Abstract: A sensor signal produced by a sensor as a feedback device rotates with a propeller about an axis and moves along the axis with adjustment of a blade angle of the propeller is received, the sensor signal indicative of a rotational speed and of the blade angle of the propeller. From the sensor signal, it is determined whether the rotational speed is within a predetermined range of a reference speed and an expected change in the blade angle has occurred in response to a command to adjust the blade angle to maintain the rotational speed at the reference speed. In response to determining that the rotational speed is within the predetermined range of the reference speed and the expected change in the blade angle has failed to occur in response to the command, inoperable movement of the feedback device along the axis is determined and an alert is output.

Abstract: An electronic control system for a turbopropeller engine having a gas turbine and a propeller assembly coupled to the gas turbine is provided. The control system implements a propeller control unit to control propeller operation using an actuation assembly designed to adjust a pitch angle of propeller blades. The control unit engages a mechanical lock determining a minimum flight value for the pitch angle during a flight operating mode, and disengages the mechanical lock and controls the pitch angle below the minimum flight value, up to a minimum ground value lower than the minimum flight value, during a ground operating mode. The propeller control unit, during a transition from the ground operating mode to the flight operating mode, engages the mechanical lock. The control unit anticipates the increase of the pitch angle before the mechanical lock engagement when transitioning from the ground operating mode to the flight operating mode.

Abstract: Methods and systems for operating an aircraft powerplant comprising an engine coupled to a variable-pitch propeller capable of generating forward and reverse thrust are described herein. A request to enable a mode for automated reverse thrust is received. Reverse thrust conditions are determined to have been met when the aircraft is on-ground, a blade angle of the propeller is below a blade angle threshold and a position of a power lever is at a selected idle region of the power lever. Reverse thrust of the propeller is triggered when the mode for automated reverse thrust is enabled and the reverse thrust conditions have been met.

Abstract: A hydraulic circuit for a wind turbine is provided. The hydraulic circuit includes: a fixed displacement pump including a suction input and a delivery output, a pump motor for driving the fixed displacement pump, a pressure line hydraulically connected to the delivery output of the fixed displacement pump for delivering an output flow and/or an output pressure generated by the fixed displacement pump towards at least a consumer circuit, a bypass valve including a valve input hydraulically connected to the delivery output of the fixed displacement pump, wherein the bypass valve includes a variable opening for controlling the output flow or the output pressure delivered by the fixed displacement pump towards the consumer circuit(s).

Abstract: A wind-turbine rotor blade, comprising a blade root and a blade tip, a flange arranged on the blade root side for fastening the rotor blade to a rotor hub of a wind turbine, and a pitch bearing for adjusting the angle of attack of the rotor blade. The rotor blade has a non-pitched carrier, on which the flange is embodied, wherein the pitch bearing is fastened to the carrier and is spaced apart from the flange toward the blade tip.

Abstract: A compression inner core cowl for a jet engine can have a concave annular section of the core cowl. The concave section can begin within the expanse of an outer fan cowl and extend aft of the fan cowl toward the tail cone, defining an annular bypass section between the fan cowling and the core cowling. The concave geometry of the core cowling reduces the strength of supersonic shock waves generated at the corners of the cowlings adjacent a supersonic airflow stream to increase overall efficiency of the engine.

Abstract: In one aspect, the present disclosure is directed to a gas turbine starting system that includes a shaft coupling a compressor and a turbine. An annular housing extends circumferentially around the shaft such that the annular housing defines a compartment. A flange extends radially outward from the annular housing for mounting the annular housing to a stationary wall. A starter is positioned in the compartment. A collar rotatably couples to the annular housing and selectively couples to the starter. The collar includes a radially inner surface having a plurality of splines for engaging the shaft. The starter, when activated, rotates the collar, which rotates the shaft to start the gas turbine.

