Abstract: Wind turbine pitch actuator mounting structure A mounting structure is described for attaching a pitch actuator to a hub of a wind turbine. The mounting structure has one or more legs each having a proximal end and a distal end, and a flexible intermediate portion between the proximal and distal ends. The mounting structure further comprises an actuator attachment portion for attaching to a wind turbine blade pitch actuator. The actuator attachment portion is arranged at the distal end(s) of the one or more legs. The proximal end(s) of the one or more legs are configured for attachment to a wind turbine hub. The flexible intermediate portion(s) of the one or more legs are configured to flex in use to absorb loads acting on the pitch actuator. The mounting structure therefore allows the pitch actuator to pivot in a first plane by virtue of the flexible legs.

Abstract: 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.

Abstract: Systems and methods are disclosed for controlling the pitch angle of a propeller and rotor assembly that minimizes circumferential loads and stresses to a pitch angle control system. The system may generally include an annular actuator, load transfer bearing (LTB), and a guide shaft is pivotally attached to the LTB to direct the LTB along an arcuate path relative to a rotor frame.

Abstract: A wind turbine, including a hub, a blade, a blade bearing which is connected to the hub and which enables a rotational movement of the blade relative to the hub, and an adjustment device for adjusting a pitch angle of the blade, wherein the adjustment device includes at least one actuator and wherein an effective direction of an adjustment force of the at least one actuator when adjusting the pitch angle of the blade is tilted in an angle relative to a bearing plane of the blade bearing. One advantage of the wind turbine is that the adjustment force for adjusting the pitch angle is transmitted directly into the blade bearing or the bearing plane. Further, an offset of the attacking point of the adjustment force can be reduced or completely avoided.

Abstract: A bi-directional contra-rotating circular rail bearing Y-shaped compound blade fluid energy collection multi-unit power generating windmill, the windmill comprising: a windmill remote automatic control system (1); a Y-shaped compound blade (2) from a combining of single blades; a circular rail windmill body (3) bearing the Y-shaped compound blade (2); a circular windmill rail (4) bearing the circular rail windmill body (3) for operation; a circular rail connection cable pulling vehicle (5) running on the circular cable pulling vehicle rail to pull the circular rail windmill using a stay cable (209); a hydraulic energy collection multi-unit power generating system (6) or pneumatic energy collection multi-unit power generating system (7); the Y-shaped compound blade (2) is born by three circles of the circular rail windmill body (3) arranged equidistant thereon; the circular rail windmill body (3) has six circles.

Abstract: A drive assembly includes a drive motor at least in part contained in a housing and having a rotor rotating an output shaft. A selector mechanism, at least in part contained in the housing, is movable into one of a plurality of orientations corresponding to one of a plurality of drive motor settings. An actuator, at least in part contained in the housing, is arranged to move the selector mechanism into one of the plurality of orientations. The actuator has first and second pistons each disposed in a piston chamber of the housing for movement by hydraulic pressure. The second piston is arranged in contact with the first piston and configured to aggregate and transfer forces from hydraulic movement of the first piston and the second piston to move the selector mechanism.

Abstract: The invention concerns a device (1) for controlling the pitch of the blades of a fan (4) rotor (3), comprising a radial shaft (6) linked to the blade, a connection rod (8) of which the axial movement controls the rotation of the radial shaft (6), characterized in that it comprises:—a first part (10) that is mobile in rotation with the rotor (3) about the axis (11) of the fan (4), and on which one end of each connection rod (8) is secured,—a second part (12) linked to the first part (10), and—at least three cylinders (14) capable of moving said second part (12) in axial translation, and of varying the tilt of said second part, the translation and tilt of the second part (12) driving a corresponding translation and tilt of the first part (10), such that, when the first part (10) rotates, each connection rod (8) is subject to axial displacement of which the amplitude is variable and is a function of the tilt of the first part (10), making it possible to vary the pitch of the blade during the rotation of same.

Abstract: Turbomachine blade incidence control system including a fluidic cylinder with a first and a second chamber and having a pressurized fluid network adapted to selectively supply pressurized fluid to the first and/or the second chamber, the fluid network having one fluid routing device having a first normal position and a second protection position. The fluidic cylinder includes a fluid inlet positioned to be in fluid communication with the first chamber when the fluidic cylinder is in the blocked position, the routing device being adapted to set up a fluid communication between the inlet and the second chamber when it is in the protection position and to inhibit the fluid supply to the inlet when it is in the normal position.

