Abstract: A propeller includes a blade free to rotate. A first stop is positioned to mechanically engage one or both of a first portion of the blade and a first structure coupled to the blade when the blade is in a first position at a first end of the rotational range of motion. A second stop is positioned to mechanically engage one or both of a second portion of the blade and a second structure coupled to the blade when the blade is in a second position at a second end of the defined rotational range. The blade rotates to the first position against the first stop when the propeller is rotated in a first direction and to the second position against the second stop when the propeller is rotated in a second direction.

Abstract: There is described herein methods and systems for testing a propeller feathering function. The method comprises monitoring a rotational speed over time of propeller blades of an aircraft, commanding an angle change of the propeller blades, comparing a post-angle change rotational speed of the propeller blades to an expected rotational speed without the commanded angle change and obtaining, by the processor, a rotational speed difference, and issuing a test passed signal when the rotational speed difference exceeds a threshold and a test failed signal when the rotational speed difference does not exceed the threshold.

Abstract: A passive hub flapping lock including: one or more lever arms, each lever arm rotatably coupled to a pivot and comprising a first lever arm end and a second lever arm end; one or more stop wedges; one or more frames coupled to the one or more stop wedges, each frame coupled to the first lever arm end of one of the one or more lever arms; one or more weight sets, each weight set comprising one or more weights coupled to the second lever arm end of one of the one or more lever arms; and one or more pivot torsion springs, each pivot torsion spring positioned at the pivot.

Abstract: A system for controlling the pitch of fan blades of a turbine engine propeller, the system including an actuator secured to a casing of the turbine engine, having a movable portion that is movable in translation relative to the casing, the movable portion being mechanically coupled to a load transfer bearing having an outer ring that is coupled to fan blade pivots so that a movement in translation of the movable portion of the actuator leads to a change in the pitch angle of the fan blades, and at least one locking peg secured to the casing of the turbine engine and suitable, in the event of the actuator malfunctioning, for mechanically locking the load transfer bearing in a position wherein the fan blades are feathered.

Abstract: There is provided a method for controlling a hydraulic pitch force system (220) so as to reduce or eliminate a decrease in hydraulic oil pressure (241) if a hydraulic system parameter value is outside a hydraulic system parameter range, the method comprising: Obtaining (690) the hydraulic system parameter value, and operating the hydraulic pitch force system (220) according to a reduced mode (692) if the hydraulic system parameter value is outside the hydraulic system parameter range, wherein in the reduced mode one or more pitch based activities are reduced (694) or suspended. An advantage thereof may be that it enables keeping the wind turbine in production in certain instances rather than shutting down the wind turbine. In aspects, there is furthermore presented a computer program product, a pitch control system (250) and a wind turbine (100).

Abstract: A system and method for feathering an aircraft propeller are provided. A first feather solenoid and a second feather solenoid each comprising at least one solenoid coil and a solenoid valve coupled to the actuator and to the at least one solenoid coil are provided. At least one controller is configured to selectively energize and de-energize the at least one solenoid coil. The solenoid valve of the first feather solenoid is configured to be activated when the at least one solenoid coil of the first feather solenoid is energized and the solenoid valve of the second feather solenoid is configured to be activated when the at least one solenoid coil of the second feather solenoid is de-energized. The solenoid valve is configured to, when activated, modulate the supply of hydraulic fluid to an actuator for adjusting a blade pitch of the propeller towards a feather position.

Abstract: A system and method for feathering an aircraft propeller are provided. The aircraft propeller is coupled to an actuator for setting a blade pitch of the propeller. The blade pitch is controlled by modulating a supply of hydraulic fluid to the actuator. At least one feather solenoid is provided that comprises a first solenoid coil, a second solenoid coil, and a solenoid valve coupled to the actuator and to the first and the second solenoid coil. At least one controller is configured to selectively energize and de-energize the first and the second solenoid coil. The solenoid valve is configured to be activated when the first solenoid coil and the second solenoid coil are de-energized and to, when activated, modulate the supply of hydraulic fluid to the actuator for adjusting the blade pitch of the propeller towards a feather position.