Abstract: An oil transfer assembly supplies oil into a moving, rotating tube extending along an axis. The assembly is provided with a support plate transversal to the axis and a sleeve, which is angularly fixed with respect to the support plate, it is configured to be coupled in a sliding and watertight way to a terminal section of the inlet of said tube and has at least one chamber for transferring oil into said terminal section of the inlet. The assembly is also equipped with at least two tubular bodies, which project axially from the support plate, define between them an annular channel communicating with the chamber and join the sleeve to the support plate in a watertight manner and with clearances so as to leave freedom of orientation of the sleeve around any direction orthogonal to the axis.

Abstract: The main aim of the invention is a propeller (32) for a turboengine (1) comprising a plurality of blades (48) and a blade support ring (47) provided with housings (50), each receiving a pivot (52) bearing the foot (58) of one of said blades (48), characterized in that at least one of the pivots (52) is equipped with at least one counterweight system (90, 91) provided with at least one inner channel (93, 96) for airflow ventilation discharge (F1, F3) for capturing and guiding said airflow directly in contact with the blade foot (58) borne by said at least one of the pivots (52).

Abstract: The device is intended to supply a rotating linear displacement actuator capable of controlling the pitch of the blades of a propeller, according to separate operating states, from a rotary power assembly, the device being arranged so as to be located between the power assembly and the actuator, along a longitudinal axis, and being connected in rotation therewith. According to the invention, the device comprises supplies for supplying fluid interacting with the power assembly and defining as many supplies as there are operating states of the actuator, and a fluid distributor to which the supplies are connected and having separate channels for transporting the fluid in the direction of the actuator according to the operating states, by a tubular equipment connected to the distributor.

Abstract: An apparatus, for example for a pitch change mechanism, includes a cylinder having a magnetic portion defining an annular array of features extending parallel to the longitudinal axis of the cylinder, the cylinder rotating in use and able to translate longitudinally. There is a sensing arrangement including a stationary magnetised core and two coils connected in series and wound around the core. In use, the cylinder rotates and current is induced in the coils. Monitoring equipment is arranged to calculate rotational speed of the cylinder from the frequency of the current and to calculate longitudinal position from the relative amplitude of the current in each coil. Also a method.

Abstract: A vent valve according to an exemplary aspect of the present disclosure includes, among other things, a sensing sleeve defining a sensing chamber and a vent channel for venting fluid out of the sensing chamber. A sensing piston is moveable within the sensing chamber between an open position and a closed position. The sensing piston allows flow of the fluid into the vent channel during movement of the sensing piston between the open and closed positions.

Abstract: A variable pitch system for a water or wind turbine includes a hydraulic system that includes a first hydraulic system and a second, redundant hydraulic system that are completely contained in a nose region of the turbine. The first and second hydraulic systems can each be used during operation on a predetermined operating schedule. In addition, each of the first and second hydraulic systems can also include a pressure relief valve to limit back pressure on the hydraulic system from dynamic loads on the turbine blades. The pitch of all the blades are changed simultaneously using a common linear to rotary actuating mechanism. To aid in cooling, the hydraulic reservoirs for the first and second hydraulic systems can be attached to the front wall of the nose housing, and fins can be provided on the exterior of the nose housing at the front end to enhance heat extraction.

Abstract: There is provided a turbine for a hydroelectric power plant comprising a hub, a plurality of turbine blades provided on the hub, a pitch angle adjusting unit coupled to the turbine blades for adjusting the pitch angle of the turbine blades, a double-acting hydraulic cylinder and a piston rod connected thereto. The piston rod is coupled to the pitch angle adjusting unit in such a way that the pitch angle adjusting unit performs a rotational movement when the piston rod is moved in the longitudinal direction. The double-acting hydraulic cylinder is provided in a hydraulic chamber coupled by way of a first and a second hydraulic line so that the double-acting hydraulic cylinder is displaceable by feed of a hydraulic fluid through the first or second hydraulic line and thus leads to adjustment of the pitch angle of the turbine blades by way of the coupling to the piston rod and the pitch angle adjusting unit.

