Patent Description:
An exhaust nozzle for an aircraft propulsion system may include an ejector for introducing supplemental air (e.g., ambient air from outside of the aircraft propulsion system) into a low pressure region of the exhaust nozzle. Various types and configurations of exhaust nozzles with ejectors are known in the art. While these known exhaust nozzles have various advantages, there is still room in the art for improvement. There is a need in the art therefore for an improved exhaust nozzle with an ejector.

A prior art apparatus for an aircraft propulsion system, having the features of the preamble of claim <NUM>, is disclosed in <CIT>. Another prior art apparatus for an aircraft propulsion system is disclosed in <CIT>.

According to an aspect of the present invention, an apparatus is provided for an aircraft propulsion system, as claimed in claim <NUM>.

The exhaust nozzle may be configured as or otherwise include a convergent-divergent nozzle.

The exhaust nozzle may be configured as or otherwise include an ejector nozzle.

The actuator may be configured as or otherwise include a linear actuator.

The exhaust nozzle may also include a linkage system motively coupling the actuator to the outer door and the inner door.

The linkage system may include a pushrod.

The exhaust nozzle may also include a base structure, an outer crank and an outer linkage. The outer crank may include an outer crank base, an outer crank first arm and an outer crank second arm. The outer crank base may be pivotally connected to the base structure. The outer crank first arm and the outer crank second arm may each project out from the outer crank base. The outer linkage may be between and/or pivotally connected to the outer crank first arm and the outer door. The actuator may be motively coupled with the outer crank second arm.

The exhaust nozzle may also include a base structure and an inner crank. The inner crank may include an inner crank base, an inner crank first arm and an inner crank second arm. The inner crank base may be pivotally connected to the base structure. The inner crank first arm may project out from the base and/or may be pivotally connected to the inner door. The inner crank second arm may project out from the base and/or may be pivotally connected to the actuator.

The exhaust nozzle may also include an outer crank, an outer linkage and an intermediate linkage. The outer crank may include an outer crank base, an outer crank first arm and an outer crank second arm. The outer crank base may be pivotally connected to the base structure. The outer crank first arm and the outer crank second arm may each project out from the outer crank base. The outer linkage may be between and/or pivotally connected to the outer crank first arm and the outer door. The intermediate linkage may be between and/or pivotally connected to the outer crank second arm and the inner crank second arm.

The outer door may be configured to pivot between the closed arrangement and the open arrangement about an outer door pivot connection at a forward end of the outer door.

The inner door may be configured to pivot between the closed arrangement and the open arrangement about an inner door pivot connection at an aft end of the inner door.

The inner door may include a forward inner door. The exhaust nozzle may also include an aft inner door pivotally connected to the forward inner door. The actuator may also be configured to move the aft inner door between the open arrangement and the closed arrangement. The aft inner door may be configured to pivot outwards away from the centerline when the aft inner door moves from the closed arrangement to the open arrangement.

The outer door may form an inner peripheral boundary for flow outside of the exhaust nozzle when the outer door is in the closed arrangement. In addition or alternatively, the forward inner door and the aft inner door may form an outer peripheral boundary of the flowpath when the forward inner door and the aft inner door are in the closed arrangement.

The present disclosure may include any one or more of the individual features disclosed above and/or below alone or in any combination thereof, insofar as they fall within the scope of the claims.

<FIG> illustrates an aircraft propulsion system <NUM> for an aircraft; e.g., a jet plane. This aircraft propulsion system <NUM> includes a gas turbine engine <NUM> and an aircraft propulsion system housing <NUM>.

The gas turbine engine <NUM> may be configured as a turbojet engine, or any other type of gas turbine engine such as a turbofan engine. The gas turbine engine <NUM> of <FIG>, for example, includes a compressor section <NUM>, a combustor section <NUM> and a turbine section <NUM>. The compressor section <NUM> may include a low pressure compressor (LPC) section 26A and a high pressure compressor (HPC) section 26B. The combustor section <NUM> includes a combustor <NUM>. The turbine section <NUM> may include a high pressure turbine (HPT) section 28A and a low pressure turbine (LPT) section 28B.