Abstract: A method for controlling a wind turbine during a safety operation is disclosed. A safety pitch control system is provided to pitch the blades individually at a number of pre-set approximately constant pitch rates including a first pitch rate and a second pitch rate lower than the first pitch rate. In response to a command for initiating the safety operation the blades are pitched towards a feathering position by the safety pitch control system including the blades being pitched according to a safety pitch strategy wherein for all the blades the pitch rate is changed between the first pitch rate and the second pitch rate according to a function of each blade azimuthal position. This is done such that each blade in turn is closer to the feathering position than the others.

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 propeller pitch control actuation system includes a relatively lightweight, relatively inexpensive means for selectively preventing the propeller pitch control actuator from commanding reverse pitch positions.

Abstract: A propeller rotor has a hub mounting a plurality of blades. A counterweight is movably mounted on the blade. A pitch change mechanism for changing an angle of incidence of an airfoil is associated with each of the blades. The counterweight twists the blades toward an increased pitch direction should the pitch change mechanism fail. A stop member stops rotation of the counterweight as the blade moves to a feather position.

Abstract: The present invention relates to an aircraft gas turbine having a fan rotatable about an engine axis in the inflow region of the aircraft gas turbine, with the fan having several fan blades, with each fan blade being moveably mounted on a hub rotatable about the engine axis by means of its blade root on an area which is at the front in the flow direction, and with each fan blade being moveably mounted on an area at the rear in the flow direction, on an adjusting disk axially displaceable relative to the engine axis and non-rotatable with the hub, with the pitch angle of the fan blades being variable by the axial movement of the adjusting disk.

Abstract: The invention provides a device for controlling the pitch of the fan blades of a turboprop, the device comprising: at least one set of adjustable pitch fan blades, the set being constrained to rotate with a rotary ring mechanically linked to a rotor; a synchronizing ring coupled to each blade of the set in order to adjust its pitch; an actuator centered on the longitudinal axis of the turboprop and constrained to rotate with the rotor; and control links, each connected firstly to the actuator rod and secondly to an inside end of a cylindrical shaft via a crank capable of imparting turning movement to the shaft about its axis of revolution, an outside end of the shaft being coupled to a blade in order to adjust its pitch.

Abstract: The invention relates to a method for operating a wind turbine (10) comprising a rotor (12) and a generator (18), connected to said rotor (12), for outputting electrical power to an electrical grid, said rotor (12) comprising rotor blades (14) whose blade pitch angles (a) may be moved during operation in order to control the rotational speed (n) of the rotor (12). Upon reaching a rotational speed (n) higher than a rotational speed limit (nlim) that delimits an operational range (34, 34?, 34?) of said wind turbine (10), the rotor (12) is forcibly braked by increasing the blade pitch angle (?) at a predefined positive blade pitch angle movement rate (?r), particularly at a maximum potential positive blade pitch blade angle movement rate (?r,max). According to the invention, the rotational speed limit (nlim) is altered as a function of a blade pitch angle movement rate (?) set by the control. The invention also relates to a corresponding wind turbine (10).

Abstract: According to the inventive concept, there is provided a wind turbine with at least one blade. The wind turbine comprises a first accelerometer mounted at a first radial position of the blade and being adapted to determine a first acceleration value, and a second accelerometer mounted at a second radial position of the blade different from the first radial position, and the accelerometer being adapted to determine a second acceleration value. The wind turbine further comprises a controller adapted to generate a signal based on said first and second acceleration values. There is also provided a method for monitoring a blade of a wind turbine.

Abstract: A ram air turbine (RAT) in which a cam follower is operably coupled to turbine blades such that a cam follower position determines turbine blade pitch.