Abstract: The present invention relates to a hydraulic pitch system for pitching a blade of a wind turbine having a hub by means of a hydraulic fluid. The system comprises at least one hydraulic cylinder for adjusting a pitch angle of the blade, the hydraulic cylinder comprising a pitch piston movable in the hydraulic cylinder, and a first port and a second port arranged on each side of the pitch piston, and an accumulator hydraulically connected to the cylinder. The system further comprises a pitch safety system adapted to maintain the blade in a predetermined pitch angle when a person is entering the hub of the wind turbine for service and/or maintenance, the pitch safety system comprising a first valve which by activation releases a pressure in the hydraulic pitch system by draining off the accumulator for the hydraulic fluid until the pressure has reached a predetermined pressure level.

Abstract: A wind turbine comprises a hub, a blade rotatably mounted to the hub, and a pitch system. The pitch system includes a support, a first drive configured to rotate the blade relative to the support, a second drive configured to rotate the support relative to the hub. The support is configured to be selectively fixed relative to the blade and the hub such that the first or second drive may be used to pitch the blade. A method of pitch corresponding to this operation is provided.

Abstract: A link pin exchanging device for a wind turbine generator that can efficiently carry out exchange of the link pin in the rotor hub, and a link pin exchanging method. The link pin exchanging device comprises an actuator for moving the link pin so that the link pin disengages from the link mechanism, and a reaction force receiving member for receiving a reaction force that acts on the actuator, independent from the wall surface of the rotor hub that intersects with the operating direction of the actuator.

Abstract: A disc rotor blade retraction system includes a main blade spar incorporating a hydraulic cylinder and having a screw thread. A ball screw is concentrically carried within the main blade spar and is operably connected to a ball nut which has an outboard end connected to an intermediate spar with a hydraulic piston received for reciprocation in the hydraulic cylinder. A first geared actuator engages the ball screw and a second geared actuator engages the main blade spar screw thread. A hydraulic fluid accumulator providing pressurized hydraulic fluid is connected to an outboard end of the hydraulic cylinder and a controller actuates the first and second geared actuators.

Abstract: The device (18) is intended to supply a rotating linear displacement actuator capable of controlling the pitch of the blades of a propeller, according to separate operating states, from a rotary power assembly, the device being arranged so as to be located between the power assembly and the actuator, along a longitudinal axis (A), and being connected in rotation therewith. According to the invention, the device comprises means (20) for supplying fluid interacting with said power assembly and defining as many supplies as there are operating states of the actuator, and a fluid distributor (21) to which said supplies are connected and having separate channels for transporting the fluid in the direction of the actuator according to the operating states, by means of tubular equipment (25) connected to the distributor.

Abstract: A system for controlling at least two variable geometry apparatuses of a gas turbine engine that includes at least a first body and a second body, the first apparatus including a stator blade stage with a variable setting angle of a compressor of the first body capable of switching between a closed position in an idle mode and an open position in a high-speed mode, and the second apparatus including at least one discharge valve of a compressor of the second body capable of switching between an open position in an idle mode and a closed position in a high-speed mode. The system further includes an actuator for actuating the two apparatuses.

Abstract: A back-up featherer is provided for an engine arrangement having a main hydraulic actuator which angularly displaces propellers of a propeller assembly of the engine arrangement. The back-up featherer has a back-up hydraulic actuator for angular displacement of the propellers, the back-up hydraulic actuator rotating with the propeller assembly. The back-up featherer further has one or more back-up fluid supply lines for transferring hydraulic fluid between a hydraulic pressure power source located on a static structure of the engine arrangement and the back-up hydraulic actuator. The back-up featherer further has a back-up hydraulic rotating coupling, the back-up fluid supply lines fluidly communicating with the back-up hydraulic actuator via the back-up rotating coupling. A static side of the back-up hydraulic rotating coupling is mounted to the static structure of the engine arrangement, and a rotating side of the back-up hydraulic rotating coupling rotates with the propeller assembly.

