# US 12,215,607 B1 · Unducted turbine engine comprising stator blades having different chords

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- Number: US 12,215,607 B1
- Document ID: US12215607B1
- Status: Granted
- Kind: B1
- Application number: 18/718,654
- Filed: 2022-12-12
- Published: 2025-02-06
- Granted: 2025-02-04
- Earliest claimed: 2021-12-13
- Assignees: Safran Aircraft Engines
- Applicants: Safran Aircraft Engines
- Inventors: Eva Julie Lebeault; Laurent Soulat
- Web page: https://patentgrep.com/patent/US12215607B1

## CPC

- F01D 9/041: {using blades (F01D5/148 takes precedence)}
- B64C 11/20: Constructional features
- F01D 5/142: {of the blades of successive rotor or stator blade-rows}
- F02C 6/206: {the vehicles being airscrew driven}
- F02K 3/02: in which part of the working fluid by-passes the turbine and combustion chamber
- B64C 11/08: for non-adjustable blades
- F02C 7/20: Mounting or supporting of plant; Accommodating heat expansion or creep
- F05D 2220/325: to drive unshrouded, high solidity propeller
- F05D 2260/961: by mistuning rotor blades or stator vanes with irregular interblade spacing, airfoil shape
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- B64C: AEROPLANES; HELICOPTERS
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

An aircraft including at least one unducted turbine engine for the propulsion of the aircraft. The turbine engine comprising: a rotor and a stator comprising a plurality of stator blades extending radially with respect to the longitudinal axis, each stator blade being defined, in a plane transverse to the longitudinal axis, by an angular position; and at least one aerodynamic obstruction positioned close to the turbine engine. The stator of the turbine engine comprises stator blades having a first chord, referred to as conventional blades, and at least one stator blade having a second chord larger than the first chord, referred to as the elongate blade, said at least one elongate blade being positioned in an interference angular range defined opposite the aerodynamic obstacle, so as to increase the straightening of the airflow from the rotor in the interference angular range.

## Claims

### Claim 1

An aircraft comprising:
at least one unducted turbine engine for propulsion of the aircraft, the turbine engine extending along a longitudinal axis and being configured to accelerate an air flow circulating from upstream to downstream, the turbine engine comprising a rotor and a stator mounted downstream of the rotor, the stator comprising a plurality of stator vanes for straightening the air flow coming from the rotor extending radially with respect to the longitudinal axis and distributed angularly about the longitudinal axis, each of the stator vanes comprising a leading edge and a trailing edge defining between them a chord in a plane of revolution defined with respect to the longitudinal axis, each of the stator vanes being defined, in a plane transverse to the longitudinal axis, by an angular position, and
at least one aerodynamic obstacle, positioned close to the turbine engine, the aerodynamic obstacle causing a change in the circulation of the air flow downstream of the stator vanes,
wherein the plurality of stator vanes includes conventional vanes each defining a first cord and at least one elongated vane defining a second cord, and wherein the second chord is larger than the first chord, said at least one elongated vane being positioned in an interference angular range defined in relation with the aerodynamic obstacle, so as to increase the straightening of the air flow from the rotor in the interference angular range.

### Claim 2 (depends on 1)

The aircraft as claimed in claim 1, further comprising a connecting pylon for connecting the turbine engine to the aircraft, said pylon forming the aerodynamic obstacle.

### Claim 3 (depends on 1)

The aircraft according to claim 1, wherein the stator comprises at least two of the elongated vanes positioned within the interference angular range.

### Claim 4 (depends on 1)

The aircraft according to claim 1, wherein the angular positions of each the stator vanes are defined in a clockwise direction of rotation over an angular range of 0° to 360°, the angular position 0° being defined as a top position relative to a vertical axis, the aerodynamic obstacle extending substantially around an angular position (β), the assembly of the stator vanes positioned at the angular position of between −45° and +45° around the angular position (β) are the elongated vanes.

### Claim 5 (depends on 1)

The aircraft according to claim 1, wherein the plurality of stator vanes comprises at least one shortened vane that defines a third chord, the third chord being smaller than the first chord so as to limit a risk of underloading at least one of the stator vanes, said at least one shortened vane is positioned in an angular range diametrically opposed to the interference angular range.

### Claim 6 (depends on 5)

The aircraft as claimed in claim 5, wherein the at least one shortened vane is diametrically opposed to the at least one elongated vane.

### Claim 7 (depends on 5)

The aircraft according to claim 5, wherein the first chord defines a first length, and the third chord defines a third length, and wherein the third length is equal to 70% to 95% of the first length.

### Claim 8 (depends on 1)

The aircraft according to claim 1, wherein the first chord defines a first length and the second chord defines a second length, and wherein the second length is equal to between 105% and 130% of the first length.

### Claim 9 (depends on 1)

The aircraft according to claim 1, wherein a chord difference between two stator vanes that are adjacent to one another is less than or equal to 25%.

### Claim 10 (depends on 1)

The aircraft according to claim 1, wherein each of the stator vanes defines a maximum thickness in the plane of revolution, a relative thickness of the stator vane corresponding to a ratio of the maximum thickness to the chord, a difference in relative thickness between two of the stator vanes that are adjacent one another having different chords, is less than or equal to 25%.