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 method of deploying offshore wind turbine assemblies includes mounting a wind turbine assembly horizontally on a vessel and transporting the wind turbine assembly to an offshore site. The wind turbine assembly is raised to a vertical condition at the site and attached to anchor weights. Blades are attached to the turbine head after the wind turbine assembly is in the vertical condition. In one embodiment, the wind turbine assembly can include a tower including tapered lower and upper sections joined together at their respective wide ends, a turbine head connected to the upper section, and a platform connected to the lower section. The platform includes a buoy tank partially filled with ballast to provide mass and buoyancy. A wave piercing cowling is rotatively attached to the lower section. The turbine head can include an adjustable journal bearing, scabbard blade mounts, and a gearless induction generator with flux adjusting capabilities.

Abstract: A blade adjusting device for a wind turbine is connected to a plant safety chain and can open and close the plant safety chain by activating a switch. If a fault is detected in one of the blade adjusting devices, the respective control unit can open the plant safety chain. By opening the safety chain, a signal is sent to the blade adjusting devices, and so all the blade adjusting devices initiate a synchronous safety operation of at least two rotor blades when the signal is received.

Abstract: A ram air turbine assembly includes a governor shaft rotatable about an axis and a stop shaft coupled for rotation with the governor shaft. A rotatable housing portion surrounds at least a portion of the stop shaft. A lock plunger extends through an opening in the rotatable housing portion to prevent rotation of the rotatable housing portion and minimize vibration impact loading when stowed.

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 variable pitch propulsor system with a propeller pitchlock system having a pitchlock solenoid valve located in communication with a pitchlock pressure circuit to selectively actuate pitchlocking in response to a controller. The pitchlock solenoid valve includes an electro-mechanical device which is normally closed but may be commanded to electrically open and dump the pitchlock pressure which causes actuation of the pitchlock system. The pitchlock solenoid provides a mechanism which will selectively pitchlock the propulsor system; permits a built in test routine to determine the condition of the pitchlock system through a commanded propeller pitchlock sequence; requires no mechanical link between the rotating and non-rotating propeller components to initiate pitchlock; is independent of engine and gearbox configurations; and can initiate pitchlock remotely with a signal from a remote location.

Abstract: A turbine with vanes and tethers that adjust to the wind includes: an axle, adapted to be positioned perpendicular to the airflow; a radial spar attached to the axle; a vane rotatably attached to the spar; and a positioning element to limit the vane from rotating substantially more than a perpendicular angle away from the spar. The device retains the vane in a position that utilizes the airflow to rotate the axle. The positioning element is a tether attached to the distal point of the vane.

Abstract: An abutment mechanism for limiting the flapping of the blades of a rotor (1). High abutment members (6) can be moved into an engagement position by return means (13) exerting an intrinsic return force (R), and into a disengagement position by a flyweight (10) exerting a centrifugal force (C) under the effect of the rotor (1) rotating. At least one magnetic type bistable latch (15) is in selective engagement with the high abutment members (6). When the rotor (1) is stationary and while it is starting to rotate, an engagement latch (15) engages with the high abutment member (6) to prevent it passing from the engagement position towards the disengagement position. At a predetermined centrifugal force threshold, the engagement of the engagement latch (15) with the high abutment member (6) is broken, and the high abutment member (6) quickly passes into the disengagement position.

Abstract: A system and method for pitching a rotor blade in a wind turbine are disclosed. The method includes collecting in an individual pitch controller for the rotor blade a pitch offset angle relative to a collective pitch angle. The method further includes determining a synchronized pitch offset angle. The method further includes, after an emergency condition occurs, pitching the rotor blade towards the synchronized pitch offset angle.

Abstract: A variable pitch propulsor system with a propeller pitchlock system which utilizes a follower style pitchlock ballscrew screw which tracks the actuator axial stroke. The pitchlock system transfers the propeller yoke loads, from the ballscrew ballnut to the pitchlock nut allowing the propeller to pitchlock; utilizes the same screw thread lead angle for normal ballscrew back driving operation as well as pitch locking capabilities; provides a single ballscrew which is capable of both being back driven by the ballnut and structurally adequate for reacting the blade loads resulting from any flight condition; and minimizes the requirement of additional rotation and torque transferring interfaces between the ballscrew and pitchlock nut.

