# US 8,783,039 B2 · Low shock strength propulsion system

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- Number: US 8,783,039 B2
- Document ID: US8783039B2
- Status: Granted
- Kind: B2
- Application number: 12/605,071
- Filed: 2009-10-23
- Published: 2013-03-14
- Granted: 2014-07-22
- Earliest claimed: 2007-10-24
- Assignees: Gulfstream Aerospace Corporation
- Applicants: Timothy R. Conners
- Inventors: Timothy R. Conners
- Web page: https://patentgrep.com/patent/US8783039B2

## CPC

- B64D 33/02: of combustion air intakes
- B64D 29/00: Power-plant nacelles, fairings or cowlings
- B64D 33/06: {Silencing exhaust or propulsion jets}
- F02C 7/042: having variable geometry
- F02C 7/045: having provisions for noise suppression
- F02K 3/025: {the by-pass flow being at least partly used to create an independent thrust component}
- F02K 7/16: Composite ram-jet/turbo-jet engines
- B64D 2033/026: {for supersonic or hypersonic aircraft}
- B64D 2033/0273: {for jet engines}
- F05D 2220/80: in supersonic vehicles excluding hypersonic vehicles or ram, scram or rocket propulsion
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- Y10T 137/0368: By speed of fluid
- Y10T 137/0536: Highspeed fluid intake means [e.g., jet engine intake]
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- 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
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A supersonic nacelle design employing a bypass flow path internal to the nacelle and around the engine is disclosed herein. A set of aerodynamic vanes may be used to shape a supersonic airflow within a bypass around an engine. The vanes may be capable of directing the subsonic airflow around the engine, and then expanding the subsonic airflow into a supersonic exhaust. The vanes may shape the airflow by reducing sonic boom strength, cowl drag, and airframe interference drag.

## Claims

### Claim 1

A supersonic nozzle for a supersonic engine, comprising:
an outer wall;
a bypass wall disposed within the outer wall and configured to separate an airflow inside the outer wall into a primary flow portion and a bypass flow portion, the primary flow portion passing through a supersonic engine and the bypass flow portion passing through a bypass that bypasses the supersonic engine, the bypass flow portion comprising a subsonic flow;
a set of struts configured to couple the outer wall with the bypass wall, the set of struts tailoring a direction of the bypass flow portion, the set of struts further configured to direct the bypass flow portion around the supersonic engine and to expand the bypass flow portion into a supersonic exhaust, a first sub-set of the set of struts having a first curvature that directs the bypass flow portion in a first circumferential direction around a protruding portion of the supersonic engine, a second sub-set of the set of struts having a second curvature that directs the bypass flow portion in a second circumferential direction around a protruding portion of the supersonic engine, a third sub-set of the set of struts disposed downstream of the first sub-set and having a third curvature that directs the bypass flow portion in the second circumferential direction, and a fourth sub-set of the set of struts disposed downstream of the second sub-set and having a fourth curvature that directs the bypass flow portion in the first circumferential direction; and
an external compression inlet having an external compression surface upstream of the supersonic engine and the bypass.

### Claim 2 (depends on 1)

The supersonic nozzle of claim 1, wherein the set of struts comprises composite materials for providing structural stiffness to the supersonic nozzle.

### Claim 3 (depends on 1)

The supersonic nozzle of claim 1, wherein a thickness of the struts is configured to control an expansion of an exhaust from the supersonic engine.

### Claim 4 (depends on 1)

The supersonic nozzle of claim 1, wherein the set of struts is constructed using linear surfaces.

### Claim 5 (depends on 1)

The supersonic nozzle of claim 1, wherein the set of struts controls an amount of airflow depending on local blockage characteristics within the bypass flow portion; and
the set of struts shapes the bypass flow portion around internal blockages created by a gearbox of the supersonic engine.

### Claim 6 (depends on 1)

The supersonic nozzle of claim 1, wherein the set of struts directs the bypass flow portion into a substantially circumferentially uniform pattern prior to exhaust.

### Claim 7 (depends on 1)

The supersonic nozzle of claim 1, wherein the outer wall comprises a trailing edge that defines an exit cross-sectional area of the supersonic nozzle.

### Claim 8 (depends on 1)

The supersonic nozzle of claim 1, wherein the supersonic nozzle expands the bypass flow portion to maximize a thrust of the supersonic engine and to minimize a sonic boom signature generated by exhaust of the primary flow portion.

