A gas turbine engine is provided. The gas turbine engine includes a core and a variable pitch fan arranged in flow communication with the core. The variable pitch fan has a disk and at least nine fan blades coupled to the disk for rotation together with the disk. The gas turbine engine further includes a rotatable nacelle covering the disk such that the engine has a fan hub radius ratio of between about 0.1 and about 0.4.

A method for reducing the noise level generated by a fan of a turbomachine including a plurality of vanes, said method further including, when the turbomachine is operating and under given flight conditions, the following steps measuring an operational pitch angle for each of the vanes, calculating an offset between the operational pitch angle of each of the vanes and a predetermined reference pitch angle for the given flight conditions so as to produce a controlled noise level at multiple rotation frequencies of the fan, correcting the orientation of the vanes so as to compensate their operational pitch angles depending on the offsets thus calculated.

The invention relates to an aircraft comprising a fuselage (1), which is propelled by a turbine engine with two coaxial fans, namely an upstream fan (7) and a downstream fan (8), driven by two contra-rotating rotors (5, 6) of a power turbine (3). The two fans (7, 8) and the turbine (3) are integrated into a nacelle (14) which projects downstream from the fuselage (1) and through which air flows. According to the invention, at least one of the fans (7, 8) of the aircraft and, in particular, the downstream fan (8) comprises variable-spacing blades, and at least one stator-forming variable-spacing blade ring (25) in the aircraft is placed upstream of the upstream fan (7). The variable-spacing stator blades (25) and the variable-spacing blades of the downstream fan (8) are mutually configured to direct the air flow in a first mode in which the air flows through the nacelle (14) from upstream to downstream and in a second mode in which the air is pushed back upstream through the nacelle (14).

The present disclosure includes vane assemblies having a vane lever arm with an inclined profile. The inclined profile may engage with a complementary end of a vane shaft to locate, retain, and prevent rotation of the vane shaft and vane.

A pitch actuation system for a turbine engine propeller includes an actuator with movable part configured to rotate the blades of the propeller relative to the blade pitch axes. The actuator includes a transmission screw that is rotatable and movable in translation along a longitudinal axis, and a nut that engages the screw to move in translation along the longitudinal axis to adjust the pitch of the propeller blades. The actuator further includes non-rotatable means for decoupling the rotation between the propeller and the nut. A blade feathering means has at least one electric drive motor and is configured to translate a member along the longitudinal axis. A blade pitch control means includes at least one electric motor configured to drive a rotor about the longitudinal axis, wherein that rotation rotates the screw and transmits translation of the member.

Pitch actuation system for a turbine engine propeller, comprising an actuator, a movable part of which is configured to be connected to blades of the propeller so as to rotate them relative to the blade pitch axes (B), comprising: a transmission screw that can rotationally and translationally move along a longitudinal axis (A), a nut, through which said transmission screw passes and which cooperates with this screw so as to translationally displace along the axis (A) with a view to modifying the pitch of the propeller blades, and means for decoupling between the rotation of the propeller and said nut, which is rotationally fixed; first blade pitch control means, which comprise at least one electric motor setting a component into rotation through a planet reduction gear with a view to modifying the position of the transmission screw; second blade feathering means configured to act on the transmission screw with a view to modifying the pitch of the blades if the first means are inactive, and in that said first planet reduction gear comprises a ring gear rigidly connected to said first component, a planet shaft rigidly connected to said first rotor and a planet carrier rigidly connected to said first housing.

A shrouded fan assembly for use with a gas turbine engine includes a central hub and a plurality of variable-pitch fan blades coupled to and extending radially outward from the central hub. Each variable-pitch fan blade includes a radially outer tip is rotatable about a longitudinal axis extending therethrough. A shroud is coupled to each radially outer tip.

A system is disclosed for measuring displacement of a regulation system for a variable pitch axial fan. The system includes a hub having a plurality of adjustable pitch fan blades. A hydraulic cylinder is connected to the hub. A piston is disposed within the hydraulic cylinder. The piston is coupled to a piston shaft that is axially movable with respect to the hub. The piston shaft is coupled to an actuation assembly for adjusting the pitch of the plurality of adjustable pitch fan blades in response to an axial movement of the piston. A rotating oil union includes a housing and an interior element, the interior element coupled to the hydraulic cylinder so that rotation of the cylinder and the hub causes rotation of the interior element. The rotating oil union includes a static housing and a central probe fixed to the static housing. The central probe extends through respective openings in the interior element, the hydraulic cylinder, and the piston. The central probe is configured to sense an axial position of the piston and to generate a signal representative of said axial position. A method for using the system is also disclosed.

The present application discloses a method for repairing a damaged counterbore in a variable vane shroud. A layer of base material is removed from the vane shroud adjacent the counterbore such that a damaged portion of the counterbore is removed. A shrink-fit insert having a size slightly larger than that corresponding to the layer of base material removed from the shroud is placed into the area of removed material such that the counterbore is restored to pre-damaged dimensions upon installation of the shrink-fit insert.

A fan for a gas turbine engine is provided. The fan includes a plurality of fan blades, a disk, and a trunnion mechanism for attaching the fan blades to the disk. The disk can be formed of a plurality of individual disk segments, with the trunnion mechanism attaching one of the plurality of fan blades to a respective disk segment. A retention member is also provided. The retention member includes a means for catching a portion of the trunnion mechanism should a primary attachment system of the trunnion mechanism fail.