A variable area nozzle assembly for a gas turbine engine includes a fixed structure surrounding an exhaust duct extending along a nozzle centerline. The fixed structure includes an upper side and a lower side opposite the upper side. The variable area nozzle assembly further includes a nozzle disposed about the nozzle centerline. The nozzle includes a nozzle throat cross-sectional area and a nozzle outlet cross-sectional area downstream of the nozzle throat cross-sectional area. The nozzle includes an upper panel and a lower panel. The upper panel includes an upper downstream end and the lower panel including a lower downstream end. The upper downstream end and the lower downstream end define a portion of the nozzle throat cross-sectional area. The variable area nozzle assembly further includes a nozzle actuation system including an upper shaft connected to the upper panel and a lower shaft connected to the lower panel.

An apparatus is provided for an aircraft propulsion system. This apparatus includes a variable area nozzle apparatus. The variable area nozzle apparatus includes a plurality of panels, a plurality of inter-panel members and an actuation system. The panels are arranged circumferentially about an axial centerline. The panels include a first panel and a second panel. The inter-panel members are arranged circumferentially about the axial centerline. The inter-panel members include a first inter-panel member between and connected to the first panel and the second panel. The first inter-panel member is configured from or otherwise includes an elastomeric material. The actuation system is configured to move the panels and the inter-panel members between a restricted flow arrangement and an unrestricted flow arrangement. The actuation system includes a first linkage and a second linkage. The first linkage is coupled to the first panel. The second linkage is coupled to the second panel.

An apparatus is provided for an aircraft propulsion system. This apparatus includes an exhaust nozzle. The exhaust nozzle includes a flowpath, a passage, an outer door, an inner door and an actuator configured to move the outer door and the inner door between an open arrangement and a closed arrangement. The flowpath extends axially along a centerline through the exhaust nozzle. The passage extends laterally into the exhaust nozzle to the flowpath when the outer door and the inner door are in the open arrangement. The outer door is configured to pivot inwards towards the centerline when the outer door moves from the closed arrangement to the open arrangement. The inner door is configured to pivot outwards away from the centerline when the inner door moves from the closed arrangement to the open arrangement.

An aircraft system includes a propulsion system structure, a variable area nozzle and a linkage system. The propulsion system structure is moveable between a first position and a second position. The variable area nozzle is fluidly coupled with a duct in the propulsion system structure. The variable area nozzle is moveable between a first configuration and a second configuration. An exit area of the variable area nozzle has a first value when the variable area nozzle is in the first configuration and a second value when the variable area nozzle is in the second configuration. The variable area nozzle includes a flap moveably connected to the propulsion system structure. The linkage system mechanically links the variable area nozzle with the propulsion system structure. The linkage system includes a driver linkage, a first bell crank, a bridge linkage, a second bell crank, a follower linkage and a crank arm.

A turbofan gas turbine engine includes a core engine within a core nacelle, a fan nacelle at least partially surrounding the core nacelle to define a bypass flow path and a variable fan nozzle exit area for bypass flow, and a pylon variable area flow system which operates to effect the bypass flow. A method of operating a turbofan gas turbine engine is also disclosed.

Seals for gimbaling and/or fixed rocket engine nozzles, and associated systems and methods are disclosed. A representative rocket propulsion system includes a rocket engine having an exhaust nozzle, a seal plate carried by the exhaust nozzle, and a seal engaged with the seal plate. The seal includes at least one support, multiple pivotable first flaps, carried by the at least one support and positioned to contact the seal plate, and multiple pivotable second flaps, with an individual second flap positioned to shield a corresponding individual first flap. At least one forcing element is operatively coupled to at least one of the individual first flap or the individual second flap, to apply a pivoting force to the at least one of the individual first flap or the individual second flap.

There is disclosed an exhaust nozzle for a gas turbine engine. The exhaust nozzle comprises a frame extending along a longitudinal axis, and a convergent petal pivotably attached at a convergent pivot point to the frame and extending axially downstream and radially inward from the frame. The exhaust nozzle comprises a follower roller fixed to the convergent petal on a radially outer side of the convergent petal, and a cam defining a working surface configured to engage the follower roller to react a force from the convergent petal. The cam is movable along a travel in an axial direction to actuate radial movement of the follower roller to pivot the convergent petal. The cam defines a convex working surface such that a contact angle between the follower roller and the cam varies along the travel to thereby vary an axial component of the force reacted by the cam.

A turbofan gas turbine engine includes a core engine within a core nacelle, a fan nacelle at least partially surrounding the core nacelle to define a bypass flow path and a variable fan nozzle exit area for bypass flow, and a pylon variable area flow system which operates to effect the bypass flow. A method of operating a turbofan gas turbine engine is also disclosed.

There is disclosed an exhaust nozzle for a gas turbine engine. The exhaust nozzle comprises a frame extending along a longitudinal axis, and a convergent petal pivotably attached at a convergent pivot point to the frame and extending axially downstream and radially inward from the frame. The exhaust nozzle comprises a follower roller fixed to the convergent petal on a radially outer side of the convergent petal, and a cam defining a working surface configured to engage the follower roller to react a force from the convergent petal. The cam is movable along a travel in an axial direction to actuate radial movement of the follower roller to pivot the convergent petal. The cam defines a convex working surface such that a contact angle between the follower roller and the cam varies along the travel to thereby vary an axial component of the force reacted by the cam.

A nacelle assembly of a gas turbine engine includes an annular structure defining a central axis, and having a radially inward surface and a radially outward surface, the radially inward surface at least partially defining a bypass duct. An aft portion of the radially inward surface at least partially defines an axially extending convergent-divergent exit nozzle. A secondary nozzle flap is radially spaced from the aft portion of the radially inward surface. The secondary nozzle flap and the aft portion of the radially inward surface define a secondary bypass duct therebetween. The secondary nozzle flap is operably connected to the annular structure such that the secondary nozzle flap is selectably movable relative to the aft portion of the radially inward surface, thereby changing a cross-sectional area of a secondary bypass duct exit.