The present disclosure relates to systems for controlling movement of a divergent flap (24) in an exhaust nozzle (20). A nozzle flap assembly may include a first link (42) pivotably coupled to a divergent flap (24). A second link (40) may be pivotably coupled to the first link and a static portion (44) of the exhaust nozzle. The second link may comprise a bumper (50). The first link may be configured to contact the bumper in response to the divergent flap being in a high thrust mode. The second link may be configured to contact the divergent flap in response to the divergent flap being in a low thrust mode.

A variable area nozzle assembly for a gas turbine engine includes a nozzle disposed about a nozzle centerline and a fixed ring radially surrounding the nozzle. The nozzle includes a radially outer surface and a radially inner surface. The radially inner surface defines an outlet cross-sectional area of the nozzle. The nozzle is movable relative to the nozzle centerline between a first position of the radially inner surface defining a maximum area of the outlet cross-sectional area and a second position of the radially inner surface defining a minimum area of the outlet cross-sectional area. With the nozzle in the first position, the radially outer surface contacts the fixed ring. With the nozzle in the second position, the radially outer surface is spaced from the fixed ring.

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.

The invention concerns an aircraft propulsion control system in which a gas turbine engine has an actuable flow opening for control of flow to or from a portion of the engine. One or more sensor is arranged to sense a condition indicative of vapor trail formation by the exhaust flow from the engine. A controller is arranged to control actuation of the flow opening so as to reduce the efficiency of the engine upon sensing of said condition by the one or more sensor. In one example, the flow opening is a variable area fan nozzle.

Disclosed is a linkage assembly for a gas turbine engine having a link having a first end, a second end, and a rod extending therebetween, the first end having a first sliding bearing disposed within a first sliding bearing housing, a fastener comprising a first flange and a second flange, a pin extending between the first flange and the second flange, wherein the first sliding bearing is pivotally connected to the pin; and a biasing member secured between the first flange and the sliding bearing housing, the biasing member contacting the sliding bearing housing and biasing the link against rotation about a center axis for the rod of the link.

A gas turbine engine includes a compressor section, the compressor section including a variable inlet guide vane which is movable between distinct angles to control the airflow approaching the compressor section. A control is programmed to position the vane at startup of the engine to direct airflow across the compressor section. The engine includes a fan for delivering bypass air into a bypass duct positioned outwardly of a core engine including the compressor section. The position of the vane is configured to direct airflow across the compressor section while an aircraft associated with the gas turbine engine is in the air, and to increase a windmilling speed of the compressor section and the turbine rotors. A method and variable inlet vane are also disclosed.

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.

There is disclosed an exhaust nozzle for a gas turbine engine, the exhaust nozzle comprising a frame extending along a longitudinal axis. The exhaust nozzle comprises a convergent petal pivotably attached at a convergent pivot point to the frame and extending axially downstream and radially inward from the frame, 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 concave working surface such that a contact angle between the follower roller and the cam varies along the travel to thereby vary a radial component of the force reacted by the cam.

In some embodiments, apparatuses are provided herein useful to sealing a gap between a movable flap and a stationary structure, such as a gap between a gas turbine engine nozzle flap and a corresponding sidewall. An apparatus for sealing such a gap may be a dynamic skirted leaf seal which may include a flap arm and a wall arm opposite the flap arm. A distal end portion of the flap arm may comprise a first skirt and the distal end portion of the wall arm may comprise a second skirt that engages the first skirt. When positioned in a gap between the movable flap and the stationary structure, the skirted leaf seal may exert a force to urge the flap arm towards the flap and to urge the wall arm towards the structure to seal the gap.

An aircraft system is provided that includes a propulsion system structure and a variable area nozzle. The propulsion system structure includes a duct, and is adapted to move between a first position and a second position. The variable area nozzle is fluidly coupled with the duct. The variable area nozzle is adapted to move 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. The exit area of the variable area nozzle has a second value when the variable area nozzle is in the second configuration. Movement of the variable area nozzle between the first configuration and the second configuration is mechanically linked with movement of the propulsion system structure between the first position and the second position.