Abstract: The invention allows orientation of the platform (1) in order to obtain conditions of maximum efficiency in the wind turbine (16). It comprises first sensors (8) for detecting an effective rotation axis angle (?) formed between the rotation axis (2) and a horizontal plane (24); second sensors (9) for detecting wind direction (23); platform orientation means (11) for modifying the effective rotation axis angle (?); and at least one control unit (12) adapted for receiving a first input (13) from the first sensors (8) and a second input (14) from the second sensors (9) and, based on said inputs (13, 14), transmitting orders to the platform orientation means (11) and yaw mechanism.

Abstract: A method for adjusting the azimuth of a wind power plant, in which, during an azimuthal rotation of a machine housing with a rotor on a tower of the wind power plant, a constant residual pressure for generating a constant residual holding torque is applied to at least one azimuth braking device. Also an azimuth adjustment system for a wind power plant and to a wind power plant. In the disclosed method, the constant residual pressure and/or the constant residual holding torque are/is set as a function of at least one wind speed parameter before commencement of the azimuthal rotation, and the residual pressure and/or the residual holding torque are/is not changed during the azimuthal rotation, in particular during energization of azimuth drive motors.

Abstract: One or more controllers may perform one or more methods to control one or more air deflector units of one or more wind turbine rotor blades. The methods include per-blade control methods that may be performed, e.g., to reduce blade loading caused by wind gusts. The methods also include collective control methods that may be performed, e.g., to reduce tower motion and/or rotor speed.

Abstract: The present subject matter is directed to systems and methods for detecting rotor asymmetry of a wind turbine. The method includes measuring wind condition at a location downwind of the rotor for a plurality of rotor positions. Another step includes storing the measured wind condition(s) in predetermined wind bins. The method also includes analyzing the stored wind conditions for each of the predetermined wind bins. If a particular wind bin reaches a certain threshold of captured data points, then the method includes determining a variance between each of the stored wind conditions for the predetermined wind bins that have reached the threshold, wherein a variance between any one of the measured wind conditions greater than a predetermined amount is indicative of rotor asymmetry.

Abstract: Control method for a wind turbine which comprises the steps of obtaining a first signal regarding the azimuthal position for each blade, obtaining at least one signal indicative of wind speed, and calculating a blade pitch angle control term. The step of calculating the blade pitch angle control term comprises the use of at least one function dependent on the at least one signal indicative of wind speed and the at least one function dependent on the at least one signal indicative of wind speed includes an increasing piece within a range of wind speed values below a nominal wind speed.

Abstract: A method for determining the inclination of a tower, in particular of a wind turbine, in relation to the gravitational field, by evaluating the output signal from an acceleration sensor configured to pick up static acceleration in the direction of a sensor measurement axis, which method is simple to use and can be carried out on any wind turbines. It is proposed that the acceleration sensor is attached to a component, preferably to a main frame, which can be rotated about the longitudinal axis of the tower in an azimuth angular range of at least 180°, such that the sensor measurement axis is oriented substantially parallel to the plane of rotation of the component, the output signals, in the case of various azimuth angles, being successively measured and recorded by rotating the component between measurements, the inclination being determined by evaluation of the series of measurements obtained.

Abstract: Measurement exchange networks and protocols to exchange measurements of a parameter amongst devices (e.g., IoT devices), select the best measurement(s), accuracy/precision-wise, and determine a process variable for a control system based on the selected best measurement(s). A device may select a peer-provided best measurement to output as the process variable in place of a local measurement, and/or compute the process variable from multiple best measurements (e.g., local and/or peer-provided measurements). Metadata may be used to select a measurement(s) and/or to increase reliability/trust of exchanged data. In this way, each device of an exchange group/network may obtain the highest measurement accuracy of all available collocated sensors with little or no additional processing or cloud connectivity.

Abstract: The present subject matter is directed to a system and method for operating a wind turbine. The method includes determining an actual operating time for one or more wind turbine components at multiple power levels; determining a corresponding wind condition for each of the operating times at each power level; estimating a loading condition acting on the one or more wind turbine components at the multiple power levels and the corresponding wind conditions; estimating an accumulated fatigue life consumption of the one or more wind turbine components based at least partially on the operating times and the estimated loading conditions; and, operating the wind turbine based on the accumulated fatigue life consumption.

