Abstract: One example includes a passive rotor pitch control system. The system includes a counterweights that are each associated with one of a respective plurality of rotors and can be arranged to have a center of mass configured to provide a pitch torque about a pitch axis associated with the respective one of the rotors in response to rotation of the rotors about a rotation axis. The system also includes a spring forcer comprising a pitch rod and a spring configured to provide a spring force on the pitch rod. The system further includes a pitch change assembly coupled to the counterweights and the pitch rod. The pitch change assembly can be configured to rotate a pitch of each of the rotors from a first pitch state to a second pitch state in response to a sum of pitch torques associated with the counterweights being greater than the spring force.

Abstract: There is described herein the automation of propeller feather testing functions, whereby the test is automatically performed and a pass/fail signal is issued upon completion.

Abstract: A method (600) for testing control logic for a propeller driven by a gas turbine engine of an aircraft includes overriding (602) a signal indicating the aircraft is operating in a ground mode. The method can further include testing (604) minimum pitch protection logic when the signal is overridden; determining (606) the gas turbine engine is operating at a ground fine setting; restoring (608) the signal to an original state in which the signal indicates the aircraft is operating in the ground mode; modifying (610) pitch protection logic; determining (614) the propeller is operating at an overspeed condition; and testing (616) the propeller overspeed protection logic. In addition, the method can also determine (612) the propeller is operating at a low pitch condition when the gas turbine engine is operating at the ground fine setting.

Abstract: Methods and systems for setting a target power of an aircraft engine are described herein. A power lever position is obtained. At least one flight condition indicative of a phase of flight of the aircraft is obtained. A maximum rated power of the engine is determined for one or more engine rating based on the phase of flight. The target power of the engine is set based on the power lever position and the maximum rated power of the one or more engine ratings.

Abstract: A pitch varying device, a pitch varying method and a pitch varying control device for a wind turbine blade and a wind turbine are provided. The blade pitch varying device includes: a disc-type driving structure perpendicular to an axis of a pitch bearing, a track surrounding the axis of the pitch bearing being provided on the disc-type driving structure; a first linear telescopic driving mechanism connected to the track through a first clamping member capable of clamping the track, and the first linear telescopic driving mechanism and the first clamping member being connected through a hinge connection; and a second linear telescopic driving mechanism connected to the track through a second clamping member capable of clamping the track, and the second linear telescopic driving mechanism and the second clamping member being connected through a hinge connection.

Abstract: A helicopter includes a rotor system having a rotor with an adjustable pitch that is controlled at least in part by a pilot using a collective control and which helicopter generates a Low RPM signal that is indicative of a threshold low rotational speed of the rotor. An actuator arrangement can move the collective control by exerting a force on the collective control such that the pilot is able to overcome the actuator force but which otherwise can move the collective control from a current operational position toward a minimum pitch position. A clutch can co-rotate with a motor to serve in transferring the actuation force to reduce the adjustable pitch and can slip relative to the actuator shaft assembly responsive to an application of a counterforce applied by the pilot to the collective control such that the counterforce overcomes the actuation force.

Abstract: A method for creating a tapered spiral welded conical structure where the overall shape of the cone is first graphically slit axially and unwrapped, and then a series of construction arcs and lines are created to form the edge lines of a strip that can then be wrapped (rolled) to form a tapered conical structure. The edges of the spirally wound strip can be welded together, and a very large conical structure can thus be achieved. Various construction options are presented from a constant width strip to strip made from straight segments. Equations are given for the formation of the strips to enable those skilled in the art of spiral welded tubing to practice the invention.

Abstract: A propeller control system includes a propeller control logic subsystem in conjunction with an engine control logic subsystem to provide an optimized transition from forward to reverse speed governing under all operating conditions. By creating a Propeller control Mode (PCM) map relative the blade angle and Power Lever Angle (PLA), the minimum blade angle allowed for forward speed governing and the maximum blade angle allowed for reverse speed governing is determined. By combining the actual propeller blade angle, the min and max angles for speed governing, and the PLA signal, the state of the propeller speed governor is determined.

