# US 11,299,283 B2 · Aircraft having an aft engine

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- Number: US 11,299,283 B2
- Document ID: US11299283B2
- Status: Granted
- Kind: B2
- Application number: 16/512,730
- Filed: 2019-07-16
- Published: 2019-11-07
- Granted: 2022-04-12
- Earliest claimed: 2016-09-21
- Assignees: General Electric Company
- Applicants: General Electric Company
- Inventors: Kishore Ramakrishnan; Jixian Yao; Nikolai N. Pastouchenko; Ivan Malcevic
- Web page: https://patentgrep.com/patent/US11299283B2

## CPC

- B64D 27/14: within, or attached to, fuselages
- B64C 1/16: specially adapted for mounting power plant
- B64C 5/06: Fins (B64C5/08 takes precedence)
- B64C 21/01: Boundary layer ingestion [BLI] propulsion
- B64D 27/20: within, or attached to, fuselages
- B64C 2001/0045: {Fuselages characterised by special shapes}
- B64C 2230/04: by actively generating fluid flow
- Y02T 50/10: Drag reduction
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64C: AEROPLANES; HELICOPTERS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An aircraft is provided including a fuselage that extends along a longitudinal direction between a forward end and an aft end. A boundary layer ingestion fan is mounted to the fuselage at the aft end and is configured for ingesting boundary layer airflow off the surface of the fuselage. The fuselage defines a profile proximate the boundary layer ingestion fan that is optimized for ingesting a maximum amount of boundary layer air and improving propulsive efficiency of the aircraft. More specifically, the fuselage defines a cross sectional profile upstream of the boundary layer ingestion fan that has more cross sectional area in a top half relative to a bottom half as defined relative to a centerline of the boundary layer ingestion fan.

## Claims

### Claim 1

An aircraft defining a longitudinal direction, a vertical direction, and a lateral direction, the aircraft comprising:
a fuselage extending between a forward end and an aft end along the longitudinal direction, the fuselage defining a surface;
a boundary layer ingestion fan mounted to the fuselage at the aft end of the fuselage, the boundary layer ingestion fan defining a centerline and comprising a plurality of fan blades rotatable about the centerline and a nacelle surrounding the plurality of fan blades; and
a stabilizer attached to the fuselage and extending between a leading edge and a trailing edge,
wherein the surface of the fuselage defines:
a first point located in a plane perpendicular to the longitudinal direction and positioned where the leading edge of the stabilizer meets the fuselage;
a second point located in a plane perpendicular to the longitudinal direction and positioned where the trailing edge of the stabilizer meets the fuselage;
an inflection point;
a first portion of the surface, the first portion extending between the first point and the inflection point, the first portion being convex; and
a second portion of the surface, the second portion extending between the inflection point and the second point, the second portion being concave.

### Claim 2 (depends on 1)

The aircraft of claim 1, wherein the surface of the fuselage is a bottom surface of the fuselage.

### Claim 3 (depends on 1)

The aircraft of claim 1, wherein the surface of the fuselage is a top surface of the fuselage.

### Claim 4 (depends on 1)

The aircraft of claim 1, wherein the stabilizer is a vertical stabilizer.

### Claim 5 (depends on 1)

The aircraft of claim 1, wherein the inflection point is defined at a halfway point between the leading edge of the stabilizer and the trailing edge of the stabilizer.

### Claim 6 (depends on 1)

The aircraft of claim 1, wherein the inflection point is positioned upstream of an inlet of the boundary layer ingestion fan.

### Claim 7 (depends on 1)

The aircraft of claim 1, wherein the first portion defines a first radius of curvature and the second portion defines a second radius of curvature, the second radius of curvature being smaller than the first radius of curvature.

### Claim 8 (depends on 1)

The aircraft of claim 1, wherein the first portion defines a first radius of curvature and the second portion defines a second radius of curvature, the second radius of curvature being substantially the same as the first radius of curvature.

### Claim 9 (depends on 1)

The aircraft of claim 1, wherein a tangent line extends parallel to the surface of the fuselage and intersects a forward lip of the boundary layer ingestion fan, wherein the tangent line is parallel to the fuselage approximately halfway between the leading edge and the trailing edge of the stabilizer.

### Claim 10

An aircraft defining a longitudinal direction, a vertical direction, and a lateral direction, the aircraft comprising:
a fuselage extending between a forward end and an aft end along the longitudinal direction, the fuselage defining a surface;
a boundary layer ingestion fan mounted to the fuselage at the aft end of the fuselage, the boundary layer ingestion fan defining a centerline and comprising a plurality of fan blades rotatable about the centerline and a nacelle surrounding the plurality of fan blades; and
a stabilizer attached to the fuselage and extending along a junction line between a leading edge and a trailing edge,
wherein the surface of the fuselage defines:
a first region extending between the leading edge of the stabilizer and first point along the junction line, the first region having a first radius of curvature;
a second region extending between the first point and a second point along the junction line, the second region having a second radius of curvature; and
a third region extending between the second point and a third point along the junction line, the third region having a third radius of curvature.

### Claim 11 (depends on 10)

The aircraft of claim 10, wherein the first region and the second region are convex, and the third region is concave.

### Claim 12 (depends on 10)

The aircraft of claim 10, wherein the first region defines an average angle along a length of the first region relative to the longitudinal direction, the average angle being less than 10 degrees.

### Claim 13 (depends on 10)

The aircraft of claim 10, wherein the first radius of curvature is larger than the second radius of curvature.

### Claim 14 (depends on 10)

The aircraft of claim 10, wherein a ratio of the first radius of curvature to the second radius of curvature is greater than 2:1.

### Claim 15 (depends on 14)

The aircraft of claim 14, wherein the ratio is greater than 4:1.

### Claim 16 (depends on 10)

The aircraft of claim 10, wherein the second region defines an average angle along a length of the second region relative to the longitudinal direction, the average angle being less than 20 degrees.

### Claim 17 (depends on 10)

The aircraft of claim 10, wherein the third radius of curvature is substantially the same as the first radius of curvature.

### Claim 18 (depends on 10)

The aircraft of claim 10, wherein the third point is defined along the junction line at a location upstream of the plurality of fan blades of the boundary layer ingestion fan.

### Claim 19 (depends on 10)

The aircraft of claim 10, wherein the third point is at the trailing edge of the stabilizer.