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.

A gas turbine engine including a core having in serial flow order a compressor, a combustor, and a turbine—the compressor, combustor, and turbine together defining a core air flowpath. The gas turbine engine additionally includes a fan section mechanically coupled to the core, the fan section including a plurality of fan blades, and each of the plurality fan blades defining a pitch axis. An actuation device is operable with the plurality fan blades for rotating the plurality fan blades about their respective pitch axes, the actuation device including an actuator located outward of the core air flowpath to, e.g., simplify the gas turbine engine.

Conventional gas turbine engines are generally optimized to operate at nearly a fixed speed with fixed blade geometries for the design operating condition. When the operating condition of the engine changes, the flow incidence angles may not be optimum with the blade geometries resulting in reduced off-design performance. By contrast, according to embodiments of the present invention, articulating the pitch angle of turbine blades in coordination with adjustable nozzle vanes improves performance by maintaining flow incidence angles within the optimum range at all operating conditions of a gas turbine engine. Maintaining flow incidence angles within the optimum range can prevent the likelihood of flow separation in the blade passage and also reduce the thermal stresses developed due to aerothermal loads for variable speed gas turbine applications.

A variable pitch bladed disc including a plurality of blades, each being of variable pitch about a blade axis of rotation and having a root, the plurality of blades including at least one first blade and at least one second blade, a plurality of rotor connecting shafts, each shaft having a root and a tip, the root of each blade being mounted on the tip of a corresponding rotor connecting shaft via a pivot so as to allow each blade to be rotated about the blade axis of rotation, the first blade having a first rotation axis inclination such that the rotation axis thereof is inclined in a fixed manner with respect to a radial axis passing through the root of the corresponding shaft, and the second blade has a second rotation axis inclination different from the first rotation axis inclination.

Hydraulic pitch actuation mechanism includes vaned rotor within timing chamber surrounded by annular timing chamber wall within fan hub and variable area and volume retarding and advancing chambers within timing chamber. Timing pocket walls extend inwardly from timing chamber wall and interdigitated with timing vanes extending outwardly from vane shaft of vaned rotor. Hydraulic retarding and advancing fluid passages extend through fan drive shaft and through the fan hub to the retarding and advancing chambers respectively. Fluid passages include annular axially spaced apart retarding and advancing passage discharge sections, annular and axially spaced apart retarding and advancing passage entry sections spaced apart from and aft of retarding and advancing passage discharge sections respectively. Retarding and advancing connecting passage sections extend through fan drive shaft and fluidly connect retarding and advancing passage entry sections to retarding and advancing passage discharge sections. Hub passages through fan hub connect passage discharge sections to chambers.

A thrust propeller variable pitch actuator is controlled by a governor that uses propeller pitch as a variable to increase or decrease torque—not to maintain the propeller speed or RPM but instead to maintain certain established electric current supplied to rotate the thrust propeller.

A measurement system for determining an angular position of a component of a gas turbine engine includes one or more proximity sensors positioned at a fixed structure of the gas turbine engine and one or more sensor targets positioned at a rotatable component of the gas turbine engine. Each sensor target of the one or more sensor targets includes a target surface having a variable distance between the target surface and the proximity sensor with rotation of the rotatable component about a component axis of rotation. A measurement of distance between the proximity sensor and the target surface as measured by the proximity sensor is indicative of an angular position of the rotatable component relative to the component axis of rotation.

A propeller control unit (PCU) has: a pitch angle actuator; a valve operable to selectively fluidly connect the pitch angle actuator with a source of oil for controlling pitch angles of blades of a propeller and with a drain line for draining oil out of the pitch angle actuator for feathering the blades; and a bypass line having an inlet hydraulically between the valve and an inlet of the drain line, the bypass line having an outlet hydraulically between the inlet of the drain line and an outlet of the drain line.

Methods and system are described for operating an aircraft powerplant comprising an engine coupled to a variable-pitch propeller. The method comprises receiving a request to change a propeller rotational speed from a first setting to a second setting, determining a power need for the engine, when the power need corresponds to the second setting, modifying a command for at least one of fuel flow to the engine and oil flow to the propeller to govern the powerplant in accordance with the second setting for the propeller rotational speed, and when the power need does not correspond to the second setting, overriding the request to change the propeller rotational speed from the first setting to the second setting.

Variable-pitch blade control ring (44) for a turbine engine, including an annular body (42) configured to be mounted so as to be rotatable about an annular casing (16) of the turbine engine. The body links to levers (34) for connecting to the vanes. The ring has a mechanism for guiding in an axial and/or helical direction, supported by the body. The mechanism includes at least one substantially radial finger (60, 62) for axial abutment on at least one first surface (72, 74) of the casing and for sliding on the surface.