# US 10,246,197 B2 · Aircraft

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- Number: US 10,246,197 B2
- Document ID: US10246197B2
- Status: Granted
- Kind: B2
- Application number: 15/280,170
- Filed: 2016-09-29
- Published: 2017-05-04
- Granted: 2019-04-02
- Earliest claimed: 2015-10-28
- Assignees: ROLLS-ROYCE plc
- Applicants: ROLLS-ROYCE plc
- Inventors: Rory D Stieger; Matthew Moxon; Mikko Mattila
- Web page: https://patentgrep.com/patent/US10246197B2

## CPC

- B64C 1/0009: {Aerodynamic aspects}
- B64C 21/01: Boundary layer ingestion [BLI] propulsion
- B64D 27/14: within, or attached to, fuselages
- B64D 33/02: of combustion air intakes
- B64C 2230/04: by actively generating fluid flow
- B64D 2033/0226: {comprising boundary layer control means}
- Y02T 50/10: Drag reduction
- B64C: AEROPLANES; HELICOPTERS
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An aircraft (10) comprising a fuselage (12), the fuselage (10) comprising at least first and second inwardly tapering portions (20, 22) extending in a generally rearward direction from an aft end of the fuselage (12), each inwardly tapering portion (20, 22) comprising a boundary layer ingesting propulsor (36) mounted thereon.

## Claims

### Claim 1

An aircraft having a central axis along a longitudinal direction of the aircraft, the aircraft comprising:
a fuselage including a main portion and a tail end portion, the tail end portion including a bifurcation that divides the fuselage along the central axis into at least a first inwardly tapering portion and a second inwardly tapering portion at an aft end of the fuselage, the first inwardly tapering portion and the second inwardly tapering portion each including at least one surface tapering inward towards the central axis relative to the main portion in both a width direction and a height direction of the aircraft, which are each orthogonal to the longitudinal direction; and
a boundary layer ingesting propulsor mounted on each of the first inwardly tapering portion and the second inwardly tapering portion of the tail end portion of the fuselage.

### Claim 2 (depends on 1)

The aircraft according to claim 1, wherein each of the first inwardly tapering portion and the second inwardly tapering portion extends from approximately a same longitudinal position.

### Claim 3 (depends on 1)

The aircraft according to claim 1, wherein the first inwardly tapering portion and the second inwardly tapering portion are arranged parallel to one another in a same horizontal plane.

### Claim 4 (depends on 1)

The aircraft according to claim 1, wherein the first inwardly tapering portion and the second inwardly tapering portion are arranged parallel to one another in a same vertical plane.

### Claim 5 (depends on 1)

The aircraft according to claim 1, wherein each propulsor is driven by a respective gas turbine engine.

### Claim 6 (depends on 1)

The aircraft according to claim 1, wherein at least two propulsors are driven by a common gas turbine engine core.

### Claim 7 (depends on 6)

The aircraft according to claim 6, wherein each propulsor is driven by a respective turbine driven by exhaust gases from a common gas generator.

### Claim 8 (depends on 5)

The aircraft according to claim 5, wherein each gas turbine engine includes a core flow inlet arranged to ingest one of a boundary layer air and a freestream air.

### Claim 9 (depends on 1)

The aircraft according to claim 1, further comprising:
a third inwardly tapering portion extending from the aft end of the fuselage, and
a boundary layer ingesting propulsor mounted on the third inwardly tapering portion, wherein:
each of the first inwardly extending tapering portion, the second inwardly tapering portion, and the third inwardly tapering portion extend from a same longitudinal position.

### Claim 10 (depends on 1)

The aircraft according to claim 1, wherein each of the first inwardly tapering portion and the second inwardly tapering portion includes a non-axisymmetric portion upstream of an inlet of the respective propulsor, the non-axisymmetric portion defining a twist in an opposite sense to a rotational direction of a propulsor fan or a propeller.

### Claim 11 (depends on 1)

The aircraft according to claim 1, wherein the fuselage includes at least one guide vane located upstream of at least one propulsor inlet.