Abstract: A hydraulic control valve (10) provided with at least one body (11) having a jacket (12) with a feed orifice (13). The hydraulic control valve (10) has a transfer rod (15) provided with at least one fluid transfer duct (16), at least one orifice (17) present inside the jacket (12), and a second orifice (18) arranged outside the jacket (12). The jacket (12) has a feed chamber (25) connected to said feed orifice (13) and a main fluid-return chamber (30) connected to discharge means (50) for discharging the fluid, control means (20) being secured to the jacket (12) in order to move the jacket (12) in translation relative to said transfer rod (15) so as to control the flow of fluid within said transfer rod (15).

Abstract: A turbomachine including at least one unducted propeller with variable pitch blades, the blades being carried by respective plates mounted to pivot in radial housings of a rotor element and connected to a control ring that is driven in rotation about the axis of the turbomachine together with the rotor element, and that is movable in translation along the axis to pivot the plates about their axes, the control ring being centered and guided in rotation about the axis on a mechanism that is stationary in rotation and movable in translation along the axis by an actuator carried by the stator of the turbomachine.

Abstract: According to one embodiment, a radial fluid device comprises a cylinder block, first and second pluralities of pistons, a first cam disposed about the first plurality of radially extending cylinders, and a second cam disposed about the second plurality of radially extending cylinders. The second cam has at least one more lobe than the first cam.

Abstract: A pitch control mechanism is provided for angular displacement of propellers of a propeller assembly of an engine arrangement. The pitch control mechanism has an epicyclic gear system rotating with the propeller assembly. The pitch control mechanism further has a drive gear controlling the rotational speed of the first epicyclic input in the rotating frame of reference of the propeller assembly, a control gear controlling the rotational speed of the second epicyclic input in the rotating frame of reference of the propeller assembly, and a drive mechanism rotating with the propeller assembly. The drive mechanism accepts rotary motion from the epicyclic output to deliver an output motion which angularly displaces the propellers of the propeller assembly.

Abstract: A back-up featherer is provided for an engine arrangement. The engine arrangement has a main hydraulic actuator which operates a pitch change mechanism to angularly displace propellers of a propeller assembly of the engine arrangement, the pitch change mechanism and main hydraulic actuator rotating with the propeller assembly. The back-up featherer has one or more brakes located on a static structure of the engine arrangement. The back-up featherer further has one or more input gears rotatable about respective axes, which axes rotate with the propeller assembly. The input gears are operatively connected to the brakes such that, when the brakes are activated, the input gears rotate about their axes.

Abstract: An upwind wind turbine includes a tilting coupling mechanism configured to couple base end portions of blades to a hub such that the blades can tilt between a normal position and a retracted position in which the blades are tilted in a downwind direction relative to the normal position. The upwind wind turbine also includes a tilting drive operating in association with the tilting coupling mechanism to switch the positions of the blades and a rotation stop to stop the rotation of the rotor. When the blades are switched to the retracted position, the rotation stop is actuated to stop the rotor in a predetermined rotational position in which the blades can tilt without interference with the tower, and the tilting drive is actuated to tilt the blades to the retracted position after stop of the rotation of the rotor.

Abstract: The present invention relates to a method of reducing the vibration of a lift and propulsion rotor (5) of a rotorcraft (1), the rotor having a plurality of airfoil assemblies (10) that perform rotary movement around a drive axis (AX) of the rotor (5), each airfoil assembly (10) comprising a blade (20) extending longitudinally from a root (22) suitable for being fastened to hinge means (4) of a hub (6) of said rotor (5) to a free end (21), a first distance (D1) extending between said free end (21) and said hinge means (4). In the method, said first distance (D1) is caused to vary cyclically so that the projection (TR) of the center of gravity (Cg) of a blade (20) on a horizontal plane (P) perpendicular to said drive axis (AX) and containing said hinge means (4) describes a circle.

Abstract: A wind turbine generator generates power through rotation of a rotor to which a plurality of blades are pivotally coupled and includes a pitch-angle control section that outputs a pitch-angle command value that indicates the amount of change in the pitch angle of each of the blades, hydraulic cylinders each of which changes the pitch angle of the corresponding blade based on the corresponding pitch-angle command value output from the pitch-angle control section, and load measurement sections that measure blade-root loads. A set value indicating that wind received by the wind turbine generator has a biased wind speed distribution is set in advance in the pitch-angle control section. Only when a calculated pitch-angle command value exceeds the set value, the pitch-angle control section outputs a pitch-angle command value beyond pitch command limit values.