Abstract: The present invention relates to a control and regulation method for a rotorcraft having at least one variable-pitch propulsive propeller driven by at least one power source, said method consisting in generating at least one mean pitch setpoint ?tcl* for the propeller(s) as a function of a thrust variation control order Tcl, wherein the method consists in defining a plurality of operating modes, including: a direct mode in which the value of the mean pitch value is a direct result of the control order Tcl; a forced mode in which the mean pitch is automatically forced to a calculated pitch value; a regulated mode in which the power of the propulsive propeller(s) is regulated as a function of a power setpoint from a pilot and of servo-controlling the mean pitch of the propeller(s); and a protected mode.

Abstract: A helicopter includes a rotor system having a rotor with an adjustable pitch that is controlled at least in part by a pilot using a collective control and which helicopter generates a Low RPM signal that is indicative of a threshold low rotational speed of the rotor. An actuator arrangement configured to move the collective control by exerting a force on the collective control such that the pilot is able to overcome the force but which otherwise moves the collective control from a current operational position toward a minimum pitch position. A control arrangement is configured for receiving the Low RPM signal and for responding to the Low RPM signal by activating the actuator arrangement for at least a predetermined period of time to apply the force to move the collective control from the current operational position to the minimum pitch position.

Abstract: A control system for mitigating the effects of a wind turbine on a radar system is disclosed. The control system includes a sensor configured to detect an operating condition of the radar system; a processor configured to receive an operating condition of the wind turbine and determine a rotation modification sequence based on the operating condition of the radar system and the operating condition of the wind turbine; and a controller configured to apply the rotation modification sequence to the wind turbine. A method of mitigating the effects of a wind turbine on a radar system is also disclosed.

Abstract: A brake system for a ram air turbine (RAT) causes the RAT to slow or lock if the RAT achieves an over-speed condition with a centrifugal force operated trigger system that actuates a compression type brake pack to slow or lock the turbine hub.

Abstract: An electronic self-powered propeller governor driven off the aircraft engine includes a drive shaft which drives a hydraulic pump to produce pressurized oil to move a hydraulically controlled piston connected to the propeller blade for changing the blade pitch. A hydraulic control valve which controls the position of the piston includes a spool which is positioned within the drive shaft and supplies pressure to the piston for changing the pitch of the propeller blade. The drive shaft also drives an AC generator producing an electrical RPM signal which is supplied to a linear control circuit. A manually operated RPM control produces an electrical signal supplied to said linear control circuit which is compared with the RPM signal produced by the generator and in turn the linear control circuit signals an actuator.

Abstract: An improved electronic hydraulic propeller control designed as a retro-fit kit for existing Hamilton Standard Division 54460 and 54H60 propeller controllers includes an apparatus for controlling the pitch angle of a propeller blade. The retro-fit kit includes an electro-hydraulic servo valve, an electronic controller, a protection valve, and a propeller maintenance interface panel. These components functionally replace the existing hydromechanical propeller control system without reconfiguration of the existing interface. The apparatus converts mechanical inputs of the propeller and airframe systems to electronic signals, which can be measured by the electronic control. The apparatus also receives and converts the electronic control's commands into hydraulic pressure and flow changes through an electro-hydraulic servo valve. The electronic controller performs the required calculations to interpret and then react to changes in the propeller/airframe systems.

Abstract: A system for controlling functions of a propeller having a plurality of blades is disclosed. The system comprises an electronic control for controlling the functions of the propeller. A plurality of backup devices are provided for backing up the electronic control upon the occurrence of conditions. These conditions include at least one of testing, manual override, and a malfunction in the electronic control causing at least one of the functions to endanger safety. The system further includes a bypass device for bypassing the electronic control and for invoking at least one of the plurality of backup devices to acquire control over at least one of the functions. The bypass devices include a mechanism for determining the occurrence of at least one of the conditions and for actuating electronic control override.

Abstract: An air driven turbine having variable pitched blades is provided that includes a pitch change mechanism and associated control circuits for automatically adjusting the pitch of the blades during either rotating or non-rotating operational modes of the air driven turbine. The pitch control mechanism includes a resettable overspeed protection device which is directly actuated by an overspeed condition of the turbine and operates independently from the pitch change mechanism to move the blades to a failsafe, feathered, or coarse pitch, low speed position. The pitch control mechanism utilizes a linear actuator in the form of an acme screw drive. The air driven turbine includes a ball ramp thrust bearing for attaching the blades to a hub of the turbine in such a manner that during rotation of the turbine actuation loads on the pitch change mechanism are reduced.

