A control circuit for changing the angle of propeller blades includes a propeller control unit controlling a supply of oil to modify an angle of propeller blades, and a fixed-displacement pump providing the supply of oil from an engine oil return system to the propeller control unit. An oil cooling line extends between an outlet of the pump and the engine oil return system. The oil cooling line defines an oil leakage path leading to the engine oil return system for cooling the oil. A flow regulator between the pump and the propeller control unit is operable between an open position where oil is directed through the oil cooling line to the engine oil return system for cooling the oil, and a closed position blocking the oil cooling line and directing oil toward the propeller control unit to modify the angle of the propeller blades.

A blade for an industrial axial fan including an attachment and an airfoil having a longitudinal axis, the attachment connecting the airfoil to a hub, wherein the attachment has a stiffness and a stiffness distribution that allows the attachment to deform in a way to have at least an inflection point along the longitudinal axis during the operation of the axial fan. The attachment includes a first part for connection to the hub and a second part for connection to a proximal end of the airfoil. The blade further includes a weight fixed at a distal end of the airfoil. The attachment has a decreasing stiffness along its longitudinal direction from the first part to the second part so that during the operation of the axial fan, the attachment deforms and includes the inflection point to thereby induce the blade to vibrate according to a second vibrating mode.

The ideal design for a fan with variable performance that can replace a family of current axial flow ducted, un-ducted, and centrifugal fan designs by meeting air flow and pressure requirements while drawing less electric current to rotate and thus produce the required flow not only would reduce cost of operation over the life of the fan but opens new possibilities for direct connection to solar collection systems by greatly extending the life of the battery charge employed by the designer of the collection system. In addition the entry of flying machines using pairs of lifting fans such as hover bikes and quadcopters, manned or unmanned is driving a need to re-examine the application of force applied to rotate these fans to achieve a reduction in aircraft weight and increase flying time for a given battery charge or load of fuel.

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 device for controlling the pitch of fan blades in a turbine engine having an unducted fan including at least one set of adjustable pitch fan blades, each fan blade being coupled, for pitch adjustment purposes, to a radial control shaft constrained to rotate with the set of fan blades and suitable for pivoting about a radial pitch axis of the fan blade, the device including a stationary actuator centered on a longitudinal axis of the turbine engine and driving an outer ring of a load transfer bearing in translation, the outer ring of the load transfer bearing being coupled directly to a lever arm of each control shaft via a respective ball joint connection in order to adjust its pivoting.

An actuation system is provided for varying the pitch of the blades of a variable pitch fan or propeller. The actuation system includes a first actuator and a second actuator. The actuation system further includes a first linkage which operably connects the first actuator to the blades such that operation of the first actuator varies the pitch of the blades via the first linkage. The actuation system further includes a second linkage which operably connects the second actuator to the first actuator such that operation of the second actuator varies the pitch of the blades by series connection of the second linkage to the first linkage.

The variable pitch propeller assembly includes a hub. The variable pitch propeller assembly also includes a plurality of propeller blade assemblies spaced circumferentially about the hub. Each of the plurality of propeller blade assemblies configured to rotate a respective propeller blade. The variable pitch propeller assembly also includes a hydraulic fluid port assembly integrally formed and including at least three hydraulic fluid ports configured to receive respective flows of hydraulic fluid from a stationary hydraulic fluid transfer sleeve. The variable pitch propeller assembly also includes a pitch actuator assembly coupled in flow communication with at least three hydraulic fluid ports through respective hydraulic fluid transfer tubes. The pitch actuator coupled to the plurality of propeller blade assemblies to selectively control a pitch of the propeller blades. The pitch actuator assembly includes a travel stop configured to limit a rotation of at least one of the pitch actuator assemblies.

A fan module for an aircraft turbine engine includes a fan with a fan shaft and variable-pitch fan blades. The fan module further includes an oil transfer device transfers oil between a stator and an actuator that controls the pitch of the fan blades the device includes a stator ring having an inner cylindrical surface and internal oil ducts, each of which opens onto the inner cylindrical surface. A shaft is engaged in the stator ring and capable of rotating rotates about an axis inside the ring. The shaft includes an outer cylindrical surface extending inside said inner cylindrical surface. The shaft has internal oil ducts, each of which opens onto said outer cylindrical surface. A rolling bearing is mounted between the ring and the shaft, on each side of the plain bearing.

A fan control system for a variable pitch fan of a work vehicle includes a blade pitch module that adjust a pitch of a plurality of blades of the variable pitch fan to generate airflow in a first direction. A reversing module selectively commands a fan reversal that includes instructing the blade pitch module to temporarily adjust the pitch of the plurality of blades to generate airflow in a second direction. A first timer module, in response to the reversing module commanding the fan reversal, resets and increments a first timer and compares the first timer to a first threshold. A first reversal prevention module, in response to the first timer being less than the first threshold, prevents the reversing module from commanding a fan reversal by indicating that a first type of fan reversal is not permitted.

A fan module for an aircraft turbine engine includes a fan having variable pitch blades and an oil transfer device configured to provide a transfer of oil between a stator and a rotor. The oil transfer device includes a stator ring having internal oil ducts, a shaft inserted into the ring and having internal oil ducts, and an annular support of the ring configured to deform elastically to allow movements of the ring in the radial direction. A plain bearing is located between the ring and the shaft, and roller bearings are mounted between the ring and the shaft on either side of the plain bearing.