### Claim 9 (depends on 1)

The supersonic nozzle of claim 1, wherein the outer wall comprises a thin-wall composite construction.

### Claim 10 (depends on 1)

The supersonic nozzle of claim 1, wherein the set of struts receive the bypass flow portion and direct the bypass flow portion into a subsonic flow portion.

### Claim 11

A low shock supersonic nacelle, comprising:
an engine;
an outer wall;
a bypass wall disposed within the outer wall and configured to support the engine;
a set of struts configured to couple the outer wall with the bypass wall, a first sub-set of the set of struts having a first curvature that directs the bypass flow portion in a first circumferential direction around a protruding portion of the supersonic engine, a second sub-set of the set of struts having a second curvature that directs the bypass flow portion in a second circumferential direction around a protruding portion of the supersonic engine, a third sub-set of the set of struts disposed downstream of the first sub-set and having a third curvature that directs the bypass flow portion in the second circumferential direction, and a fourth sub-set of the set of struts disposed downstream of the second sub-set and having a fourth curvature that directs the bypass flow portion in the first circumferential direction;
an inlet defined by front portions of the outer wall and the bypass wall, the inlet configured to decelerate an incoming airflow to a speed compatible with the engine; and
a nozzle defined by rear portions of the outer wall and the bypass wall, the nozzle configured to accelerate an exhaust from the engine and bypass, wherein the bypass wall divides the incoming airflow into a primary flow portion directed into the engine and a bypass flow portion directed into a bypass that bypasses the engine, the bypass flow portion comprising a subsonic flow,
wherein the inlet comprises an external compression inlet having an external compression surface upstream of the engine and the bypass, and
wherein the set of struts is further configured to direct the bypass flow portion around the engine and to expand the bypass flow portion into a supersonic exhaust.

### Claim 12 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the inlet comprises:
a leading edge configured to generate a first shock wave;
the external compression surface positioned downstream of the leading edge and having at least one curved section configured to generate compression; and
a cowl lip on a cowling spatially separated from the external compression surface such that the cowl lip and the external compression surface define an inlet opening for receiving a supersonic flow;
wherein the external compression surface is configured to generate a second shock wave that, during operation of the inlet at a predetermined cruise speed, extends from the external compression surface to intersect the first shock wave at a point substantially adjacent to the cowl lip.

### Claim 13 (depends on 12)

The low shock supersonic nacelle of claim 12, wherein the compression generated by the curved section is characterized by a series of Mach lines where, during operation of the inlet at the predetermined cruise speed, at least a plurality of the Mach lines do not focus on the point substantially adjacent to the cowl lip.

### Claim 14 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the bypass flow portion receives a diffused region of flow distortion.

### Claim 15 (depends on 11)

The low shock supersonic nacelle of claim 11, further comprising a diffuser that receives the primary flow portion and delivers a subsonic flow to the engine.

### Claim 16 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the set of struts comprises composite materials configured to provide structural stiffness to the nozzle.

### Claim 17 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein a thickness of the struts is configured to control an expansion of exhaust from the engine.

### Claim 18 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the set of struts is constructed using linear surfaces.

### Claim 19 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the set of struts controls an amount of airflow depending on local blockage characteristics within the bypass; and
the set of struts shapes the bypass flow portion around internal blockages created by a gearbox of the engine.

### Claim 20 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the set of struts directs the bypass flow portion into a substantially circumferentially uniform pattern prior to exhaust.

### Claim 21 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the outer wall comprises a trailing edge that defines an exit cross-sectional area of the nozzle.

### Claim 22 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the nozzle expands the bypass flow portion to maximize a thrust of the supersonic engine and to minimize a sonic boom signature created by the primary flow portion.

### Claim 23 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the outer wall comprises a thin-wall composite construction.

### Claim 24 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein increasing a distance between the outer wall and the engine increases opportunities for localized, tailored, three-dimensional shaping of the outer wall.

### Claim 25 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the bypass attenuates instabilities in the incoming airflow at the inlet.

### Claim 26 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the set of struts receive the bypass flow portion and direct the bypass flow portion into a subsonic flow portion.