The engine sections 26A-28B are arranged sequentially along an axial centerline <NUM> (e.g., a rotational axis) of the gas turbine engine <NUM> within the aircraft propulsion system housing <NUM>. This aircraft propulsion system housing <NUM> includes an engine case <NUM> and a nacelle <NUM>. The engine case <NUM> houses one or more of the engine sections 26A-28B, which engine sections 26A-28B may be collectively referred to as an engine core. The nacelle <NUM> houses and provides an aerodynamic cover for the engine case <NUM>. The aircraft propulsion system housing <NUM> of <FIG> also forms an upstream, forward airflow inlet structure <NUM> and a downstream, aft exhaust nozzle <NUM> for the aircraft propulsion system <NUM>.

Each of the engine sections 26A, 26B, 28A and 28B includes a bladed rotor <NUM>-<NUM>. Each of these bladed rotors <NUM>-<NUM> includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. The rotor blades, for example, may be formed integral with or mechanically fastened, welded, brazed, adhered and/or otherwise attached to the respective rotor disk(s).

The LPC rotor <NUM> is connected to and driven by the LPT rotor <NUM> through a low speed shaft <NUM>. The HPC rotor <NUM> is connected to and driven by the HPT rotor <NUM> through a high speed shaft <NUM>. The shafts <NUM> and <NUM> are rotatably supported by a plurality of bearings (not shown). Each of these bearings is connected to the aircraft propulsion system housing <NUM> and its engine case <NUM> by at least one stationary structure such as, for example, an annular support frame.

During operation, air enters the aircraft propulsion system <NUM> through the inlet structure <NUM> and is directed into a core flowpath <NUM>. The core flowpath <NUM> extends axially along the axial centerline <NUM> within the aircraft propulsion system <NUM>. More particularly, the core flowpath <NUM> extends axially through the engine sections 26A-28B and the exhaust nozzle <NUM> to an aft outlet orifice <NUM> of the exhaust nozzle <NUM>. The air within the core flowpath <NUM> may be referred to as "core air".

The core air is compressed by the LPC rotor <NUM> and the HPC rotor <NUM>, and directed into a combustion chamber of the combustor <NUM>. Fuel is injected into the combustion chamber and mixed with the compressed core air to provide a fuel-air mixture. This fuel-air mixture is ignited and combustion products thereof flow through and sequentially cause the HPT rotor <NUM> and the LPT rotor <NUM> to rotate. The rotation of the HPT rotor <NUM> and the LPT rotor <NUM> respectively drive rotation of the HPC rotor <NUM> and the LPC rotor <NUM> and, thus, compression of the air received through the inlet structure <NUM>. The aircraft propulsion system <NUM> of the present disclosure, however, is not limited to the exemplary gas turbine engine configuration described above.

Under certain operating conditions, it may be beneficial to provide variability at the exhaust nozzle <NUM> to enhance aircraft propulsion system operation. To provide such variability, the exhaust nozzle <NUM> may be configured as a convergent-divergent ejector nozzle. The exhaust nozzle <NUM> of <FIG>, for example, is configured to selectively direct supplemental air (e.g., ambient air from outside of the aircraft propulsion system <NUM>) into a low pressure region of the core flowpath <NUM> within the exhaust nozzle <NUM>. Introduction of this supplemental air may energize a relatively slow, outer stream of the combustion products flowing through the core flowpath <NUM> and thereby enhance overall engine thrust.

The exhaust nozzle <NUM> of <FIG> and <FIG> is configured with a central exhaust flowpath <NUM> and one or more outer ejector passages <NUM> (see <FIG>), where the exhaust flowpath <NUM> may be an aft, downstream section of the core flowpath <NUM> within the exhaust nozzle <NUM>. The exhaust nozzle <NUM> of <FIG> and <FIG> includes a nozzle base structure <NUM>, one or more nozzle outer doors <NUM>, one or more nozzle upstream, forward inner doors <NUM> and one or more nozzle downstream, aft inner doors <NUM>. This exhaust nozzle <NUM> also includes a nozzle actuator system <NUM> for moving the nozzle doors <NUM>-<NUM>.