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: The present patent application provides a wind turbine with variable blade pitch. The wind turbine with variable blade pitch includes a turbine shell coaxially disposed at a turbine axis; and at least three evenly distributed blade handle bases fixedly disposed at the outer circumference of the turbine shell. A blade handle axis is coaxially configured on each blade handle base. A blade is fixedly disposed on each blade handle axis. A centrifugal blade pitch changing unit is disposed on the turbine shell and configured to adjust the rotation speed of the wind turbine. When the rotating speed of the wind turbine exceeds the rated rotating speed, it is regulated by the centrifugal blade pitch changing unit, so as to avoid the rotating speed of the wind turbine to be greatly increased due to the wind speed rise and make the wind turbine run stably at the rated rotating speed.

Abstract: Proposed is a hydraulically controlled variable pitch propeller system for air, land or water craft, comprising an engine, an engine controller, a rotating propeller featuring at least two propeller blades (16), for the pitch control of which a propeller governor (30) is provided connecting the propeller (10) via at least one hydraulic line and comprising a governor body (32) housing a control spool (46) the position of which is determined by the cooperation of flyweights (40) rotating by means of the engine and a variably biased governor spring (48) supported by the control spool (46). In accordance with the invention, the propeller governor (30) comprises an electric motor (58) which sets the preload of the governor spring (48) for the desired rpm and is electrically connected to the engine controller.

Abstract: A method for monitoring wear of a blade pitch brake within a rotor blade pitch control system of a wind turbine is described. The rotor blade pitch control system includes a blade pitch actuator. The method includes engaging the blade pitch brake and measuring a blade pitch displacement while the blade pitch brake is engaged. The method further includes determining a brake wear level based on the measured blade pitch displacement while the blade pitch brake is engaged, and generating a brake wear level output signal corresponding to the brake wear level.

Abstract: An overspeed protection system for a wind turbine having a hub and at least one rotor blade mounted to the hub includes a rotation sensor adapted for measuring a rotor speed of said wind turbine; a comparator connected to the rotation sensor and adapted for comparing the measured rotor speed with a predetermined threshold value of the rotor speed wherein the comparator outputs a signal indicative of the comparison; and an auxiliary pitch drive controller connected to the comparator and adapted to receive the signal indicative of the comparison, the auxiliary pitch drive controller being further adapted for controlling a pitch drive unit of the wind turbine independently of a main turbine controller and, if the threshold value is exceeded, to adjust a pitch angle of the rotor blade of the wind turbine so that aerodynamic braking of the wind turbine is effected.

Abstract: The invention relates to aeronautical engineering, in particular to methods of flight due to creating of forces on air propellers, namely using thrust vectoring of direction and amount of force created by air propellers of opposite rotation with the axis, mainly in the direction of flight, in the expanded range of speeds, from 50 m/s to high near-sonic speed of flight. The invention may be applied for horizontal flight and maneuvering in flight on vertical take-off aircrafts using rotation of main rotors from the vertical stand of rotor axes during the take-off to almost horizontal position of rotor axes in horizontal flight, thus both the rotation of rotors and the change of position of an aircraft together with its rotors may be applied, and it may be also used in the horizontal take-off aircrafts with almost horizontal position of axes during the horizontal flight, including the planes with airscrew propellers.

Abstract: An eolic turbine is disclosed, comprising: a hub (1) revolvingly mounted on a tower, around a basically horizontal axis, and provided with a slow speed shaft that drives into rotation a rotor of an electric generator, a plurality of blades (P) radially protruding from the hub (1) and revolvingly mounted around their axis, and an adjusting device of the blade pitch to adjust the angle of rotation of each blade around its axis. The adjusting device of the blade pitch comprises a geared motor (6) comprising a rotary case (60) fixed to a mobile plate (5) joined to the blade (P), and a fixed case (61) fixed to a fixed plate (7) joined to the hub (1).