Abstract: A blade pitch control mechanism for a propeller assembly (10) includes an actuation shaft (24) having a spherical member (28) located at a propeller axis (22). A yoke (40) is located around the spherical member (28) and is rotatable thereon about a yoke tilt axis (62) substantially perpendicular to the propeller axis (22). The yoke (40) includes a plurality of propeller blade attachments (44), each receptive of a propeller blade (14). The plurality of blade attachments (44) are configured such that rotation of the yoke (40) about the yoke tilt axis (62) results in rotation of each propeller blade (14) about a blade pitch change axis (48).

Abstract: A propeller system includes a plurality of propeller blades and a pitch lock mechanism operably connected to the plurality of propeller blades. The pitch lock mechanism includes a pitch lock chamber and a pitch lock piston located in the pitch lock chamber biased toward a locked position when there is insufficient pressure in the pitch lock chamber thereby locking the pitch of the plurality of propeller blades. The propeller system includes a pitch unlock mechanism including a pitch unlock housing and a pitch unlock piston disposed in the pitch unlock housing. A fitting extends through the propeller system to the pitch unlock housing and introduction of fluid flow into the pitch unlock housing through the fitting urges the pitch unlock piston into contact with the pitch lock piston to overcome the bias of the pitch lock piston thereby unlocking the pitch of the plurality of propeller blades.

Abstract: A frame for supporting equipment arranged in a hub of a wind turbine is fixed to the hub at one end and flexibly connected to the hub at another end. The variation of the relative position between the hub and the frame caused by the deformation of the hub associated with a rotation of the wind turbine or the like is absorbed by the flexible connection. A wind turbine whose frame in the hub has high durability against the rotation can be provided.

Abstract: A link pin exchanging device for a wind turbine generator that can efficiently carry out exchange of the link pin in the rotor hub, and a link pin exchanging method. The link pin exchanging device comprises an actuator for moving the link pin so that the link pin disengages from the link mechanism, and a reaction force receiving member for receiving a reaction force that acts on the actuator, independent from the wall surface of the rotor hub that intersects with the operating direction of the actuator.

Abstract: A turboprop having a set of variable-pitch rotary blades constrained to rotate with a rotary support. In order to vary its pitch, each blade of said set is coupled to a specific hydraulic actuator carried by the rotary support.

Abstract: A system for providing variable pitch to a rotor blade of an aircraft engine includes a rotatable hub; at least one blade mounted on the rotatable hub; a gear mechanism operably connected to the rotatable hub; a timing ring rotatably and operably connected to the gear mechanism; and a pitch arm operably connecting the timing ring and the at least one blade mounted on the rotatable hub. In the operation of the system, the gear mechanism facilitates the rotation of the timing ring to vary the pitch of the at least one blade mounted on the rotatable hub.

Abstract: A rigid hydraulic control shaft for conveying a fluid from a hydraulic valve to a hydraulic chamber of a propeller comprises a main segment. The main segment has a hollow rigid outer tube and a solid rigid inner bar. The inner bar has an outer periphery and at least one longitudinal groove disposed along the outer periphery. The outer periphery is configured to move in rotation and translation with an inner periphery of the outer tube. The main segment is configured to move in rotation and in translation with a piston disposed adjacent to the hydraulic chamber.

Abstract: A blade pitch control mechanism for a propeller assembly (10) includes an actuation shaft (24) having a spherical member (28) located at a propeller axis (22). A yoke (40) is located around the spherical member (28) and is rotatable thereon about a yoke tilt axis (62) substantially perpendicular to the propeller axis (22). The yoke (40) includes a plurality of propeller blade attachments (44), each receptive of a propeller blade (14). The plurality of blade attachments (44) are configured such that rotation of the yoke (40) about the yoke tilt axis (62) results in rotation of each propeller blade (14) about a blade pitch change axis (48).

