US4371132A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reversible thrust ducted fan propulsion unit
Assignee: Rolls Royce PLC
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Filing: 1981-01-12
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Granted: 1983-02-01
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Expires: 2001-01-12
Abstract
Abstract Ducted fan propulsion unit for aircraft has a main duct 3 containing a reversible pitch fan 1 rearward of which is provided a flow splitter 13 dividing the main duct into radially outer and inner branch ducts 3A, 3B. A radial passage 15 in the splitter connects the branch ducts and divides the splitter into front and rear parts 13A, 13B. The part of the inner branch duct forward of the radial passage contains an array of stator vanes 12B and has outer and inner wall surfaces 3B1,3B2 both of progressively reducing diameter to urge the flow through that branch duct toward the inlet of a compressor 8 of yet smaller diameter. Stator vanes 12A in the outer branch duct are arranged forward of the radial passage. The arrangement favors a relatively low axial length of the powerplant.
Inventors
- 👤 Clifford S. Woodward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:24
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/54; F02K1/64; F02K1/70; F02K1/72; F02K1/66
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
219 words
A ducted fan propulsion unit for aircraft comprising an annular main duct, a fan contained within the main duct and having blades the pitch of which is reversible, a first opening defined in the duct forward of the fan, an annular flow splitter situated rearward of the fan and dividing the main duct into radially outer and inner branch ducts, a passage extending radially through the splitter to connect the branch ducts, outer stator vanes provided in the outer branch duct forward of said passage, inner stator vanes provided in the inner branch duct forward of said passage, a second opening defined in the outer branch duct rearward of the stator vanes therein, wherein the part of the inner branch duct lying forward of the passage is defined by radially outer and inner surfaces configured so there is a progressively rearwardly reducing diameter of said inner duct, and wherein the part of the inner duct rearward of said passage is defined by outer and inner surfaces configured so there is a progressively rearwardly reducing diameter and leading to a compressor of a gas turbine engine for driving the fan, said radially outer surface of said inner duct forward of said passage being shaped so as to urge the air flow in said inner duct in a radially inward direction.
Claim 2
Dependent Claim
219 words
A ducted fan propulsion unit for aircraft comprising an annular main duct, a fan contained within the main duct and having blades the pitch of which is reversible, a first opening defined in the duct forward of the fan, an annular flow splitter situated rearward of the fan and dividing the main duct into radially outer and inner branch ducts, a passage extending radially through the splitter to connect the branch ducts, outer stator vanes provided in the outer branch duct forward of said passage, inner stator vanes provided in the inner branch duct forward of said passage, a second opening defined in the outer branch duct rearward of the stator vanes therein, wherein the part of the inner branch duct lying forward of the passage is defined by radially outer and inner surfaces configured so there is a progressively rearwardly reducing diameter of said inner duct, and wherein the part of the inner duct rearward of said passage is defined by outer and inner surfaces configured so there is a progressively rearwardly reducing diameter and leading to a compressor of a gas turbine engine for driving the fan, said radially outer surface of said inner duct forward of said passage being shaped so as to urge the air flow in said inner duct in a radially inward direction.
Claim 3
Dependent Claim
80 words
Unit according to claim 1 wherein the splitter comprises a front and a rear part spaced apart axially so as to define said passage therebetween, and wherein said front part is so positioned and shaped in relation to the rear part that air flowing rearwards over the splitter crosses the passage along a flow line smoothly connecting the radially outer surfaces of the splitter parts and along a flow line smoothly connecting the radially inner surfaces of the splitter parts.
Claim 4
Dependent Claim
39 words
A unit according to claim 1 or 2, wherein said second opening and said passage are substantially in radial alignment so that the air flowing through the second opening and toward the passage may have a significant radial component.
References Cited (Backward Citations)
US3303653A
Cited
US3494129A
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US3820719A
Cited
US4047911A
Cited
US4005574A
Cited
US4055042A
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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) | 1986-01-31 | 1986-08-02 | 1987-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-31 | 1990-08-02 | 1991-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-31 | 1994-08-02 | 1995-02-01 | $7700.00 | Window Closed / Lapsed |