Abstract: A power generating system wherein a turbine is mounted on top of a tower or tethered underwater. The turbine includes a rotor having a main blade connected to a rotor hub and an extender section. An adjusting device positions the extender blade between a retracted position within the main blade and to an extended position to expose more or less of the rotor to the fluid flow. The adjusting device includes a servo-controlled rack and pinion mechanism that converts rotation of the pinion by a servomotor into linear motion of the extender blade. A generator is connected to the turbine for generating electrical energy.

Abstract: Proposed is a hydraulically controlled variable pitch propeller system for air, land or water craft, comprising an engine, an engine controller, a rotating propeller featuring at least two propeller blades (16), for the pitch control of which a propeller governor (30) is provided connecting the propeller (10) via at least one hydraulic line and comprising a governor body (32) housing a control spool (46) the position of which is determined by the cooperation of flyweights (40) rotating by means of the engine and a variably biased governor spring (48) supported by the control spool (46). In accordance with the invention, the propeller governor (30) comprises an electric motor (58) which sets the preload of the governor spring (48) for the desired rpm and is electrically connected to the engine controller.

Abstract: A method for operating a wind energy installation, in particular for adapting a wind energy installation (10) to given wind conditions, the wind energy installation (10) having a rotor (16), which can be driven by wind, with at least two rotor blades (20), whose respective angles of incidence of the wind can be adjusted by means of at least one adjustment device, and having a generator for converting the mechanical energy of the rotor (16) to electrical energy. During operation of the wind energy installation, parameters are measured with spatial and/or temporal resolution on the side of the wind energy installation (10) facing the wind, said parameters describing the wind conditions in the measurement region, preferably the wind speed and/or the wind direction.

Abstract: A rotorcraft rotor with hinged blades, includes: a hub; a plurality of blades hinged to flap relative to the hub; bottom abutments of the hub, and bottom abutments of the blades suitable for co-operating with the bottom abutments of the hub; and top abutments of the hub, and top abutments of the blades suitable for co-operating with the top abutments of the hub; the top abutments of the hub being movable between a deployed position in which they extend facing the top abutments of the blades, and a retracted position in which they are offset angularly away from the top abutments of the blades. The rotor also includes elements for locking the top abutments of the hub in the deployed position, and inertial means for releasing the top abutments of the hub and for deactivating the locking means.

Abstract: A variable rotor blade mechanism for use in a gas turbine engine comprises a blade rotor, a blade, a harmonic drive system, a stepper motor and a bracket. The blade rotor rotates absolutely about an axial engine centerline during operation of the gas turbine engine. The blade extends radially from the blade rotor and is configured to be adjustable by rotation about a radial axis. The harmonic drive system is mounted to the blade rotor and connected to the blade to rotate the blade about the radial axis. The stepper motor drives the harmonic drive with relative rotational input with respect to the absolute rotation of the blade rotor. The bracket is disposed about the engine centerline and supports the stepper motor stationary with respect to the rotation of blade rotor such that the relative rotational input to the stepper motor is generated.

Abstract: A ram air turbine (RAT) prevents release of its turbine blades due an over-speed condition by detecting an over-speed condition with a turbine hub-mounted centrifugally operated trigger mechanism and rotating the blades to a fixed coarse pitch position with a release mechanism that responds to the trigger mechanism.

Abstract: An improved ram air turbine for generating emergency aeronautical supplemental power with a plurality of concentric or nested linear bearings for supporting a speed governor yoke plate on a speed governor shaft comprising a movable sleeve that supports the yoke plate and rides on the governor shaft.