Abstract: Proposed is a redundant hydraulically controlled variable pitch propeller for an air, land or water craft, comprising at least two propeller blades (14) mounted in a propeller hub (12) for variable pitch control by means of a hydraulically powered piston assembly (18). In accordance with the invention the piston assembly (18) comprises two mechanically interconnected servo pistons (20, 22) each assigned an independent hydraulic circuit.

Abstract: A hydraulic cylinder is coupled to blades of a wind turbine generator and actuated to change a pitch angle of the blade. A variable displacement hydraulic pump supplies hydraulic oil to the hydraulic cylinder, and a discharge pressure of the pump does not follow a load pressure. When the discharge pressure of the hydraulic pump becomes a set pressure, a pressure control valve is opened to change a discharge amount of the hydraulic pump, and to make the discharge pressure of the hydraulic pump to be a pressure smaller than a cut off pressure. Further, a setting control unit sets the set pressure based on the hydraulic pressure that the hydraulic cylinder requires such that the set pressure becomes a minimum pressure required to change the pitch angle to a predetermined angle by the hydraulic cylinder.

Abstract: A pitch-control system according to the present invention includes a cylinder support portion provided on a rotor hub, a support point thereof being located away from a front end face (unsupported end) of the rotor hub on the opposite side of the rotor hub; a decentered coupling point provided at a decentered location on a root-side end face of the wind turbine blade; and a cylinder that is installed so as to pass through the unsupported end of the rotor hub, a coupling portion that is provided on a portion that protrudes to the outer side from the unsupported end being coupled in a freely rotatable manner to the support point via a spherical joint, and a coupling portion that is on the inner side of the unsupported end being coupled in a freely rotatable manner to the decentered coupling point via a spherical joint.

Abstract: A hydraulic valve assembly includes a hydraulic valve, a control rod configured to be moved in translation along a first longitudinal axis by flight controls of an aircraft, a servocontrol, and an outlet rod configured to be moved in translation along a second longitudinal axis and configured to transfer a hydraulic fluid between the servocontrol and the hydraulic valve. A blocker device is configured to block a movement of the control rod when a difference between a first movement of the control rod and a second movement of the outlet rod exceeds a predetermined threshold and includes at least one moveable abutment configured to block the movement of the control rod when the predetermined threshold is reached and configured to move in longitudinal translation with the outlet rod, and a differential lever configured to mechanically link the control rod to the outlet rod and to cooperate with the at least one moveable abutment.

Abstract: Spaced apart counter-rotatable forward and aft rows of forward and aft propellers are mounted on forward and aft rotatable frames. Hydraulic rotary forward and aft pitch change actuators on the frames are operable for controlling pitch of the propellers. A hydraulic fluid supply outboard of the frames is connected to forward and aft rotary unions which are operable for transferring hydraulic fluid between forward and aft union stators to forward and aft union rotors mounted within the forward and aft rotary unions. The forward union rotor is operable to transfer the hydraulic fluid from the forward rotary union to the aft pitch change actuators and the aft union rotor is operable to transfer the hydraulic fluid from the aft rotary unions to the forward pitch change actuators. The forward and aft rotatable frames counter-rotatably mounted on a structural frame located forward or aft of the propellers.

Abstract: A blade pitch driving apparatus of a wind-driven generator and a driving method therefor are adapted to receive an external electrical power and impel a blade toward a corresponding pitch angle according to a pitch command. The apparatus includes an UPS, a permanent magnet synchronous motor drive (PMSM drive), an AC pitch motor (ACPM) and a hub controller. The hub controller normally switches the external power to the PMSM drive, receives the pitch command and control the ACPM to impel the blade toward the corresponding pitch angle. When the PMSM drive fails or the external electrical power is interrupted, the hub controller switches the electrical power of the UPS to the ACPM and controls the blade being impelled toward a feathered position.

Abstract: An actuation system includes a pump assembly configured to form a pump chamber, an actuator having first and second chambers and a movable member and configured to convert pressures applied to the first and second chambers into a movement of the movable member, and a valve section. The valve section has a plurality of positions set by a controller, and the plurality of positions includes a first position in which the valve section opens the first flow path and closes the second flow path, a second position in which the valve section closes the first flow path and opens the second flow path, and a neutral position in which the valve section closes the first and second flow paths.