### Claim 27

A nacelle for a supersonic engine, comprising:
an outer wall defining a closed volume;
a bypass wall disposed within the closed volume of the outer wall, the outer wall and the bypass wall cooperating to form a bypass that bypasses the supersonic engine;
a set of vanes configured to couple the outer wall with the bypass wall, defining a bypass therebetween, the set of vanes directing a bypass airflow into a subsonic flow, the set of vanes further configured to direct the subsonic flow around the supersonic engine and to expand the subsonic flow into a supersonic exhaust, a first sub-set of the set of vanes having a first curvature that directs the bypass flow portion in a first circumferential direction around a protruding portion of the supersonic engine, a second sub-set of the set of vanes having a second curvature that directs the bypass flow portion in a second circumferential direction around a protruding portion of the supersonic engine, a third sub-set of the set of vanes disposed downstream of the first sub-set and having a third curvature that directs the bypass flow portion in the second circumferential direction, and a fourth sub-set of the set of vanes disposed downstream of the second sub-set and having a fourth curvature that directs the bypass flow portion in the first circumferential direction; and
an external compression inlet having an external compression surface upstream of the supersonic engine and the bypass.

### Claim 28 (depends on 27)

The nacelle of claim 27, wherein the set of vanes expands the subsonic flow into a substantially circumferentially uniform pattern prior to exhaust.

### Claim 29 (depends on 27)

The nacelle of claim 27, wherein the set of vanes controls an amount of airflow depending on local blockage characteristics within the subsonic flow; and
the set of vanes shapes the subsonic flow around internal blockages created by the gearbox of the supersonic engine.

### Claim 30 (depends on 27)

The nacelle of claim 27, wherein the bypass wall is configured to separate an airflow inside the outer wall into a primary airflow and the bypass airflow, the primary airflow passing through a supersonic engine.

### Claim 31

A low shock supersonic nacelle, comprising:
an engine;
an outer wall defining a closed volume;
a bypass wall disposed within the closed volume of the outer wall and configured to support the engine;
a set of vanes configured to couple the outer wall with the bypass wall, a first sub-set of the set of vanes having a first curvature that directs the bypass flow portion in a first circumferential direction around a protruding portion of the supersonic engine, a second sub-set of the set of vanes having a second curvature that directs the bypass flow portion in a second circumferential direction around a protruding portion of the supersonic engine, a third sub-set of the set of vanes disposed downstream of the first sub-set and having a third curvature that directs the bypass flow portion in the second circumferential direction, and a fourth sub-set of the set of vanes disposed downstream of the second sub-set and having a fourth curvature that directs the bypass flow portion in the first circumferential direction;
an inlet defined by front portions of the outer wall and the bypass wall, the inlet configured to decelerate an incoming airflow to a speed compatible with the engine, the bypass wall dividing the incoming airflow into a primary flow portion directed into the engine and a bypass flow portion directed into a bypass that bypasses the engine, the bypass flow portion comprising a subsonic flow; and
a nozzle defined by rear portions of the outer wall and the bypass wall, the nozzle configured to accelerate an exhaust from the engine and the bypass,
wherein the inlet comprises an external compression inlet having an external compression surface upstream of the engine and the bypass,
wherein the set of vanes is further configured to direct the bypass flow portion around the engine and to expand the bypass flow portion into a supersonic exhaust.

### Claim 32 (depends on 30)

The low shock supersonic nacelle of claim 30, wherein the inlet comprises:
a leading edge configured to generate a first shock wave;
the external compression surface positioned downstream of the leading edge and having at least one curved section configured to generate compression; and
a cowl lip on a cowling spatially separated from the external compression surface such that the cowl lip and the external compression surface define an inlet opening for receiving a supersonic flow;
wherein the external compression surface is configured to generate a second shock wave that, during operation of the inlet at a predetermined cruise speed, extends from the external compression surface to intersect the first shock wave at a point substantially adjacent to the cowl lip.

### Claim 33 (depends on 30)

The low shock supersonic nacelle of claim 30, further comprising:
an inlet compression surface generating a terminal shock formed close to a leading edge of the outer wall.

### Claim 34 (depends on 30)

The low shock supersonic nacelle of claim 30, wherein the nozzle expands the bypass flow portion to maximize a thrust of the supersonic engine and to minimize a sonic boom signature created by the primary flow portion.

### Claim 35 (depends on 30)

The low shock supersonic nacelle of claim 30, wherein the bypass attenuates instabilities in the incoming airflow at the inlet.