Referring to <FIG>, the base structure <NUM> extends axially along the axial centerline <NUM> from an upstream, forward end <NUM> of the exhaust nozzle <NUM> to a downstream, aft end <NUM> of the exhaust nozzle <NUM>; e.g., a trailing edge of the exhaust nozzle <NUM>. The base structure <NUM> of <FIG> has a polygonal (e.g., rectangular) tubular body with a nozzle sidewall structure <NUM> that extends (e.g., circumferentially) about the axial centerline <NUM>. Referring to <FIG> and <FIG>, the base structure <NUM> and its sidewall structure <NUM> extend laterally (e.g., in a radial direction in <FIG> and <FIG>) between and to a lateral inner side <NUM> of the exhaust nozzle <NUM> and a lateral outer side <NUM> of the exhaust nozzle <NUM>, where the nozzle inner side <NUM> forms an outer peripheral boundary of the exhaust flowpath <NUM> through the exhaust nozzle <NUM> to the nozzle outlet orifice <NUM>, and where the nozzle outer side <NUM> forms an inner peripheral boundary for flow (e.g., ambient boundary layer air) outside of the exhaust nozzle <NUM>.

The base structure <NUM> of <FIG> and <FIG> includes a fixed structure <NUM> and one or more restrictors <NUM>; e.g., divergent nozzle flaps. An upstream, forward section <NUM> of the fixed structure <NUM> forms an upstream, forward portion of the nozzle inner side <NUM> and an upstream, forward portion of the nozzle outer side <NUM>. A downstream, aft section <NUM> of the fixed structure <NUM> forms a downstream, aft portion of the nozzle outer side <NUM> which extends to the nozzle aft end <NUM>. The restrictors <NUM> are arranged on opposing (e.g., upper and lower) sides of the axial centerline <NUM> and respectively form intermediate portions of the nozzle inner side <NUM>. Each of the restrictors <NUM> is movably coupled with the fixed structure <NUM>. Each of the restrictors <NUM> of <FIG> and <FIG>, for example, is pivotally connected to the structure forward section <NUM>. These restrictors <NUM> are configured to pivot inward towards and outward away from the axial centerline <NUM> in order to tune the flow of combustion products directed through the exhaust nozzle <NUM>. However, these restrictors <NUM> are typically stationary (not moved) during operation of the ejector functionality of the exhaust nozzle <NUM>.

Each of the ejector passages <NUM> extend laterally and/or axially (e.g., diagonally) into the exhaust nozzle <NUM> to the exhaust flowpath <NUM>. Each ejector passage <NUM> of <FIG>, for example, extends through the sidewall structure <NUM> of the exhaust nozzle <NUM> between and to an outer inlet orifice <NUM> to the respective ejector passage <NUM> and an inner outlet orifice <NUM> from the respective ejector passage <NUM>. The passage inlet orifice <NUM> is located at the nozzle outer side <NUM>. The passage outlet orifice <NUM> is located at the nozzle inner side <NUM> along the exhaust flowpath <NUM>. Each ejector passage <NUM> extends within the sidewall structure <NUM> axially along the axial centerline <NUM> between and to an upstream, forward side <NUM> (relative to flow through the exhaust flowpath <NUM>) of the respective ejector passage <NUM> and a downstream, aft side <NUM> (relative to flow through the exhaust flowpath <NUM>) of the respective ejector passage <NUM>. The passage forward side <NUM> of <FIG> is formed by the structure forward section <NUM> and a respective one of the restrictors <NUM> as well as the outer doors <NUM>. The passage aft side <NUM> of <FIG> is formed by the structure aft section <NUM> and a respective one of the nozzle forward inner doors <NUM>.

The nozzle outer doors <NUM> of <FIG> and <FIG> are arranged on opposing (e.g., upper and lower, left and right hand sides if turned <NUM>°, etc.) sides of the axial centerline <NUM>. Each nozzle outer door <NUM> extends longitudinally between an upstream, forward end <NUM> of the respective nozzle outer door <NUM> and a downstream, aft end <NUM> of the respective nozzle outer door <NUM>. Each nozzle outer door <NUM> is moveably coupled with the base structure <NUM>. Each nozzle outer door <NUM> of <FIG> and <FIG>, for example, is pivotally connected to the fixed structure <NUM> and its structure forward section <NUM> through a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) at the outer door forward end <NUM>. Each nozzle outer door <NUM> may thereby pivot laterally inward towards the axial centerline <NUM> from an outer door closed position (see <FIG>) to an outer door open position (see <FIG>), and vice versa. Referring to <FIG>, each nozzle outer door <NUM> is in its closed position when the exhaust nozzle <NUM> is in a first arrangement / a first mode of operation; e.g., when the ejector functionality is not in use. Referring to <FIG>, each nozzle outer door <NUM> is in its open position when the exhaust nozzle <NUM> is in a second arrangement / a second mode of operation; e.g., when the ejector functionality is in use.