Abstract: A wind turbine includes at least one wind turbine blade assembly. The blade assembly includes a blade and a pitch bearing arranged between the blade and a hub of the wind turbine, the blade assembly further including two or more hydraulic pitch cylinders for pitching the blade in relation to the hub. The two or more hydraulic pitch cylinders are arranged to expand in the same angular direction around the rotational axis of the pitch bearing. A method for pitching a blade of a wind turbine includes connecting a first end of the hydraulic pitch cylinders directly or indirectly to the hub; connecting a second end of the hydraulic pitch cylinders directly or indirectly to the blade; and expanding or contracting the hydraulic pitch cylinders in the same angular direction in relation to the rotational axis of the pitch bearing.

Abstract: The invention relates to a rotational device that is to be used in a fluid in order to generate power from the moving stream of a fluid or to convert energy into a motion of a fluid. Said rotational device comprises main rotating means which is fixedly connected to a central rotary shaft of the rotational device, one or several rotational surfaces which are mounted on the main rotating means so as to be rotatable about rotational surface rotary shafts spaced away from the rotary shaft such that the main rotating means are able to perform a rotational motion about the central rotary shaft by means of at least one rotational surface, the rotational surface rotary shafts extending parallel to the rotary shaft of the main body. A device is provided which adjusts an angle of the rotational surface relative to the direction of flow of the fluid in such way that the buoyancy principle is maintained on the rotational surface.

Abstract: A device is provided for the adjustment of the pitch of a rotor blade of a wind turbine. The device includes a pitch actuator and a fixing device. The pitch actuator includes a tube. The fixing device includes a first and a second ring-like element, each of which is arranged at the tube and each of which is supported towards a respective stopper assigned to the tube, and a clamping means which press the first and the second ring-like element in such a way towards the respective stopper that the fixing device and the tube are substantially non-relocatable relatively to each other.

Abstract: A pitch-control system according to the present invention includes a cylinder support portion provided on a rotor hub, a support point thereof being located away from a front end face (unsupported end) of the rotor hub on the opposite side of the rotor hub; a decentered coupling point provided at a decentered location on a root-side end face of the wind turbine blade; and a cylinder that is installed so as to pass through the unsupported end of the rotor hub, a coupling portion that is provided on a portion that protrudes to the outer side from the unsupported end being coupled in a freely rotatable manner to the support point via a spherical joint, and a coupling portion that is on the inner side of the unsupported and being coupled in a freely rotatable manner to the decentered coupling point via a spherical joint.

Abstract: A propeller system includes a propeller hub which supports a multiple of propeller blades. A tailshaft extends from a propeller hub portion of the propeller hub along an axis of rotation with a propeller pitch change yoke mounted within the propeller hub for movement along an axis of rotation to change a pitch of the multiple of propeller blades, the propeller pitch change yoke in sliding engagement with the tailshaft.

Abstract: A device is provided for the adjustment of the pitch of a rotor blade of a wind turbine comprising a pitch actuator acting on an adjusting plane for the adjustment of the pitch and a fixing device to which the pitch actuator is attached, the fixing device comprises a first and a second bearing shaft allowing a pendulum motion of the pitch actuator wherein both the first and the second bearing shaft are arranged respectively under a certain tilt angle relatively to the adjusting plane which tilt angle is respectively substantially different from 0° or 90°.

Abstract: Provided are a pitch actuator for a wind turbine generator and a wind turbine generator that can be prevented from losing their reliability. Provided are a cylinder (12) and a rod (13) that rotate a wind turbine rotor blade about an axis thereof relative to a rotor head to change a pitch angle; a cylinder bearing (14, 15) supporting the cylinder (12) so as to be rotatable relative to the rotor head about a first rotation axis (L1) extending substantially parallel to the axis of the wind turbine rotor blade and about a second rotation axis (L2) extending in a direction crossing both the first rotation axis (L1) and the axis of the cylinder (12) and the rod (13); and a rod bearing (16) rotatably supporting an end of the rod (13) on an end surface of the wind turbine rotor blade.