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 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 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: 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: A counterrotatable bladed rotor assembly drivable by a rotatable shaft comprises a leading propeller, a trailing propeller, and a gearbox located axially between the two propellers and enclosed by a non-rotatable casing having an end for attachment to a support structure. The gearbox has a first output shaft to the leading propeller and a second output shaft to the trailing propeller. A first fluid-pressure operable actuator is provided to vary the pitch of the blades of the leading propeller, and a second fluid-pressure operable actuator is provided to vary the pitch of the blades of the trailing propeller. In addition passageways are provided to connect the first and second actuators to a source of fluid under pressure. The casing rotatably supports the second output shaft at a position between the gearbox and the leading propeller and rotatably supports the first output shaft at a position between the gearbox and the trailing propeller.

Abstract: A windmill generally intended to rotate in a horizontal plane about a vertical axis, includes essentially radial vanes; each which is effectively a one way valve respective to air flow; each which can enhance (or supplement) the beneficial actions of the others; and each of which vanes, in operation, effectively simulates a sailing vessel navigating a circular course in wind of constant direction. Each of said vanes includes a framework which supports a grid, which grid is the supporting means for a plurality of pivotally connected vertically aligned and overlapping light weight flexible sails, which sails are automatically rotated about said pivotal connection by the force of the wind into positions promoting the revolution of the windmill. Included with said sails are various devices as spars, springs and cords which promote and enhance their efficient automatic operation. The windmill is inherently self protecting in high winds and self regulating in speed of rotation.

Abstract: Apparatus is for controlling load on an engine, particularly a marine engine powering a controllable pitch propeller which serves as an engine loading device. Apparatus cooperates with a circuit having a supply fluid at a constant supply pressure, and a control fluid at a variable control pressure reflecting engine load. The apparatus has a signal receiver to receive a load demand signal from an operator, and a positioner apparatus with a positioner output which cooperates with the loading device of the engine. The positioner apparatus receives the supply and control fluids and has a partition separating the fluids to permit interaction therebetween to control the positioner output. The apparatus has a hydraulic fluid valve to control flow of hydraulic fluid relative to the positioner apparatus, the fluid valve being connected to the positioner output and an output of the signal receiver so as to be responsive to relative positions of both outputs.

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 pitch control system (10) for a variable pitch propeller effects engine governor (330), control of blade pitch under normal operating conditions and automatically effects direct (beta) control of blade pitch by the power lever (305) throughout a predetermined range of power lever settings. The system is hydromechanical and comprises a pitch actuator (40) and a pair of control valves (120 and 210), a first of the valves (120) applying a metered fluid pressure from a governor controlled pilot valve to the actuator and blocking that signal and replacing it with a supply fluid pressure at the point of transition from governor to beta control. The second control valve (210) effects a controlled draining of the actuator and connection thereof with the power lever (305).

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: 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: Apparatus including series-connected pitch inching pilot valve, load control pilot valve, pressure feedback valve assembly, pitch direction selector valve, and servo power cylinder assembly. A load control bypass valve is connected in parallel with the pressure feedback valve assembly and a pitch reduction damping check valve is connected in parallel with the load control pilot valve. Counterbalancing pilot signals in the pitch inching pilot valve are received from a pressure varying manual control valve and a pitch feedback transmitter; in the load control pilot valve either from a manual load control valve and a governor load feedback valve or from each side of the pressure feedback valve assembly; in the load control bypass valve from the outlets of the inching pilot valve and the load control pilot valve.

Abstract: A controllable pitch marine propeller has blades carried by a hub and a hydraulic actuator housed in the hub and coupled to the blades for altering the pitch angle of the blades in both directions, astern and ahead, and also beyond the ahead position to a feathered position. A servo-control system controls the actuator to adjust the blade pitch angle, the control system having a blade position feedback loop by which the system operates with positional feedback over the range of pitch angle between astern and full ahead pitch angles. However, the demand signal for blade feathering renders the feedback loop inoperative, and the hydraulic actuator then moves the blades into the feathering position without feedback action.