US4171183A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-bladed, high speed prop-fan
Assignee: RTX Corp
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Filing: 1976-09-24
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Granted: 1979-10-16
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Expires: 1996-09-24
Abstract
Abstract A small diameter, highly loaded multiple bladed variable pitch propulsor having swept blades with thin advanced airfoil sections, integrated with a nacelle contoured to retard the airflow through the blades thereby reducing compressibility losses and designed to operate with a turbine engine and using a single stage reduction gear resulting in a high performance, lightweight propulsion system providing a substantial improvement in efficiency over the high bypass ratio turbofan engine.
Inventors
- 👤 Robert W. Cornell
- 👤 Carl Rohrbach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:50
CPC Classifications
B; B64; B64C; B64C11/00; B64C11/02; B64C11/14; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
120 words
A small diameter multi-blade prop-fan integrated system having: from 6 to 12 short blades thereon of a length to make a fan of from about 10 to 14 feet in diameter, each blade having a very thin airfoil shape based on the blade length, the major portion of the blade being from about 2-4% thick, each blade being swept at the tip, said blades having a variable pitch, a large diameter hub on which said blades are mounted for pitch changes, a large diameter spinner surrounding the hub, and a nacelle back of the spinner and forming an extension thereof, said spinner and nacelle being contoured to produce a subsonic flow of air between the blades adjacent the bases thereof.
Claim 2
Dependent Claim
120 words
A small diameter multi-blade prop-fan integrated system having: from 6 to 12 short blades thereon of a length to make a fan of from about 10 to 14 feet in diameter, each blade having a very thin airfoil shape based on the blade length, the major portion of the blade being from about 2-4% thick, each blade being swept at the tip, said blades having a variable pitch, a large diameter hub on which said blades are mounted for pitch changes, a large diameter spinner surrounding the hub, and a nacelle back of the spinner and forming an extension thereof, said spinner and nacelle being contoured to produce a subsonic flow of air between the blades adjacent the bases thereof.
Claim 3
Dependent Claim
37 words
A prop-fan as in claim 1 in which the diameter of the propeller is approximately 60% that of a conventional propeller and the spinner immediately upstream of the blade is about one-quarter the diameter of the prop-fan.
Claim 4
Dependent Claim
56 words
A prop-fan as in claim 2 in which the diameter of the nacelle immediately downstream of the blades is about 35% of the diameter of the propeller and the spinner and nacelle are contoured to reduce the effective Mach number of the airflow to less than the critical Mach number of the blade airfoils adjacent thereto.
Claim 5
Dependent Claim
100 words
A prop-fan for use with a turbine engine, said propeller having: a large number of relatively short blades having inner end retentions and tips, a hub in which the blades are mounted, a spinner surrounding the hub, a nacelle back of the spinner and merging therewith, each of said blades having a very thin airfoil shape and each blade being swept over the outer portion of the blade length, with the sweep increasing toward the blade tip, and said nacelle and spinner being so contoured as to reduce the velocity of the air flowing between the blades adjacent the nacelle.
Claim 6
Dependent Claim
100 words
A prop-fan for use with a turbine engine, said propeller having: a large number of relatively short blades having inner end retentions and tips, a hub in which the blades are mounted, a spinner surrounding the hub, a nacelle back of the spinner and merging therewith, each of said blades having a very thin airfoil shape and each blade being swept over the outer portion of the blade length, with the sweep increasing toward the blade tip, and said nacelle and spinner being so contoured as to reduce the velocity of the air flowing between the blades adjacent the nacelle.
Claim 7
Dependent Claim
43 words
A prop-fan as in claim 4 in which the blades have a length such that the effective velocity of the air at the blade tip when the fan is in use is no greater than the critical Mach number of the airfoil sections.
Claim 8
Dependent Claim
117 words
A prop-fan for use with a turbine engine in aircraft, said prop-fan having: a large number of relatively short blades having inner end retentions and tips, a large diameter hub in which the blade retentions are mounted for rotation, substantially on the radial axis of the blade, a spinner surrounding the hub, a nacelle back of the spinner and merging therewith, each of said blades having a very thin airfoil shape in cross section, each blade being swept for the outer portion of each blade, this sweep increasing toward the blade tip to as much as a 30° sweep at the tip, and means for adjusting the pitch of all the blades in unison in the hub.
Claim 9
Dependent Claim
117 words
A prop-fan for use with a turbine engine in aircraft, said prop-fan having: a large number of relatively short blades having inner end retentions and tips, a large diameter hub in which the blade retentions are mounted for rotation, substantially on the radial axis of the blade, a spinner surrounding the hub, a nacelle back of the spinner and merging therewith, each of said blades having a very thin airfoil shape in cross section, each blade being swept for the outer portion of each blade, this sweep increasing toward the blade tip to as much as a 30° sweep at the tip, and means for adjusting the pitch of all the blades in unison in the hub.
Claim 10
Dependent Claim
39 words
A prop-fan as in claim 6 in which the nacelle and spinner are contoured to be about one-fourth the diameter of the fan in the region of the blades and about three-eighths of the diameter downstream of the blades.
Claim 11
Dependent Claim
121 words
A propulsion system for a turbine engine having a power turbine including a prop-fan comprising: a large number of relatively short blades having inner ends and outer tips, a large diameter hub engaging the inner ends of the blades and supporting said blades for variable pitch, the hub and blades having a diameter of from 10 to 14 feet, each of said blades having a very thin airfoil shape in cross section having a thickness ratio of about 2 to 4% for a major portion of the length from the tip, each blade being swept for the outer portion of the blade, and said prop-fan being in combination with a single stage gear reduction system driven directly from the power turbine.
Claim 12
Dependent Claim
121 words
A propulsion system for a turbine engine having a power turbine including a prop-fan comprising: a large number of relatively short blades having inner ends and outer tips, a large diameter hub engaging the inner ends of the blades and supporting said blades for variable pitch, the hub and blades having a diameter of from 10 to 14 feet, each of said blades having a very thin airfoil shape in cross section having a thickness ratio of about 2 to 4% for a major portion of the length from the tip, each blade being swept for the outer portion of the blade, and said prop-fan being in combination with a single stage gear reduction system driven directly from the power turbine.
Claim 13
Dependent Claim
21 words
A propulsion system as in claim 8 in which the prop-fan diameter is about 60% that of a comparable conventional propeller.
Claim 14
Dependent Claim
61 words
A propulsion system as in claim 9 in which the prop-fan has a spinner surrounding the hub and a nacelle back of the hub, and the spinner and nacelle are contoured to reduce the velocity of the air flowing over the portion of the blades adjacent thereto to less than the critical Mach number of the blade airfoils in this area.
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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) | 1982-10-15 | 1983-04-16 | 1983-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-10-15 | 1987-04-16 | 1987-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-10-15 | 1991-04-16 | 1991-10-16 | $7700.00 | Window Closed / Lapsed |