Abstract: A device for measuring the displacement travel of a hydraulic displacement mechanism for blades of an impeller of an axial-flow fan, wherein the displacement mechanism includes as components a displacement cylinder and a piston rod having a piston, one of the components being axially displaceable and the other component not being axially displaceable. Respective spindles of the blades are secured to a displacement disk to which is connected the axially displaceable component of the displacement mechanism. An oil transfer element surrounds an extension of the piston rod that extends out of the displacement cylinder. A magnetostrictive displacement-measuring device that includes a sensor housing with a wave guide, sensor head, and an annular magnet is coupled to the displacement mechanism. The sensor housing and the sensor head are connected to the oil transfer element. Either the oil transfer element or one of the displacement mechanism components is axially displaceable relative to the other component.

Abstract: The present invention provides an improvement for use in a wind turbine (20) having a plurality of variable-pitch blades (24) mounted on a hub (23) for rotation relative to a nacelle (22). The improvement broadly includes: a electro-hydraulic actuator (25) for controlling the pitch of one of the blades, the actuator including: a motor (26) adapted to be supplied with a current; a pump (27) driven by the motor and arranged to provide a hydraulic output as a function of the current supplied to the motor; and a hydraulic actuator (28) operatively arranged to selectively vary the pitch of the associated blade as a function of the hydraulic output of the pump; and wherein the motor, pump and actuator are physically arranged within the hub of the wind turbine.

Abstract: A engine such as a gas turbine engine has a bladed rotor 24 having variable pitch blades 8. In normal operation, the pitch angle of the blades 8 is controlled by a primary pitch control system. A back-up system is provided for controlling the blades 8, for example to displace them to a feathered condition, in the event of failure of the primary pitch control system. The back-up system comprises a pump 32 mounted on the rotor 24, and driven by relative rotation between the rotor 24 and a contra-rotating rotor 23. In response to a failure signal on a conduit 48, the pump delivers hydraulic fluid under pressure to a secondary actuator 30, which acts on the blade 8.

Abstract: The invention relates to a wind turbine having rotating means including at least two wind turbine blades which are turnable around the longitudinal axis of said blades, and a wind turbine hub connecting said at least two wind turbine blades with at least one shaft. Further, the wind turbine includes hydraulic means for actuating said at least two wind turbine blades, said hydraulic means being incorporated in said rotating means. The invention also relates to a hydraulic system, an air bleed system and a method of controlling at least two wind turbine blades.

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: Proposed is a redundant hydraulically controlled variable pitch propeller for an air, land or water craft, comprising at least two propeller blades (14) mounted in a propeller hub (12) for variable pitch control by means of a hydraulically powered piston assembly (18). In accordance with the invention the piston assembly (18) comprises two mechanically interconnected servo pistons (20, 22) each assigned an independent hydraulic circuit.

Abstract: A wind turbine with improved response to wind conditions is provided. Blade flap angle motion is accompanied by a change in pitch angle by an amount defining a pitch/flap coupling ratio. The coupling ratio is non-constant as a function of a flap angle and is preferably a substantially continuous, non-linear function of flap angle. The non-constant coupling ratio can be provided by mechanical systems such as a series of linkages or by configuring electronic or other control systems and/or angle sensors. A link with a movable proximal end advantageously is part of the mechanical system. The system can provide relatively large coupling ratios and relatively large rates of coupling ratio changes especially for near-feather pitches and low flap angles.

Abstract: A device is provided for the adjustment of the pitch of a rotor blade of a wind turbine comprising a pitch actuator acting on an adjusting plane for the adjustment of the pitch and a fixing device to which the pitch actuator is attached, the fixing device comprises a first and a second bearing shaft allowing a pendulum motion of the pitch actuator wherein both the first and the second bearing shaft are arranged respectively under a certain tilt angle relatively to the adjusting plane which tilt angle is respectively substantially different from 0° or 90°.

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: The hub for the rotor (22) of a wind energy turbine (10) comprises a hollow body (28) rotatable around a rotation axis and provided with at least one flange (34) for mounting to the hollow body (28) a bearing for a rotor blade (26) and at least two stiffening webs (38) integrally formed with the hollow body (28) and radially extending within a flange area (36) of the hollow body (28) surrounded by the flange (34) to the center (40) of the flange area (36), wherein at least two openings are provided within the flange area (36) of the hollow body (28).