Abstract: A system for adjusting the pitch of a variable pitch propeller has a hub assembly, a valve assembly, and a fluid supply assembly. The hub assembly comprises a hub rotatably driven by a propeller shaft, an actuator connected to the hub, and a plurality of propeller blades connected to the actuator with at least one mechanical connection. The valve assembly is in fluid communication with the valve assembly and the actuator. The fluid supply assembly comprises a valve control mechanism that is isolated from the valve assembly and the hub assembly. The valve control mechanism provides a variable hydraulic pressure control signal to the valve assembly, which transfers fluid to the actuator as a function of the variable hydraulic pressure control signal. Based on the fluid pressure in the actuator, the pitch of the propeller blades is adjusted.

Abstract: An apparatus for hydraulically adjusting the blades of an impeller of an axial-flow fan, comprising an adjustment cylinder that on both sides of a piston displaceably disposed in the cylinder has a first chamber and a second chamber respectively provided with a connection to control oil lines connected to four-way valves. Not only a feed line leading to one of the control oil lines, but also a return line connected to the other control oil line, is each divided into two parallel branch lines. Two redundant four-way valves are provided, each being disposed in one of the parallel branch lines. Disposed in each branch line of each control oil line, between the respective connection and the respective four-way valve, is a seat valve that closes by spring force.

Abstract: A variable pitch propeller has a centrifugal lock for blocking blade pitch changes from a normal range of forward pitch angles toward both feathered and reverse positions at rotational speeds greater than a predetermined threshold. The lock mechanism has a pair of stop members rigidly connected to a rack yoke member that has geared engagement with respective propeller blade pinions, and a pair of mass elements that move outwardly in response to centrifugal force to block movement of the lock members outside of the normal range. A pair of springs are connected between the mass elements for biasing them inwardly from paths of the lock members. The yoke is displaced axially by an actuator having an annular hydraulic cylinder. A hydraulic control unit having a motorized leadscrew coupled to another annular hydraulic cylinder is fluid coupled to the actuator, and a simple control circuit provides colored indications of pitch settings.

Abstract: A variable pitch propeller has a centrifugal lock for blocking blade pitch changes from a normal range of forward pitch angles toward both feathered and reverse positions at rotational speeds greater than a predetermined threshold. The lock mechanism has a pair of stop members rigidly connected to a rack yoke member that has geared engagement with respective propeller blade pinions, and a pair of mass elements that move outwardly in response to centrifugal force to block movement of the lock members outside of the normal range. A pair of springs are connected between the mass elements for biasing them inwardly from paths of the lock members. The yoke is displaced axially by an actuator having an annular hydraulic cylinder. A hydraulic control unit having a motorized leadscrew coupled to another annular hydraulic cylinder is fluid coupled to the actuator, and a simple control circuit provides colored indications of pitch settings.

Abstract: An adjustable pitch boat propeller system adapted for mounting on a drive shaft of a marine drive unit of a boat. The propeller includes an hub that has been adapted for mounting over the drive shaft of the boat, the hub having an external surface and internal annular surface. An annular piston is mounted against the internal annular surface and connected to a plurality of blades which are pivotally connected to the external surface of the hub by way of a linkage that allows pivoting the plurality of blades in response to movements of the annular piston.

Abstract: A controllable pitch propeller device is provided with a pitch locking system that prevents a controllable pitch propeller blade from being inadvertently forced to an extreme end of travel in the event that hydraulic pressure is lost in either of two conduits or as a result of a pump failure. The hydraulic pressure in each of two conduits is used to overcome a check valve in the opposite conduit to allow return hydraulic fluid flow through that opposite conduit. In the event of a loss of hydraulic pressure, the pressure needed to overcome the check valve is absent and the check valve operates normally to block return flow to a source of hydraulic pressure, such as a pump. This blockage of return flow, in turn, prevents a hydraulically responsive element, such as a piston, from moving subsequent to the loss of pressure.

Abstract: A system for controlling propeller blade pitch is disclosed. The system comprises a transfer tube, wherein the transfer tube defines an element of the rotatable portion and wherein the transfer tube is non-translating relative the rotatable and non-rotatable portions. A transfer bearing for providing hydraulic fluid to and interfacing with the transfer tube is also used, wherein the transfer bearing is located on the non-rotatable portion. The system further includes a pitch change actuator and a mechanism form for actuating the pitch change actuator, wherein the mechanism is fluidically connected to and translatable relative to the transfer tube. A device for measuring blade angle of the propeller blade is also provided, wherein the device is separate and distinct from the transfer tube.

