Abstract: An aircraft propeller has adjustable pitch blades which are reset from a low pitch in-flight idle position to a lower pitch ground idle position by a beta feedback and reset mechanism. The reset mechanism includes a set of cam elements supported for movement in response to rotation of the blades and positioned to engage a follower plate adjustably mounted on the beta feedback control rods.

Abstract: An overspeed protection system for an aircraft fan engine wherein blades are rotatable from a coarse pitch to a fine pitch to a thrust-reverse condition. A wobbler-type hydraulic motor is provided for rotating the blade. An overspeed governor is operatively associated with the motor for effecting rotation of the blades in a direction toward the coarse pitch condition. A control, including a solenoid valve actuatable in thrust-reverse mode, changes the sense of the hydraulic motor to drive the motor further into thrust-reverse on actuation of the overspeed governor means.

Abstract: A cam mechanism enabling the pilot to automatically advance the propeller low pitch stop with the engine power lever on airplanes with multibladed propeller systems having a beta control mechanism for adjusting the blade angle. The cam provides an inexpensive and reliable alternative to costly and complex automatic feathering systems.

Abstract: An aircraft propeller has adjustable pitch blades which are reset from a low pitch in-flight idle position to a lower pitch ground idle position by a beta feedback and reset mechanism. The reset mechanism includes a set of cam elements supported for movement in response to rotation of the blades and positioned to engage a follower plate adjustably mounted on the beta feedback control rods.

Abstract: Hydraulic fluid is input to a transfer tube of a variable pitch propeller system forward of a rotatable portion of a controller. A transfer bearing is provided about the drive shaft to transfer hydraulic fluid therethrough and between the drive shaft and the transfer tube to transfer hydraulic fluid from the drive shaft into the transfer tube, such transfer bearing allowing relative rotation between the housing and the drive shaft and between the drive shaft and the transfer tube. The transfer tube is slideably connected to the rotatable portion of the controller.

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: A bladed rotor assembly and a control means therefor, which comprises a bladed rotor, a fluid-pressure-operable actuator for effecting a change of blade pitch, a first valve member connect to, and movable with the actuator and a second valve member co-operable with the first valve member, both valve mebmers having fluid passageways therein for supplying fluid to the actuator, and override means being provided to control the position of the second valve member relative to the first valve member, wherein safety means are provided to cause, in the event of failure of the over-ride means, the actuator to effect increased blade pitch.

Abstract: An actuating system for a controllable pitch propeller comprises a hydraulic servomotor arranged in the propeller hub and being connected mechanically to the propeller blades. Pressure medium is delivered to the servomotor, under the control of a control valve, from a pressure-medium source, which is connected to a stationary pressure-medium chamber which embraces a rotatable shaft connected to the propeller and which is sealed against the outer surface of the shaft and communicates, via a radial pressure-medium channel in the shaft, with an axial pressure-medium channel located in the shaft and extending to the hydraulic servomotor. The system further comprises an additional stationary pressure-medium chamber which embraces the shaft and seals against the outer surface thereof and which, via an additional radial pressure-medium channel in the shaft communicates with the axial pressure-medium channel in the shaft.

Abstract: A master controller 14 on the stationary side of a propeller system 10 sends pitch control signals via a communications link 34 which comprises a pair of capacitors 64, 66, each capacitor having a stationary plate and a rotating plate, one capacitor forming a high potential signal path, the other capacitor forming a low potential return path, across a rotating gap to a slave controller 54 on the rotating side of the propeller system which sets blade pitch according to the pitch control signals and sends pitch position signals back through the communications link to the master controller.

Abstract: A modular, easily replaceable, pitch actuation system is removably secured within the hub of an aircraft. The modular system houses a driving system which provides a rotational output to set the pitch of propeller blades mounted to the hub, and a pitch changing system that controls the driving system. The driving system includes a high-speed, low-torque hydraulic motor that drives an harmonic drive to amplify the torque of the motor. The pitch changing system includes an actuator which positions a valve that controls the hydraulic motor, and a nulling gear which repositions the valve and acts as a pitch lock.

Abstract: Apparatus and methods for adjusting the pitch of a fluid reactive blade member carried upon a rotor in response to a speed difference between the rotor and a reference speed shaft.

Abstract: Apparatus for controlling the pitch of the blades of a variable pitch, governor controlled, aerial propeller of which the pitch of the blades is variable between a coarse pitch limit and a fine pitch limit to match the torque of its prime mover has holding means (A) to maintain a forward thrust-generating blade pitch angle greater than the fine pitch limit with the prime mover idling as when an aircraft propelled by the propeller is taxi-ing whereby the propeller rotates more slowly, and hence more quietly, than it would otherwise. Preferably the holding means is effective by actuating a lock pitch solenoid valve (21) and an autofeather valve (18).

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: A propeller control system, including a propeller governor, overspeed governor, and a bleed valve, is provided to control the flow of fluid under pressure from a pump to an hydraulically controlled, variable pitch propeller driven by a gas turbine engine. Under normal operating condition, the propeller governor controls the pressure of the fluid supplied to the propeller, adjusting its pitch as needed to maintain constant speed operation. The overspeed governor prevents overspeeding of the propeller and engine in the event that the propeller governor becomes inoperative, and, in the event that both governors become inoperative, the bleed valve prevents sudden increases in fluid pressure, attendant with the failure, from adjusting the pitch of the propeller towards an overspeed position.