Abstract: A propeller control system provides for actuation through supply pressure only. A transfer bearing thereby requires only a single land. The supply pressure is metered at a pitch change valve within the rotating propeller shaft downstream of the transfer bearing to provide hydraulic pressure for actuation and control. A feather override mode is provided by energizing a feathering solenoid. The increased supply pressure changes the hydraulic force balance of the pitch change valve to allow the increased supply pressure into a Coarse Pitch chamber and simultaneously allow fluid within the Fine Pitch chamber to flow to drain pressure. The flow to drain changes the hydraulic balance on the Pitch Change Actuator Piston to drive a pitch link attached to each propeller blade and thereby change the pitch thereof towards coarse pitch.

Abstract: A wind power plant for producing electrical energy on a large scale, comprising a base, a housing, rotatable on said base around vertical axis. A wind tail, attached to the housing, rotate the housing toward direction of the wind, utilizing the power of the wind, and produces additional tunnel suction to the flow of the wind from front side to back side of the housing. A plurality of turbines, equipped with rotors with wide blades, is mounted inside the housing one above another. Deflectors cover from the wind the front side of the rotors above their axis of rotation while computer controlled governors are covering the remaining front side of the rotors below their axis of rotation, keeping steady the speed of rotation of the rotors. Working surfaces of turbines are covered from heavy snow and during the storm and protected from birds. Power plant saves the area of occupied land, utilizing higher speed of wind on higher elevations.

Abstract: A hydraulically reversible, adjustable propeller unit for aircraft, land vehicles and watercraft, with a propeller with at least two blades, the pitch of which is controllable by means of a control unit (controller), whereby a hydraulic connection exists between the rotating propeller and the stationary control unit for controlling the blade pitch, with a spring-preloaded piston actuated by means of a hydraulic fluid, and with adjustable mechanical stop means for the start position, the brake position and the cruising or sailing position, whereby the piston is designed as a spring-preloaded double piston consisting of an inner piston and a ring piston arranged around the inner piston, said two pistons being lockable with each other by means of a centrifugal-force locking mechanism; the stop means for the start position is designed for limiting the setting range of the locked double piston in order to prevent unintentional reversing at speeds above about 1500 rpm; and the brake position can be reached only whe

Abstract: A centrifugally activated variable damper assembly for a stopped-rotor aircraft is disclosed for adjusting dampening level of teetering motions produced by the rotors during the in-flight conversion process from rotary-wing to fixed-wing flight, or vise versa. The assembly includes a damper valve responsive to centrifugal forces produced by rotational speed of the aircraft rotor. The assembly also includes dampers within the rotor system that operate at variable damping levels in response to centrifugal forces acting upon the damper valve.

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: 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: The device includes anti-cone stops projecting outward from at least two coaxial rings that can rotate about the rotor axis on the top face of the hub. Flyweights are each mechanically joined to one of the rings by a mechanism for driving the latter in rotation from the "ground" position, in which each anti-cone stop is facing an upper bearing shoe of the corresponding blade, to the "flight" position, in which the anti-cone stops are retracted against elastic mechanisms returning them to the "ground" position.

Abstract: A variable pitch propeller apparatus for use with a motor is disclosed. The apparatus includes a housing having a plurality of blades mounted therein for rotation. Adjustable high pitch and low pitch stop rings are connected to the housing and a synchronizer ring is slidably received by the housing and positioned between the stop rings. The synchronizer ring is limited in movement by the desired position of the adjustable high pitch stop ring and adjustable low pitch stop ring. A plurality of springs are used to bias the blades in a low pitch position for trolling and when the spring force is overcome by the thrust on the blades, the blades pivot to a high pitch position. The springs are cooperatively connected to the synchronizer ring or to the blades so that blade movement is coordinated and simultaneous. A tensioning ring is connected to the housing for simultaneously adjusting the tension on the springs.

Abstract: The device comprises anti-cone stops projecting outwards from a common ring that can rotate about the rotor axis on the top face of the hub and flyweights are each individually joined to the ring for driving the latter in rotation from the "ground" position, in which each anti-cone stop is facing an upper bearing shoe of the corresponding blade, to the "flight" position, in which the anti-cone stops are retracted, returning them to the "ground" position.