# US 8,739,514 B2 · Low shock strength propulsion system

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- Number: US 8,739,514 B2
- Document ID: US8739514B2
- Status: Granted
- Kind: B2
- Application number: 12/257,982
- Filed: 2008-10-24
- Published: 2010-02-25
- Granted: 2014-06-03
- Earliest claimed: 2007-10-24
- Assignees: Gulfstream Aerospace Corporation
- Applicants: Timothy R. Conners
- Inventors: Timothy R. Conners
- Web page: https://patentgrep.com/patent/US8739514B2

## 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 is disclosed herein that employs a bypass flow path internal to the nacelle and around the engine. By shaping the nacelle, the nacelle may function to reduce sonic boom strength, cowl drag, and /or airframe interference drag. The nacelle may also function to improve total pressure recovery and/or total thrust of the primary flow path through the engine.

## Claims

### Claim 1

A supersonic nozzle for a supersonic engine, comprising:
an outer wall;
a bypass wall disposed within the outer wall, the bypass wall having a bypass wall leading edge positioned proximate an outer wall leading edge, the bypass wall being configured to continuously separate an aft directed airflow inside the outer wall into a primary flow portion and a bypass flow portion around the supersonic engine, the primary flow portion passing through the supersonic engine and the bypass flow portion passing through a bypass that bypasses the supersonic engine;
a set of struts configured to couple the outer wall with the bypass wall, the set of struts configured to tailor a direction of the bypass flow portion, and
an external compression inlet having an external compression surface upstream of the supersonic engine.

### Claim 2 (depends on 1)

The supersonic nozzle of claim 1, wherein the set of struts comprises composite or other lightweight material 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
wherein 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

A low shock supersonic nacelle, comprising:
an engine;
an external compression inlet having an external compression surface upstream of the engine;
an outer wall;
a bypass wall disposed within the outer wall, the bypass wall having a bypass wall leading edge positioned proximate an outer wall leading edge;
a set of struts configured to couple the outer wall with the bypass wall; an inlet module comprising front portions of the outer wall and the bypass wall, the inlet module configured to decelerate an incoming airflow to a speed compatible with the engine; and
a nozzle module comprising rear portions of the outer wall and the bypass wall, the nozzle module configured to accelerate an exhaust from the engine and a bypass;
wherein the bypass wall continuously divides the incoming aft directed airflow into a primary flow portion directed into the engine and a bypass flow portion directed into the bypass around the engine wherein the bypass flow portion bypasses the engine.

### Claim 11 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein the inlet module comprises:
a leading edge configured to generate a first shock wave;
a 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 compression surface such that the cowl lip and the compression surface define an inlet opening for receiving a supersonic flow;
wherein the compression surface is configured to generate a second shock wave that, during operation of the inlet module at a predetermined cruise speed, extends from the compression surface to intersect the first shock wave at a point substantially adjacent to the cowl lip.

### Claim 12 (depends on 11)

The low shock supersonic nacelle of claim 11, wherein the compression generated by the curved section is characterized by a series of Mach lines where, during operation of the inlet module 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 13 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein the bypass flow portion receives and captures a substantial region of flow distortion created by the inlet module.

### Claim 14 (depends on 10)

The low shock supersonic nacelle of claim 10, further comprising a diffuser that receives the primary flow portion and delivers a subsonic flow to the engine.

### Claim 15 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein the set of struts comprises composite materials configured to provide structural stiffness to the nozzle module.

### Claim 16 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein a thickness of the struts is configured to control an expansion of exhaust from the engine.

### Claim 17 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein the set of struts is constructed using linear surfaces within the nozzle module.

### Claim 18 (depends on 10)

The low shock supersonic nacelle of claim 10,
wherein the set of struts controls an amount of airflow depending on local blockage characteristics within the bypass; and
wherein the set of struts shapes the bypass flow portion around internal blockages created by a gearbox mounted on and about the engine.

### Claim 19 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein the set of struts directs the bypass flow portion into a substantially circumferentially uniform pattern prior to exhaust.

### Claim 20 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein the outer wall comprises a trailing edge that defines an exit cross-sectional area of the nozzle module.

### Claim 21 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein the nozzle module 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 22 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein the outer wall comprises a thin-wall composite construction.

### Claim 23 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein increasing a distance between the outer wall and the engine increases opportunities for localized, tailored, three-dimensional shaping of the outer wall.

### Claim 24 (depends on 10)

The low shock supersonic nacelle of claim 10, wherein the bypass attenuates instabilities in the incoming airflow at the inlet opening.

### Claim 25 (depends on 10)

The low shock supersonic nacelle of claim 10,
wherein the front portions of the outer wall and the bypass wall comprise aerodynamically coupled leading edges at a low flight speeds configured to generate an internal recirculating flow region immediately aft of the leading edge of the outer wall; and
wherein the internal recirculating flow region generates a smoothly curved virtual aerodynamic surface that reduces a downstream flow separation and distortion within the primary flow portion leading to the engine.

### Claim 26

A method of decelerating a supersonic flow for a supersonic propulsion system, the method comprising:
cruising at a predetermined supersonic speed;
receiving a supersonic flow in an external compression inlet having an external compression surface, a bypass splitter, and a cowl lip, the cowl lip spatially separated from and aft of the external compression surface;
splitting a subsonic flow into a primary flow portion and a bypass flow portion around an engine, whereby the bypass flow portion receives and captures a substantial region of a flow distortion created by the inlet;
diffusing the primary flow portion with a diffuser to a predetermined speed suitable for an engine;
expanding the primary flow portion after the primary flow portion leaves the engine and reaches a nozzle; and
directing the bypass flow portion into a substantially circumferentially uniform pattern prior to exhaust.

### Claim 27 (depends on 26)

The method of claim 26, further comprising:
generating a first shock wave from a leading edge of the external compression surface of the external compression inlet;
generating a second shock wave that, during operation of the external compression inlet a predetermined supersonic speed, extends from the external compression surface to intersect the first shock wave at a point substantially adjacent to the cowl lip; and generating compression of the supersonic flow by a curved section of the external compression surface.