Connecting a propulsion system to a structural element of an aircraft

1. An aircraft propulsion system comprising:

a bypass turbojet engine surrounded by a nacelle defining a passage in which a secondary stream flows, and

a connection device that connects the engine under a structural element of an aircraft, the connection device comprising a pylon situated radially outside the flow passage for the secondary stream and lying in a plane substantially parallel to a longitudinal axis of the engine, and

a suspension device that suspends the engine from the pylon, the plane of the pylon being angularly offset from a vertical plane containing the longitudinal axis of the engine, wherein

the suspension device that suspends the engine from the pylon comprises two parallel and substantially horizontal transverse beams that connect the pylon to hinges on top portions of casings of the engine, and wherein

the pylon further comprises an additional arm supporting an engine thrust take-up device, the additional arm extending from the pylon towards the engine and being connected at its free end to a crossbar having ends connected to an intermediate casing via links.

2. A propulsion system according to claim 1 , wherein the pylon is offset about the longitudinal axis of the engine by an angle lying in the range 30° to 60°, approximately, away from the vertical plane and from the top of the nacelle.

3. A propulsion system according to claim 1 , wherein the pylon carries an upstream transverse beam that is connected by a first hinge to a top portion of the intermediate casing of the engine, and a downstream transverse beam that is connected by a second hinge to a top portion of an exhaust casing of the engine.

4. A propulsion system according to claim 3 , wherein the first hinge of the upstream transverse beam connected to the top portion of the intermediate casing comprise three links, a first link connected to the free end of the beam, a second link connected to an intermediate portion of the beam, and a third link connected to the beam between its intermediate portion and the pylon.

5. A propulsion system according to claim 3 , wherein the downstream transverse beam is connected at its free end to two links in a V-shaped configuration that are hinged to the top portion of the exhaust casing.

6. A propulsion system according to claim 5 , wherein the two links in the V-shaped configuration pass through the passage for passing the secondary stream and are faired, at least in part.

7. A propulsion system according to claim 4 , wherein at least some of the three links are hinged to the upstream transverse beam and to the intermediate casing via ball-and-socket connections.

8. A propulsion system according to claim 1 , wherein the additional arm is an oblique rigid arm.

9. A propulsion system according to claim 8 , wherein the oblique rigid arm extends substantially radially relative to the longitudinal axis of the engine.

10. A propulsion system according to claim 8 , wherein connection points between the links and the intermediate casing are spaced apart from each other about the longitudinal axis of the engine by an angle lying in the range 90° to 180°, approximately.

11. A propulsion system according to claim 10 , wherein the connection points of the links are symmetrical to each other relative to an oblique plane containing the longitudinal axis of the engine and the pylon.

12. A propulsion system according to claim 8 , wherein the oblique rigid arm forms a portion of a streamlined duct for passing services such as fluid-conveying pipes and electric cables.

13. A propulsion system according to claim 1 , wherein the ends of the crossbar are connected to the intermediate casing via two links.

14. An aircraft propulsion system comprising:

a bypass turbojet engine surrounded by a nacelle defining a passage in which a secondary stream flows, and

connection means for connecting the engine under a structural element of an aircraft, the connection means comprising a pylon situated radially outside the flow passage for the secondary stream and lying in a plane substantially parallel to a longitudinal axis of the engine, and

means for suspending the engine from the pylon, the plane of the pylon being angularly offset from a vertical plane containing the longitudinal axis of the engine, wherein

the means for suspending the engine from the pylon comprise two parallel and substantially horizontal transverse beams that connect the pylon to hinge means on top portions of casings of the engine, and wherein

the pylon comprises an oblique rigid arm supporting engine thrust take-up means, the arm extending from the pylon towards the engine and being connected at its free end to a crossbar having ends connected to the intermediate casing via links.

15. A propulsion system according to claim 14 , wherein the ends of the crossbar are connected to the intermediate casing via two links.