The nozzle forward inner doors <NUM> of <FIG> and <FIG> are arranged on opposing (e.g., upper and lower) sides of the axial centerline <NUM>. Each nozzle forward inner door <NUM> extends longitudinally between an upstream, forward end <NUM> of the respective nozzle forward inner door <NUM> and a downstream, aft end <NUM> of the respective nozzle forward inner door <NUM>. Each nozzle forward inner door <NUM> is movably coupled with a respective one of the nozzle aft inner doors <NUM>. Each nozzle forward inner door <NUM> of <FIG> and <FIG>, for example, is pivotally connected to the respective nozzle aft inner door <NUM> through a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) at the forward inner door aft end <NUM> and an upstream, forward end <NUM> of the respective nozzle aft inner door <NUM>. Each nozzle forward inner door <NUM> may thereby pivot laterally outwards away from the axial centerline <NUM> from a forward inner door closed position (see <FIG>) to a forward inner door open position (see <FIG>), and vice versa. Referring to <FIG>, each nozzle forward inner door <NUM> is in its closed position when the exhaust nozzle <NUM> is in the first arrangement / the first mode of operation. Referring to <FIG>, each nozzle forward inner door <NUM> is in its open position when the exhaust nozzle <NUM> is in the second arrangement / the second mode of operation.

The nozzle aft inner doors <NUM> of <FIG> and <FIG> are arranged on opposing (e.g., upper and lower) sides of the axial centerline <NUM>. Each nozzle aft inner door <NUM> extends longitudinally between its aft inner door forward end <NUM> and a downstream, aft end <NUM> of the respective nozzle aft inner door <NUM>. Each nozzle aft inner door <NUM> is movably coupled with the base structure <NUM>. Each nozzle aft inner door <NUM> of <FIG> and <FIG>, for example, is pivotally connected to the fixed structure <NUM> and its structure aft section <NUM> through a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) at the aft inner door aft end <NUM> and at the nozzle aft end <NUM>. Each nozzle aft inner door <NUM> may thereby pivot laterally outwards away from the axial centerline <NUM> from an aft inner door closed position (see <FIG>) to an aft inner door open position (see <FIG>), and vice versa. Referring to <FIG>, each nozzle aft inner door <NUM> is in its closed position when the exhaust nozzle <NUM> is in the first arrangement / the first mode of operation. Referring to <FIG>, each nozzle aft inner door <NUM> is in its open position when the exhaust nozzle <NUM> is in the second arrangement / the second mode of operation. A size (e.g., a minimum lateral height) of the exhaust flowpath <NUM> within the exhaust nozzle <NUM> along the nozzle aft inner doors <NUM> is thereby greater in in the second arrangement / the second mode of operation (see <FIG>) than in the first arrangement / the first mode of operation (see <FIG>).

The nozzle actuator system <NUM> of <FIG> and <FIG> includes a plurality of actuator assemblies <NUM>. The actuator assemblies <NUM> are arranged on opposing (e.g., upper and lower) sides of the axial centerline <NUM>, where each actuator assembly <NUM> is associated with a respective one of the nozzle outer doors <NUM>, a respective one of the nozzle forward inner doors <NUM> and a respective one of the nozzle aft inner doors <NUM>. Referring to <FIG>, each actuator assembly <NUM> includes a linkage system <NUM> and one or more actuators <NUM>. The linkage system <NUM> of <FIG> includes one or more outer cranks <NUM>, one or more outer linkages <NUM>, one or more intermediate (e.g., tie) linkages <NUM> and at least one inner crank <NUM>.

The outer cranks <NUM> of <FIG> are arranged on opposing transverse (e.g., generally circumferential) sides of a respective one of the nozzle outer doors <NUM>. Referring to <FIG>, each outer crank <NUM> includes an outer crank base <NUM>, an outer crank first arm <NUM> and an outer crank second arm <NUM>. Referring to <FIG> and <FIG>, the outer crank base <NUM> is pivotally connected to the base structure <NUM> and its structure forward section <NUM> by a pivot connection <NUM>; e.g., a hinge connection, a pin connection, etc. Referring again to <FIG>, each of the outer crank arms <NUM> and <NUM> projects longitudinally out from the outer crank base <NUM> to a respective distal end. These outer crank arms <NUM> and <NUM> are angularly offset from one another about the outer crank base <NUM> and its pivot axis by an included angle; e.g., an acute angle.