Abstract: An electronic control device for opening and closing valves in a valve assembly that actuates a variable pitch fan system capable of operating in a plurality of fan blade pitch positions including a temperature switch actuated in response to a temperature condition of the engine, a pressure switch in series with the temperature switch and actuated in response to a pressure condition of the variable pitch fan system, and a time delay relay control in parallel with the temperature switch and the pressure switch for transmitting a timed signal therefrom. The device also includes a first solenoid in series with the pressure switch, a second solenoid in series with the time delay relay control and connected to the first solenoid, and wherein transmission of at least one of the timed signal, the temperature condition signal, and the pressure condition signal opens or closes the valves of the valve assembly of the variable pitch fan system.

Abstract: A variable pitch fan in which the pitch of the fan blades is varied under control of a controller according to the speed of the fan. The controller is programmed to respond to increased fan speed by decreasing pitch of the fan blades. The variable pitch fan has a piston extending axially from a main shaft, about which main shaft a fan blade hub rotates. A pitch shifter is mounted on a cylinder, which itself is mounted on the piston. The pitch shifter is actuated by hydraulic fluid supplied through the main shaft to the cylinder. The piston is preferably axially stationary in relation to the main shaft. The cylinder is secured against rotational movement by cooperating out of round surfaces. Grease for the pitch shifter is supplied through the guide pin. One guide pin may be used for grease supply, while another may be used for excess grease return.

Abstract: An individual blade adjustment system for wind turbines comprising two drive units which are joined to at least one movable rocker arm, substantially in the cutting plane of the blade connection and which forms a lever mechanism together with the rocker arm, wherein each drive unit produces a linear extension. The respective ends of the lever mechanism are provided with a force-transmitting link to the hub and an element on the blade to be adjusted through each pivot connection.

Abstract: The expense of a bearing employed at the interface of a yoke (22) and a propeller blade pin (14) in a variable pitch propeller assembly is reduced in a bearing construction (16) wherein a bearing race (48) includes a crowned surface (50) adapted to engage a slot (20) in the yoke (22) and having a profile (P1) wherein the diameter at one side (88, 90) of the race (48) is less than the diameter at the opposite side (90, 88) of the race (48).

Abstract: Helicopter blades each have a piston connected to it. The pistons are movable within a cylinder between innermost and outermost positions. The hydraulic fluid of each cylinder is connected to other cylinders by a hydraulic tube or through a manifold. A drive bar moving synchronously with the blades is connects to the cylinders. As the helicopter moves in flight the force of the wind against a blade causes a piston to move inwardly. This causes fluid to be expelled from the cylinder into the another cylinder by way of the hydraulic tube causing other piston to be moved outwardly. Meanwhile the other piston, because it is moving with the wind, is exerting an opposite effect on the other piston. The result is a tendency for the blades to approach an equilibrium condition with respect to the wind forces to minimize the shocks to the overall system.

Abstract: A pressure relief device for preventing over pressurization of a propeller hub is disclosed. The pressure relief device is designed to fit within a ball hole opening in the hub arm of the hub. The pressure relief device includes a housing which sealably interfaces with an inner wall of the ball loading hole opening and a diaphragm which sealably interfaces with the housing. The diaphragm is designed to rupture at a design pressure thus venting the hub cavity.

Abstract: The invention provides for a cycloidal propeller, in strictly rudder operation, accessory apparatuses that mesh with a gear drive connected to a shaft of the respective wing. The invention accomplishes relatively small actuation movements of the accessory apparatuses, sufficient to achieve a large pivoting movement of the wings, so that the wings can be adjusted over large angles without impediment. Therefore, wings having normal profiles may be utilized.

Abstract: A cycloidal propeller to achieve strictly a rudder operation includes accessory apparatuses containing accessory drives. Clutches are used to couple the accessory drives to the propeller shafts, and additional clutches are provided to disengage the fixed connection of the normal propeller mechanism to the wing shafts in cruising operation.

Abstract: A wine turbine with blades having a high lift-to-drag ratio is provided. A hydraulic or other control system is used to control cone angle, such as in response to flap moment. Pitch of blades is controlled, such as in relation to the blade flap angle. Teeter motion is controlled preferably as a function of teeter angular velocity.

Abstract: The hub for the rotor (22) of a wind energy turbine (10) comprises a hollow body (28) rotatable around a rotation axis and provided with at least one flange (34) for mounting to the hollow body (28) a bearing for a rotor blade (26) and at least two stiffening webs (38) integrally formed with the hollow body (28) and radially extending within a flange area (36) of the hollow body (28) surrounded by the flange (34) to the center (40) of the flange area (36), wherein at least two openings are provided within the flange area (36) of the hollow body (28).