Abstract: The hydraulic propeller system of the present invention has a central hub including a stationary portion and a rotatable portion. A plurality of propeller blades are connected with the rotatable portion, wherein each of the plurality of propeller blades has an adjustable pitch and a counterweight biasing the blades in a first pitch direction. An actuating mechanism is used for adjusting the pitch of each of the plurality of propeller blades. And a valve for locking the propeller blades at a last commanded pitch is further provided. At least the valve and the actuating mechanism are located on and rotatable with the rotatable portion.

Abstract: The invention concerns a system for controlling an aircraft propeller. A hydraulic motor controls pitch of the propeller blades. The propeller blades are characterized by the absence of feather-inducing counterweights. An overspeed governor senses when propeller speed exceeds a limit, and, in response, assumes control of the hydraulic motor and drives the blades toward a coarsened pitch position, which reduces the propeller speed. In another form of the invention, a mechanical brake can override the hydraulic motor and mechanically retard a rotating gear, which causes the propeller blades to move toward a coarsened pitch.

Abstract: A pitch change actuation system for changing the pitch of the blades (16) of a prop-fan propulsor (10) comprises a translating pitch change actuator (30) and a flexible feather latch member (50) including a feather stop (56) and a feather latch (58), the feather latch member (50) being selectively releasable so as to permit the pitch change actuator (30) to drive the blades (16) through feather to a desired reverse pitch setting. Pitchlock lugs (96) and (98) operatively engage a pitchlock screw lug (97) on a pitchlock screw (80) to provide pitchlock screw stops at full reverse pitch and feather, respectively, with the pitchlock lug (98) being selectively displaceable so as to permit the pitchlock screw (80) to rotate when the pitch change actuator (30) is translated to drive the blades (16) through feather to reverse pitch.

Abstract: An inboard servo for a controllable pitch propeller of the force rod type comprises a feedback device having at least two feedback rods connected to the piston and extending through the cylinder end wall and an output ring connected to the rods. An emergency lock-up includes at least two threaded locking rods fastened to the cylinder and passing freely through holes in the feedback ring, each of which receives one or more nuts that can be threaded along the rod for engagement with the feedback ring to lock the piston in a desired position.

Abstract: A bladed rotor assembly comprising:a bladed rotor;an actuator for effecting a change of blade pitch;a first valve member connected to, and movable with, the actuator and having first and second passageways;anda second valve member co-operable with the first valve member and having first and second passageway systems formed therein for communication with the first and second passageways of the first valve member.The first passageway system of the second valve member includes first and second independent passageways, and is provided with a valve, and a bypass incorporating a non return valve. The valve is positioned so that when in a closed position fluid is prevented from entering the first independent passageway.

Abstract: An overspeed protection system is provided for a turboprop engine. The engine includes a governor pump and a constant speed governor both of which are driven by the turbine through a gear reduction assembly. The constant speed governor is in communication with the pitch adjustment means of the propeller and is operative to effect adjustments in the propeller pitch. The system further includes a pressure sensitive switch that is operative to sense a decrease in pressure of the fluid flow produced by the governor pump and thereby sensing a system failure. A solenoid is provided and is operative to prevent pitch adjustments after a system failure sensed by the pressure sensitive switch.

Abstract: An impulse activated and controlled variable pitch propeller whereby the complete high pressure hydraulic system is incorporated in propeller hub assembly, including two identical type reciprocating hydraulic pumps which operate and control the propeller blade pitch settings by low force linear mechanical impulses transmitted from a remote stationary source through a pronged lever with input arm pivoting two anti-friction radial bearings attached to the pronged output ends for transmitting two equally balanced radial bearing contact forces in parallel on a rotating slidable flanged sleeve mounted on a propeller shaft adapter between the engine and the propeller, whereby said linear mechanical impulses are transmitted only during pitch change to actuate said pumps with the propeller otherwise free of any external mechanical contact during rotation.

