Patent US3765623A successfully refreshed from Google Patents.
US3765623A
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Air inlet
Assignee: McDonnell Douglas Corp
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Filing: 1971-10-04
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Granted: 1973-10-16
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Expires: 1991-10-04
Abstract
Abstract A generally circular air inlet for a pylon mounted aircraft jet engine wherein predetermined minimum lip thickness ratios are distributed around the inlet periphery in order to minimize the flow distortion caused by flow separation during certain design operating conditions.
Inventors
- 👤 J Donelson
- 👤 W Douglas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:02
CPC Classifications
F; F02; F02C; F02C7/00; F02C7/04; B; B64; B64D; B64D33/00; B64D33/02; B64D2033/0266; B64D2033/0286; Y; Y10; Y10T; Y10T137/00; Y10T137/0536
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
188 words
A generally cylindrical air inlet for ducting air to a subsonic aircraft''s forward facing jet engine, said inlet including: a generally ring shaped highlight lying generally in a plane; a generally circular throat portion defining a minimum crosssectional area of said inlet; and a smoothly curved inner air inlet surface which extends from said highlight to said throat portion, said surface defining the center line of said inlet centered therein, the distance from said center line to said highlight defining R at any point about the periphery of said highlight and the distance between a tangent to said inner surface at said throat and a parallel to said center line passing through said highlight defining y, said inlet being constructed so the ratio y/R varies in a predetermined manner about the periphery of said inlet to prevent airflow separation during adverse operating conditions, said variation in a predetermined manner being so the ratio y/R is larger at radial segments of said air inlet subjected to the greatest relative wind angles to said center line than at radial segments of said air inlet subjected to lesser relative wind angles.
Claim 2
Dependent Claim
188 words
A generally cylindrical air inlet for ducting air to a subsonic aircraft''s forward facing jet engine, said inlet including: a generally ring shaped highlight lying generally in a plane; a generally circular throat portion defining a minimum crosssectional area of said inlet; and a smoothly curved inner air inlet surface which extends from said highlight to said throat portion, said surface defining the center line of said inlet centered therein, the distance from said center line to said highlight defining R at any point about the periphery of said highlight and the distance between a tangent to said inner surface at said throat and a parallel to said center line passing through said highlight defining y, said inlet being constructed so the ratio y/R varies in a predetermined manner about the periphery of said inlet to prevent airflow separation during adverse operating conditions, said variation in a predetermined manner being so the ratio y/R is larger at radial segments of said air inlet subjected to the greatest relative wind angles to said center line than at radial segments of said air inlet subjected to lesser relative wind angles.
Claim 3
Dependent Claim
65 words
The air inlet defined in claim 1 wherein the uppermost portion of said air inlet in its normal orientation, is defined as the 0*-360* point thereof and the point thereof 90* from the 0*-360* point toward the center-line of the aircraft is defined as the 270* point thereof, said ratio y/R being minimum about the 0*-360* point, and maximum about the 90* and 270* points.
Claim 4
Dependent Claim
34 words
The air inlet defined in Claim 2 wherein said ratio y/R is greater at the 90* and 270* points than at the 0*-360* point and said ratio y/R is maximum at the 180* point.
Claim 5
Dependent Claim
39 words
The air inlet defined in claim 2 wherein said ratio y/R is greater at the 180* point than at the 0*-360* point and said ratio Y/R is greater at the 90* and 270* points than at the 180* point.
Claim 6
Dependent Claim
88 words
The air inlet defined in claim 1 wherein said air inlet is spaced from and mounted to the side of the aircraft fuselage, the uppermost portion of said air inlet in its normal orientation being defined as the 0*-360* point thereof and the point thereof 90* from the 0*-360* point toward the centerline of the fuselage being defined as the 270* point thereof, said ratio y/R being minimum on the upper portion of said inlet generally between the 270* to 90* points and maximum about the 180* point.
Claim 7
Dependent Claim
82 words
The air inlet defined in claim 1 wherein said air inlet is spaced from and mounted to the side of the aircraft fuselage, the uppermost portion of said air inlet in its normal orientation being defined as the 0*-360* point thereof and the point thereof 90* from the 0*-360* point toward the centerline of the fuselage being defined as the 270* point thereof, said ratio y/R being maximum between the 0*-360* and 90* points and minimum between the 180* and 270* points.
Claim 8
Dependent Claim
53 words
The air inlet defined in claim 1 wherein said air inlet is spaced from and mounted above the aircraft fuselage, the uppermost portion of said air inlet being defined as the 0*-360* point, said ratio y/R being minimum at the 0*-360* and 180* points and being maximum at the 90* and 270* points.
Claim 9
Dependent Claim
14 words
The air inlet defined in claim 1 wherein said ratio varies at least 0.01.
Claim 10
Dependent Claim
40 words
The air inlet defined in claim 1 wherein said lip thickness ratio is greater than a predetermined minimum thickness at the lower portion of said inlet to protect against separation due to a positive angle of attack of the aircraft.
Claim 11
Dependent Claim
30 words
The air inlet defined in claim 1 wherein said lip thickness ratio is greater than a predetermined mimimum thickness at the sides thereof to protect against separation due to crosswinds.
References Cited (Backward Citations)
US3033491A
Cited
US3583661A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |