substantially the effective perceivEd noise level at the ground, and means for translating the shield between said deployed position and a stowed position wherein the shield is disposed about the axis of the nozzle and upstream of said expansion boundary of the jetstream, and an ejector barrel interposed between the extended shield and nozzle and comprising a part of said means for translating said shield between said stowed and deployed positions thereof.
Claim 17
Dependent Claim
44 words
Apparatus as in claim 13 wherein the shield is substantially of semicylindrical configuration and forms a separable part of the engine housing in said stowed position of the shield whereby the engine is exposed for servicing when the shield is removed from the housing.
Claim 18
Dependent Claim
81 words
Apparatus as in claim 13 and further comprising a pair of thrust reverser doors movably mounted in stowed position about the end portion of the nozzle on diametrically opposite sides thereof, and, when said shield is in the stowed position thereof, being movable to a deployed position in which the doors extend substantially transversely of the nozzle axis and aft of the end of the nozzle so that the jetstream issuing therefrom is blocked and effectively directed forwardly of the engine.
Claim 19
Dependent Claim
63 words
Apparatus as in claim 13 wherein said shield is substantially of semicylindrical configuration and substantially of same length as said ejector barrel, said apparatus further comprising means for movably mounting the shield on said ejector barrel for translational movement axially thereof, and means on the ejector barrel for moving said shield translationally of the ejector barrel to said deployed position of the shield.
Claim 20
Dependent Claim
50 words
Apparatus as in claim 16 wherein said ejector barrel is translatable from a stowed position surrounding an end portion of the nozzle to said interposed position thereof between the nozzle and shield, and wherein said apparatus further comprises means for translating said ejector between said stowed and interposed positions thereof.
Claim 21
Dependent Claim
68 words
Apparatus as in claim 16 wherein said ejector barrel has a pair of thrust reverser doors separably formed therewith and movable in said interposed position of the ejector to a deployed position extending substantially transversely of the jetstream axis and aft of the end of the nozzle so that the jetstream is effectively blocked by the doors in said deployed position thereof and directed forwardly of the engine.
Claim 22
Dependent Claim
64 words
Apparatus as in claim 17 wherein said end portion of the nozzle is corrugated to cause division of the issuing jetstream and of the air stream drawn into the ejector barrel when said doors are closed, said ejector barrel when in said stowed position thereof also reducing base drag by the air drawn therethrough and passed over the external surface of the corrugated nozzle.
Claim 23
Dependent Claim
32 words
Apparatus as in claim 18, said ejector barrel having inner convergent-divergent surfaces, and the convergent surface portions of said doors having end plate configurations to effect said forward directing of the jetstream.
Claim 24
Dependent Claim
244 words
Apparatus for suppressing the noise of an aircraft having a jet engine, said apparatus comprising, in combination, a translatable reflector/suppressor shield which extends in a deployed position thereof into the region of the expansion boundary of the jetstream issuing from the engine nozzle to intercept the accompanying cone of noise arising several nozzle diameters downstream of the nozzle whereby such noise which otherwise would be radiated toward and reach the ground with objectionable intensity during takeoff of the aircraft is reflected upwardly by the shield thereby to reduce substantially the effective perceived noise level at the ground, means for translating the shield between said deployed position and a stowed position wherein the shield is disposed about the axis of the nozzle and upstream of said expansion boundary of the jetstream stream, a pair of thrust reverser doors movably mounted in stowed position about the end portion of the nozzle on diametrically opposite sides thereof and, when said sHield is in the stowed position thereof, being movable to a deployed position in which the doors extend substantially transversely of the nozzle axis and aft of the end of the nozzle so that the jet stream issuing therefrom is blocked and effectively directed forwardly of the engine, and said reverser doors in the stowed position thereof forming an ejector barrel around said end portion of the nozzle, thereby to entrain slipstream air for mixing with the jetstream to provide sound suppression and thrust augmentation during takeoff.
Claim 25
Dependent Claim
244 words
Apparatus for suppressing the noise of an aircraft having a jet engine, said apparatus comprising, in combination, a translatable reflector/suppressor shield which extends in a deployed position thereof into the region of the expansion boundary of the jetstream issuing from the engine nozzle to intercept the accompanying cone of noise arising several nozzle diameters downstream of the nozzle whereby such noise which otherwise would be radiated toward and reach the ground with objectionable intensity during takeoff of the aircraft is reflected upwardly by the shield thereby to reduce substantially the effective perceived noise level at the ground, means for translating the shield between said deployed position and a stowed position wherein the shield is disposed about the axis of the nozzle and upstream of said expansion boundary of the jetstream stream, a pair of thrust reverser doors movably mounted in stowed position about the end portion of the nozzle on diametrically opposite sides thereof and, when said sHield is in the stowed position thereof, being movable to a deployed position in which the doors extend substantially transversely of the nozzle axis and aft of the end of the nozzle so that the jet stream issuing therefrom is blocked and effectively directed forwardly of the engine, and said reverser doors in the stowed position thereof forming an ejector barrel around said end portion of the nozzle, thereby to entrain slipstream air for mixing with the jetstream to provide sound suppression and thrust augmentation during takeoff.
Claim 26
Dependent Claim
53 words
Apparatus as in claim 17 wherein said end portion of the nozzle is corrugated to divide said jet stream and said entrained air, thereby to promote mixing of said divided jet and air streams during takeoff, and also to reduce base drag of the corrugated nozzle during the inflight operation of the aircraft.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-22 | 1975-05-24 | 1975-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-22 | 1979-05-24 | 1979-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-22 | 1983-05-24 | 1983-11-23 | $7700.00 | Window Closed / Lapsed |