Abstract: A propeller hub supports a plurality of adjustable pitch propeller blades which are rotated by a hydraulic cylinder and control system between a feather position and a reverse position through low and high pitch positions. The reverse pitch position is precisely set by axially adjusting a tubular sleeve threadably connected to the hydraulic cylinder and having an inner end surface forming a stop for the piston within the cylinder. The feather position is precisely set by axially adjusting lock nuts mounted on a threaded end portion of the piston rod projecting forwardly beyond the forward end of the sleeve. The hub also encloses feedback control rods which carry externally adjustable nuts providing for pilot control of the blade pitch into the reverse position.

Abstract: A variable pitch propeller, particularly suited for use with turbine engines, includes a range of beta control in low pitch and reverse pitch positions, in which the pilot can obtain a ground angle range with substantially lower angles in relation to the flight idle position. This is accomplished by the provision of lost motion connections in the form of sliding sleeves mounted on the beta feedback rods which come into operation at a particularly defined low pitch angle, under control of the pilot, and permits the blades to move to a still lower pitch angle for ground operations, by providing for relative movement between the blade yoke and the beta feedback rods.

Abstract: Apparatus for adjusting and locking the pitch of a variable pitch propeller. Within a propeller shaft, a hydraulic piston is provided which drives a rod, a plate, and levers to rotate the propeller blades in, and with respect to, the hub of the propeller. The root of the propeller within the hub has a conical portion which has a mating conical ring thereabout. This conical ring is engaged and locked into place with the conical portion of the propeller root and the propeller hub by hydraulic oil pressure, once the optimum pitch of the propeller blades is determined.

Abstract: In a vehicle or device a fluid motor is employed to drive rotary members, such as wheels, propellers, tracks. The motor is provided with an arrangement which includes a control means and an axially moveable member. By utilizing the control means for example by a flow of fluid, the axially moveable member is used to apply an action, which is not common to the usual operation of fluid motors. The arrangement may be used to arrest the rotor of the motor from rotation, when no pressure is in the driving fluid line. It may also be used to control the pitch of propellers with variable pitch arrangements. Also possible is to use the arrangement to automatically obtain an auto-rotation of rotor blades on vertical axes of vertically take off and landing vehicles, when the pressure in the fluid line to the motors for driving the motors drops below a predetermined minimum of pressure.

Abstract: A variable pitch propeller hub with fluid motor actuating means wherein blading is controllably pitched and feathered by a hub having cylinder and piston means responsive to engine oil pressure and rotating the blades on their radial axes to a full pitch position by link and lever means biased toward a feathered position by an adjustor means having adjustable stops and means for maintaining moderate pitch until the engine is stopped.

Abstract: A variable pitch propeller is controlled by a hydraulic mechanism responsive to forces urging an unsymmetrically mounted propeller towards its maximum pitch. Spring bias means maintains the propeller at minimum pitch under conditions of rest. The propeller is prevented from increasing its pitch by the pressure produced on a closed hydraulic chamber until it reaches a predetermined r.p.m., when a centrifugal valve opens a first port and relieves the pressure in the cylinder and allows the propeller to increase in pitch. The increase in pitch opens a second port communicating with the pressure chamber, but that channel remains closed by a second valve that is normally closed but opens in response to a reduction in the throttle setting. The reduction in throttle setting closes the centrifugal valve so that the only channel from the pressure chamber is through the second port.

Abstract: Wind turbine blade pitch control system including hydraulic actuators which pivotally drive the blades about the longitudinal axis thereof to adjust the blade pitch. The actuators are supplied with hydraulic fluid from independent sources thereof for normal blade pitch adjustment and feathering. Means are provided which, during feathering, isolate the pressurization and drain of the actuators from certain system components, whereby such pressurization and drain are not hampered by any malfunction of such components.