Abstract: In a propeller pitch control system, a selector 10 isolates engine (42) speed control in one of two engine governor (175 and 300) systems. The selector is input with fluid pressure signals from a pair of pilot valves (215 and 325), each operated by a corresponding one of the governors. The selector passes the signal of lowest magnitude to an actuator 40 which sets blade pitch in accordance with the magnitude of the signal whereby the governor providing such signal (through its associated pilot valve) controls engine speed independently of the other governor.

Abstract: A propeller engine system with means for generating electric power within a rotatable hub is disclosed. The means include a shaft extending into the hub so that the hub and shaft are differentially rotatable. Magnetic means are fixed to the shaft and winding means are fixed to the hub so that either rotation of the rotor shaft or hub induces an electric current in the winding means.

Abstract: A rotor control system for a helicopter in which the conventional swashplate is eliminated and the rotor hub is integrated to include an actuator for each rotor blade. Two arrangements are employed, each of which utilizes a hydraulic circuit. One arrangement is a hydromechanical arrangement with stick control, while the other arrangement is an electro-hydraulic fly by wire arrangement. The latter does not employ a swashplate, while the former employs a modified swashplate. The controls, like the actuators, are mounted in the rotor hub, and the hydraulic lines and fiber optics pass through the rotor drive shaft to the rotor hub.

Abstract: A blade feathering system for wind turbines includes a feather actuator (299), control means (330 and 335) operatively connected thereto and an adjustment means (340) operatively connected to the control means for selectively varying the rate of operation of the feather actuator for feathering the wind turbine blades (10 and 15) at a variable rate.

Abstract: A pitch control system for a multibladed variable pitch wind turbine. Each of the turbine blades is pivotally driven about the longitudinal axis thereof independently of the other blades by at least a pair of hydraulic actuators. The actuators are supplied with pressurized hydraulic fluid from a first source thereof under conditions of normal pitch change adjustment. Under conditions wherein feathering of the blades is required, the actuators are supplied with hydraulic fluid from second sources thereof such that one of the actuators associated with each of the blades is supplied with fluid from one second source and a second actuator is provided with fluid from a redundant second source whereby blade feathering may be effected despite a malfunction of one of the redundant sources or one of the actuators.

Abstract: Blade pitch actuation system wherein the blades are hydraulically maintained in phase with one another. The system comprises hydraulic actuators each adapted to drive a single blade in a pitch change mode of operation. Fluid flow to the actuators is controlled by a blade actuator control valve in fluid communication with the actuators and an hydraulic fluid source and drain. An input member of the control valve is provided with passages which provide selected communication between the hydraulic fluid source and drain and passages in cooperating control valve feedback members each operated by, and in fluid communication with one of the blade actuators. The input and feedback members are positionable along one another such that selective positioning of the input member causes simultaneous selected pressurization and draining of the blade actuators through the feedback members thereby effecting a desired, phased blade pitch setting.

Abstract: A speed control system for a windmill having blades which can be feathered for altering speed and with the blades under the control of a mechanism which includes a piston assembly and a fluid governor associated therewith. Spring means are used to feather the blades against the force of the piston assembly which is interconnected with the blades, and the speed of blade rotation actually creates the fluid pressure acting on the piston assembly and a governor is associated with the piston assembly for controlling the position of the piston and thus controlling the feathering of the blades, all according to the speed of rotation of the windmill blades. The windmill can be used for generating electric power, and fail-safe mechanisms are employed for protecting in the event of a windmill blade breakage.

Abstract: A mechanism for controlling the pitch of fan blades during rotation of the fan impeller includes a cylinder-piston unit mounted coaxially on the impeller hub, a first conduit arranged to deliver compressed air to one cylinder chamber for axially moving the piston in an operating direction, a normally closed valve in this conduit for preventing compressed air delivery to this chamber, a spring in the other cylinder chamber biasing the piston in an opposite direction, a second conduit arranged to deliver an environmentally controlled flow of compressed air to the valve for opening the valve under predetermined environmental conditions whereby the compressed air in the first conduit is delivered to the one cylinder chamber and moves the piston in the operating direction against the spring bias, and rods connecting rotatable fan blade supports to the piston and causing rotation of the supports about their axes on movement of the piston to control the pitch of the blades.

Abstract: A propeller hub supports a plurality of angularly disposed propeller blades which are movable by a hydraulic cylinder between a high pitch position and a reverse position through a low pitch position. Hydraulic fluid is supplied to the cylinder from a governor unit driven by the aircraft engine, and a fluid pressure responsive relief valve controls the pressure of the hydraulic fluid. The pressure responsive relief valve is manually adjustable by the aircraft pilot to change the fluid pressure at which the valve responds in order to change the pitch of the propeller blades. The fluid pressure must be increased above a predetermined normal operating limit for actuating the cylinder against the bias of a spring within the propeller to move the blades to their reverse pitch position. In addition, a centrifugally actuated lock unit prevents actuation of the cylinder and movement of the blades to their reverse pitch position until the speed of the propeller is reduced to a slow idle.

Abstract: A windmill blade that has a rigid leading edge, a rigid root portion and a movable blade tip. Control of the geometric twist of the windmill blade is accomplished through proper selection of the axis of rotation for the movable blade tip and by controlling the position of the windmill blade tip with a servo motor or by controlling the position of the windmill blade tip with a spring and a weight. The ability to vary the geometric twist of the blade enables the frequency of rotation of the blade to be controlled to reduce wind drags upon the blade. This improved windmill blade eliminates the need for current complicated and expensive rotor hubs which are used to vary the blade pitch angle at the root end of the blade to reduce wind drag upon the blade. Processes related to the windmill blade are also presented.