Methods, apparatus, systems and articles of manufacture are disclosed. An inner shroud damper for a gas turbine engine includes: at least one carrier including a joint to couple to an inner shroud, the at least one carrier having a first side and a second side, and at least one mass damper coupled to the at least one carrier.

A fan assembly includes a fan duct, an inlet fan, and an outlet guide vane assembly. The inlet fan includes blades adapted to force fan exit air toward an aft end of the fan duct. The outlet guide vane assembly is located in the fan duct downstream of the inlet fan and is configured to adjust a direction of the fan exit air received from the blades. The outlet guide vane assembly includes a first plurality of outlet guide vanes including a first outlet guide vane configured to rotate to a first angle so as to redirect the fan exit air in a first direction and a second outlet guide vane configured to rotate to a second angle so as to redirect the fan exit air in a second direction. The second outlet guide vane is located at a different circumferential position than the first outlet guide vane.

A fan assembly includes a fan duct, an inlet fan, and an outlet guide vane assembly. The inlet fan forces fan exit air toward an aft end of the fan duct. The outlet guide vane assembly is located in the fan duct downstream of the inlet fan and adjusts a direction of the fan exit air, and includes a plurality of outlet guide vanes and a plurality of actuation assemblies that control rotation of the outlet guide vanes about a pitch axis. The outlet guide vanes include a leading edge portion and a trailing edge portion rotatably coupled to an axially aft edge of the leading edge portion. The actuation assembly rotates the leading edge portion and the trailing edge portion to minimize losses created by distortions in fan inlet air and created by the leading edge portion redirecting the fan exit air in the first direction.

A turboshaft engine for a rotorcraft includes a first spool and an independently rotatable second spool. The first spool includes a low pressure compressor, a first set of variable guide vanes disposed at an entry of the low pressure compressor, and a low pressure turbine drivingly engaged to the low pressure compressor. The second spool includes a high pressure compressor, a second set of variable guide vanes disposed at an entry of the high pressure compressor, the second set of variable guide vanes independently operable relative to the first set of variable guide vanes, and a high pressure turbine drivingly engaged to the high pressure compressor. One or both of the low pressure compressor and the high pressure compressor includes a mixed flow rotor.

A turbomachine engine can include a fan assembly, a pitch change mechanism, a vane assembly, a core engine, a gearbox, and a gearbox efficiency rating. The fan assembly can include a plurality of fan blades. The pitch change mechanism can be coupled to the fan assembly. The vane assembly can include a plurality of vanes. The core engine can include one or more compressor sections and one or more turbine sections. The gearbox includes an input and an output. The input is coupled to the one or more turbine sections of the core engine and comprises a first rotational speed, the output is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 4.1-14.0. The gearbox efficiency rating is 0.10-1.8.

A gas turbine engine, has: an annular gaspath extending around a central axis, the annular gaspath defined between a first casing and a second casing, the first casing defining pockets; and a variable guide vane assembly having: variable guide vanes circumferentially distributed around the central axis, the variable guide vanes having airfoils extending into the annular gaspath and extending between first and second pivot members at respective first and second ends of the airfoils, the variable guide vanes rotatable about respective spanwise axes, bushings received within the pockets of the first casing, the first pivot members of the variable guide vanes rollingly engaged to the bushings, and resilient members disposed radially between surfaces of the first casing and the bushings relative to the spanwise axes, the resilient members in abutment against both of the surfaces of the first casing and the bushings.

Turnbuckle linkages are disclosed herein. A turnbuckle linkage includes an inside rod including a first opening on a first longitudinal end and a second opening on a second longitudinal end of the inside rod, the first opening and the second opening extending at least partially through the inside rod, the inside rod including tabs extending from the first longitudinal end and the second longitudinal end of the inside rod around the first opening and the second opening, an exterior surface of the tabs including conical threads, outside rods to be positioned within the openings of the inside rod, the tabs of the inside rod at least partially surrounding the outside rods, the outside rods including end bearings to couple to a first structure and a second structure, and conical nuts to constrict the tabs around the outside rods and couple the inside rod and the outside rods.

There is disclosed a centrifugal compressor including an impeller rotatable about an axis and a diffuser downstream of the impeller. The diffuser has walls delimiting flow passages. Plasma actuators are positioned adjacent the walls and are operatively connectable to a source of electricity. The plasma actuators have a first electrode, a second electrode, and a dielectric layer therebetween. The first electrode is upstream of the second electrode. The first electrode is exposed to the flow passage. The second electrode is shielded from the flow passage by the dielectric layer. The plasma actuators are operable to generate an electric field through the dielectric layer. The plasma actuators are located closer to inlets of the flow passage than to outlets of the flow passages. A method of operating the compressor is disclosed.

The invention relates to a guide vane assembly as well as to a method for mounting a guide vane assembly of a turbomachine, including a number of adjustable guide vanes, the guide vane platform of which has a guide vane journal that is mounted in a receiving opening of a housing of the turbomachine, wherein a guide vane head of the guide vane has a bearing pin, which is mounted on an inner ring arranged on a rotor of the turbomachine. In the method, a guide vane journal, which is arranged on a guide vane platform of a guide vane, is brought into a receiving opening of a housing, which is arranged radially with respect to a rotor axis of the turbomachine, and an inner ring is provided on a rotor of the turbomachine.

A unison ring of a gas turbine engine includes: an annular body including fiber-reinforced resin or circular-arc bodies including the fiber-reinforced resin, the fiber-reinforced resin including resin and reinforced fibers; and pin holes in which a pin is in a radial direction orthogonal to an axial direction of the unison ring. A main orientation of the reinforced fibers of the fiber-reinforced resin is directed in a circumferential direction of the unison ring.