The outer linkages <NUM> of <FIG> are arranged on opposing transverse (e.g., generally circumferential) sides of the respective nozzle outer door <NUM>. Referring to <FIG>, each outer linkage <NUM> may be configured as a fixed length link; e.g., a push rod, a strut, etc. Of course, in other embodiments, a length of each outer linkage <NUM> may be adjustable, but fixed during operation. Each outer linkage <NUM> extends longitudinally between and to an outer end of the respective outer linkage <NUM> and an inner end of the respective outer linkage <NUM>. Each outer linkage <NUM> is pivotally connected to the respective nozzle outer door <NUM> by a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) at the outer linkage outer end and at or about the outer door aft end <NUM>. Each outer linkage <NUM> is pivotally connected to a respective one of the outer cranks <NUM>. The outer linkage <NUM> of <FIG>, for example, is pivotally connected to the outer crank first arm <NUM> of the respective outer crank <NUM> through a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) at the outer linkage inner end and at the first arm distal end.

The intermediate linkages <NUM> of <FIG> are arranged on opposing transverse (e.g., generally circumferential) sides of the respective nozzle doors <NUM> and <NUM>. Each intermediate linkage <NUM> may be configured as a fixed length link; e.g., a push rod, a strut, etc. Of course, in other embodiments, a length of each intermediate linkage <NUM> may be adjustable, but fixed during operation. Each intermediate linkage <NUM> extends longitudinally between and to an outer end of the respective intermediate linkage <NUM> and an inner end of the respective intermediate linkage <NUM>. Referring to <FIG>, each intermediate linkage <NUM> is pivotally connected to a respective one of the outer cranks <NUM>. The intermediate linkage <NUM> of <FIG>, for example, is pivotally connected to the outer crank second arm <NUM> of the respective outer crank <NUM> through a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) at the intermediate linkage outer end and the second arm distal end.

Referring to <FIG>, the inner crank <NUM> includes an inner crank base <NUM>, one or more inner crank first arms <NUM> and one or more inner crank second arms <NUM>. Referring to <FIG> and <FIG>, the inner crank base <NUM> is pivotally connected to the base structure <NUM> and its structure aft section <NUM> by a pivot connection <NUM>; e.g., a hinge connection, a pin connection, etc. Referring to again to <FIG>, each of the inner crank arms <NUM> and <NUM> projects longitudinally out from the inner crank base <NUM> to a respective distal end. These inner crank arms <NUM> and <NUM> are angularly offset from one another about the inner crank base <NUM> and its pivot axis by an included angle; e.g., an acute angle. Each inner crank first arm <NUM> is pivotally connected to a respective one of the nozzle forward inner doors <NUM>. Each inner crank first arm <NUM> of <FIG>, for example, is pivotally connected to a respective mount <NUM> of the respective nozzle forward inner door <NUM> through a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) at its first arm distal end and at a distal end of the mount <NUM>, where the mount <NUM> of <FIG> is configured as a lever arm projecting out from a base panel of the respective nozzle forward inner door <NUM> to its distal end. Each inner crank second arm <NUM> is pivotally connected to a respective one of the intermediate linkages <NUM> through a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) at its second arm distal end and at the intermediate linkage inner end.

The actuators <NUM> of <FIG> are arranged on opposing transverse (e.g., generally circumferentially) sides of the respective nozzle doors <NUM> and <NUM>. Each actuator <NUM> may be configured as a linear actuator such as, but not limited to, a hydraulic cylinder. Each actuator <NUM> of <FIG> extends longitudinally between and to an outer end of the respective actuator <NUM> and an inner end of the respective actuator <NUM>. Referring to <FIG> and <FIG>, each actuator <NUM> is pivotally connected to the base structure <NUM> and its structure aft section <NUM> through a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) at the actuator outer end. Referring to <FIG>, each actuator <NUM> is pivotally connected to the inner crank <NUM>. More particularly, each actuator <NUM> is pivotally connected to a respective one of the inner crank second arms <NUM> by a pivot connection <NUM> (e.g., a hinge connection, a pin connection, etc.) proximate the respective second arm distal end; e.g., next to, but slightly radially outboard of the respective pivot connection <NUM>. With this arrangement, referring to <FIG>, each set of the nozzle doors <NUM>-<NUM> may be actuated / moved by the same one or more actuators <NUM> since (i) the inner crank <NUM> motively couples each actuator <NUM> to the respective nozzle inner doors <NUM> and <NUM> and (ii) the components <NUM>-<NUM> motively couple each actuator <NUM> to the respective nozzle outer door <NUM>.

