A feedback sensor system is provided. The feedback sensor system includes a first ring rotatable about an axial direction and a second ring also rotatable about the axial direction. The first ring includes one or more first ring features and the second ring includes one or more second ring features. The feedback sensor system also includes a sensor directed at the surface of the first ring for sensing a parameter influenced by the one or more first ring features and the one or more second ring features. The sensor may determine a position of the first ring relative to the second ring by sensing the parameter.

A gas turbine engine includes a fan having a plurality of fan blades configured to rotate about a central axis of the gas turbine engine. Each fan blade is configured to pivot about a pitch axis that extends radially away from the central axis to vary a pitch of the fan blade.

A system for controlling the pitch of fan blades of a turbine engine propeller, the system including an actuator secured to a casing of the turbine engine, having a movable portion that is movable in translation relative to the casing, the movable portion being mechanically coupled to a load transfer bearing having an outer ring that is coupled to fan blade pivots so that a movement in translation of the movable portion of the actuator leads to a change in the pitch angle of the fan blades, and at least one locking peg secured to the casing of the turbine engine and suitable, in the event of the actuator malfunctioning, for mechanically locking the load transfer bearing in a position wherein the fan blades are feathered.

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.

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.

Gas turbine aircraft engine comprising an engine core comprising a turbine, a compressor, a core shaft connecting the turbine to the compressor; and a fan upstream of the engine core and driven by the turbine, the fan comprising a circumferential row of tandem fan blades. Each fan blade comprises a main blade and an auxiliary blade. Over substantially all of the auxiliary blade's radial span, the leading edge of the auxiliary blade is rearwards of the closest point on the trailing edge of the main fan blade, and on a given aerofoil chordal section of the main fan blade, the leading edge position of an aerofoil chordal section of the auxiliary fan blade lies on a rearwards extension of the camber line of the aerofoil chordal section of the main fan blade, and the main fan blade and the auxiliary fan blade are arranged to rotate in tandem.

A variable pitch blade holder for use with a gas turbine engine. The variable pitch blade holder is configured to retain a blade and to rotate about a center axis with the blade during operation of the gas turbine engine. The blade holder is adapted to rotate about a pitch change axis to vary a pitch of the blade.

A rotary machine comprises a hub including: a blade-facing hub portion including a first blade-facing surface which faces a spherical hub-side end surface of a variable blade and which has a first spherical region having a spherical shape; an upstream hub portion disposed upstream of the blade-facing hub portion in an axial direction of the hub and having a first outer-peripheral surface being adjacent to the first blade-facing surface in the axial direction; and a downstream hub portion disposed downstream of the blade-facing hub portion in the axial direction and having a second outer peripheral surface being adjacent to the first blade-facing surface in the axial direction. At least one of following condition (a) or (b) is satisfied: (a) a downstream end of the first outer peripheral surface is disposed on an outer side of an upstream end of the first blade-facing surface in the radial direction of the hub; (b) an upstream end of the second outer peripheral surface is disposed on an outer side of a downstream end of the first blade-facing surface in the radial direction of the hub.

A system having a variable diameter impeller device that is operable for reducing an energy consumption of a rotating fluid or gas pump by increasing the impeller diameter as a speed of the rotating fluid or gas pump increases and decreasing the impeller diameter as the speed decreases. An extendable vane arrangement is configured to move along an elongated curved or sloping slot, the movement along the elongated curved or sloping slot is operable for increasing and decreasing a diameter of the impeller device. A spring arrangement having a first end and a second end extends and retracts to dynamically increase or decrease a diameter of the impeller device.

A gas turbine engine includes a fan having a plurality of fan blades configured to rotate about a central axis of the gas turbine engine. Each fan blade is configured to pivot about a pivot axis that extends radially away from the central axis to vary a pitch of the fan blade. The fan further includes a counterforce system configured to resist forces that urge the fan blades away from their pitch positions during operation of the gas turbine engine.