# US 5,343,695 A · Combined jet engine provided with means for switching between two operating states

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- Number: US 5,343,695 A
- Document ID: US5343695A
- Status: Granted
- Kind: A
- Application number: 08/075,879
- Filed: 1993-06-14
- Granted: 1994-09-06
- Earliest claimed: 1992-06-24
- Assignees: Societe Nationale d'Etude et de Construction de Moteurs d'Aviation "S.N.E.C.M.A."
- Inventors: Noel B. Pascal; Georges Mazeaud; Claude W. Pascal
- Web page: https://patentgrep.com/patent/US5343695A

## CPC

- F02K 7/16: Composite ram-jet/turbo-jet engines
- F02C 7/042: having variable geometry
- 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)
- 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)

## Abstract

A jet engine has a central turbojet stream and a peripheral ram jet stream which can be in turn obstructed or freed by flaps. The flaps can be opened outwardly and are located on an intake cone and at an inlet of the peripheral stream. The operation of the flaps is a function of the sought operating mode. This arrangement permits a very good guidance of gases.

## Claims

### Claim 1

A jet engine having a gas circulation stream subdivided over part of its length into a central stream and a peripheral stream, the jet engine incorporating internal flaps which are mobile about internal articulated joints located at a center of an inlet of the central stream and external flaps which are mobile about external articulated joints located in an area between the central stream and the peripheral stream, the internal flaps having a substantially axial orientation in a first operating mode where the central stream is open and a conical orientation in a second operating mode where the central stream is obstructed, wherein the external flaps are positioned in front of an inlet of the peripheral stream and are mobile in such a way that the external flaps obstruct the inlet of the peripheral stream during the first operating mode and assume a conical orientation during the second operating mode by meeting at an end opposite to the external articulated joints with an end of the internal flaps opposite to the internal articulated joints, the internal and external flaps then forming a substantially conical common surface, which deflects gases towards the peripheral stream and obstructs the central stream.

### Claim 2 (depends on 1)

A jet engine according to claim 1, wherein the internal flaps are constituted by articulated concentric layers between the internal articulated joints and an actuating means, abutment devices between the layers being provided in order to limit their angular movements.

### Claim 3 (depends on 2)

A jet engine according to claim 2, wherein the abutment devices are constituted by rods provided with clearance links between consecutive articulated parts.