US3729934A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas turbine engines
Assignee: UK Secretary of State for Defence
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Filing: 1971-11-08
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Granted: 1973-05-01
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Expires: 1991-11-08
Abstract
Abstract A turbo-fan engine having four blades capable of being turned from a forward thrust-producing position to a reverse thrust position, also includes means for biassing the flow through the fan in the reverse thrust mode of operation towards the engine axis, to reduce the base drag due to low pressure air on the engine axis, and to prevent attachment of the flow to the fan intake lip.
Inventors
- 👤 R Denning
- 👤 R Wiltshire
- 👤 C Woodward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:05
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/54; F02K1/64; F02K1/66
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
97 words
A gas turbine jet propulsion engine comprising a gas generator, a fan including a ring of fan blades, an annular duct, means mounting the fan for operation in the duct and shafting by means of which the fan is driven from the gas generator, the fan blades being individually rotatable about their longitudinal axes from a forward thrust-producing position to a reverse thrust producing-position, and wherein the improvement comprises means, operable when the fan blades are in the reverse thrust-producing position, for biassing the air flow emerging forwardly from the fan towards the axis of the engine.
Claim 2
Dependent Claim
97 words
A gas turbine jet propulsion engine comprising a gas generator, a fan including a ring of fan blades, an annular duct, means mounting the fan for operation in the duct and shafting by means of which the fan is driven from the gas generator, the fan blades being individually rotatable about their longitudinal axes from a forward thrust-producing position to a reverse thrust producing-position, and wherein the improvement comprises means, operable when the fan blades are in the reverse thrust-producing position, for biassing the air flow emerging forwardly from the fan towards the axis of the engine.
Claim 3
Dependent Claim
38 words
A gas turbine engine according to claim 1 and wherein the means for biassing said air flow towards the axis of the engine comprises means for ejecting air under pressure from at least one wall of the duct.
Claim 4
Dependent Claim
30 words
A gas turbine engine according to claim 2 and wherein the air under pressure is admitted into the duct through apertures in said at least one wall of the duct.
Claim 5
Dependent Claim
102 words
A gas turbine engine according to claim 1 and wherein the means for biassing the air flow from the fan towards the axis of the engine comprises a flap, a pivot by which the flap is pivotably mounted at its rearward end to the internal surface of the outer wall of the duct, said flap forming part of said surface during the forward thrust mode of operation of the fan, but which lies obliquely of the air flow in the duct during the reverse thrust mode of operation of the fan, and deflects said air flow towards the axis of the engine.
Claim 6
Dependent Claim
31 words
A gas turbine engine according to claim 4 and wherein means are additionally provided for admitting air under pressure through apertures in one or both of the walls of the duct.
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) | 1976-04-30 | 1976-10-30 | 1977-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-30 | 1980-10-30 | 1981-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-30 | 1984-10-30 | 1985-05-01 | $7700.00 | Window Closed / Lapsed |