<FIG> illustrate a sequence of the exhaust nozzle <NUM> moving from its first arrangement / first mode of operation to its second arrangement / second mode of operation to open the ejector passages <NUM>. During this movement, the actuators <NUM> longitudinally extend and thereby rotate the inner crank second arms <NUM> axially aft and rotate the inner crank first arms <NUM> laterally outward. Movement of the inner crank first arms <NUM> pulls the mounts <NUM> laterally outward and axially aft, which causes the respective nozzle forward inner door <NUM> to move and pivot laterally outward. Movement of the nozzle forward inner door <NUM> causes the respective nozzle aft inner door <NUM> to move and pivot laterally outward. Movement of the inner crank second arms <NUM> pulls the intermediate linkages <NUM> laterally inwards and axially aft, which causes the outer crank second arms <NUM> to rotate axially aft and the outer crank first arms <NUM> to rotate laterally inwards. Movement of the outer crank first arms <NUM> pull the outer linkages <NUM> laterally inward, which causes the respective nozzle outer door <NUM> to pivot laterally inward. The movement of the nozzle doors <NUM> and <NUM> respectively opens the respective ejector passage orifices <NUM> and <NUM> (see <FIG>).

The actuator assemblies <NUM> of <FIG> are described above with a plurality of each of the components <NUM>-<NUM>. However, in other embodiments, one or more or all of the actuator assemblies <NUM> may each be configured with a single one of each of the components <NUM>-<NUM>, where those components <NUM>-<NUM> are arranged transversely (e.g., generally circumferentially) midway along the respective nozzle outer door <NUM> and the respective nozzle forward inner door <NUM>.

In some embodiments, referring to <FIG> and <FIG>, the bottom half of the exhaust nozzle <NUM> may be configured as a mirror image of the top half of the exhaust nozzle <NUM>. However, in other embodiments, the bottom half of the exhaust nozzle <NUM> may have a different configuration than the top half of the exhaust nozzle <NUM>.

The exhaust nozzle <NUM> is shown in <FIG> with a polygonal (e.g., rectangular) tubular body. However, in other embodiments, it is contemplated the exhaust nozzle <NUM> may have alternative body geometries.

In some embodiments, one or more or all of the nozzle doors <NUM>-<NUM> may each be configured with a seal element or seal elements along a portion or an entirety of a perimeter of that door <NUM>, <NUM>, <NUM>. The seal element(s) may be configured as a pressure seal element and/or an aerodynamic seal element. For example, each of the nozzle outer doors <NUM> may be configured with a pressure seal element. Each of the nozzle inner doors may be configured with an aerodynamic seal element.

Claim 1:
An apparatus for an aircraft propulsion system (<NUM>), comprising:
an exhaust nozzle (<NUM>) including a flowpath (<NUM>), a passage (<NUM>), an outer door (<NUM>), an inner door (<NUM>) and an actuator (<NUM>) configured to move the outer door (<NUM>) and the inner door (<NUM>, <NUM>) between an open arrangement and a closed arrangement, wherein the outer door (<NUM>) closes an inlet (<NUM>) to the passage (<NUM>) when the outer door (<NUM>) is in the closed arrangement, and the inner door (<NUM>, <NUM>) closes an outlet (<NUM>) from the passage (<NUM>) when the inner door (<NUM>, <NUM>) is in the closed arrangement;
the flowpath (<NUM>) extending axially along a centerline (<NUM>) through the exhaust nozzle (<NUM>);
the passage (<NUM>) extending laterally into the exhaust nozzle (<NUM>) to the flowpath (<NUM>) when the outer door (<NUM>) and the inner door (<NUM>, <NUM>) are in the open arrangement; and
the outer door (<NUM>) configured to pivot inwards towards the centerline (<NUM>) when the outer door (<NUM>) moves from the closed arrangement to the open arrangement,
characterized in that:
the inner door (<NUM>, <NUM>) is configured to pivot outwards away from the centerline (<NUM>) when the inner door (<NUM>, <NUM>) moves from the closed arrangement to the open arrangement.