Abstract: The invention relates to a wind turbine comprising a rotor hub (7) rotating about a rotor axis (8), rotor blades (9, 10, 11) extending radially with respect to the rotor axis (8) at the same angular spacing relative to one another, and a remote wind gauge (19) that is fastened externally on the surface of the hub (7) in a mounting (20) and oriented such that wind characteristics at a distance in front of the hub (7) can be ascertained or measured, wherein the remote wind gauge (19) is arranged between two neighbouring rotor blades (9, 10) and in the radial direction of the rotor axis (8) and the mounting (20) is fastened to a respective blade bearing flange (21, 22) in the region of the connection of the rotor hub (7) to the rotor blades (9, 10), such that the remote wind gauge (19) can be retrofitted to the wind turbine (1).

Abstract: Counterweight systems for a wind turbine comprising a hub mounted to a nacelle such that the hub is rotatable around a rotation axis with respect to the nacelle, the hub comprising a blade root region configured to receive a root of a blade and having a pitch system configured to rotate the blade around a pitch axis. The counterweight system comprises a beam mountable to the blade root region at a first point of the beam and a counterweight mass coupled to the beam at a second point of the beam, such that, when the beam is mounted to the blade root region, the beam is arranged substantially perpendicular to the pitch axis and the pitch system can cause the counterweight mass to rotate around the pitch axis. Methods are also provided of mounting one or more blades to a wind turbine hub by using such counterweight systems.

Abstract: A turbine blade has hollowness, and is provided with a back-side wall of which a portion of the inner wall surface is exposed at the rear edge portion, with cooling air flown along the inner wall surface at the exposed region; and a recess provided in the inner wall surface at the exposed region. The contour of the recess (5) viewed from the normal direction of the inner wall surface of the back-side wall is set to a shape that is symmetrical centered on a reference axis (L) that intersects the flow direction of cooling air, and that broadens along the reference axis (L).

Abstract: An annulus filler, mounted to a rotor disc of a gas turbine engine and bridging the gap between two adjacent blades attached to the rotor disc, is disclosed. The annulus filler, formed from a polymer matrix composite material, includes an outer lid, defining an airflow surface for air drawn through the engine in an axial airflow direction, and a support structure, connectable to the rotor disc, to support the rear of the lid on the rotor disc. The support structure has two support walls extending from opposing lateral sides of the lid to an attachment strap for receiving a hook on the rotor disc, the attachment strap bridging the support walls. Under centrifugal loads, the opposing support walls resiliently deform. Each support wall has a concave rear edge. Each rear edge has a first curved section, a second curved section and a substantially straight section therebetween.

Abstract: In an apparatus for controlling an outboard motor mounted on a boat and having an internal combustion engine and a variable pitch propeller, characteristics defining a desired pitch angle of the propeller that makes fuel consumption minimum relative to a navigation speed of the boat are memorized and the pitch angle of the propeller is controlled to the desired pitch angle that is corresponding to the navigation speed detected by a navigation speed detector in accordance with the characteristics.

Abstract: An engine control device having a calculator for calculating a pitch setpoint for at least one propeller of the engine, the calculator taking account at least of a flight speed.

Abstract: An annulus filler is provided for mounting to a rotor disc of a gas turbine engine and bridging the gap between two adjacent blades attached to the rotor disc. The annulus filler is substantially entirely formed from a polymer matrix composite material. It has an outer lid which defines an airflow surface for air being drawn through the engine in an axial airflow direction, and a support structure which is connectable to the rotor disc to support the lid on the rotor disc. The support structure has two support walls extending from opposing lateral sides of the lid to an attachment strap for receiving a hook on the rotor disc, the attachment strap bridging the support walls. In use, under centrifugal loads, the opposing support walls resiliently deform to allow outward radial movement of the lid. Each support wall is thickened in a region neighboring the attachment strap.

Abstract: An aircraft electrical power generation system includes an AC generator having a rotor including a plurality of electromagnetic rotor-windings and stator including plurality of electrical stator-windings. The rotor mechanically coupled to a shaft of a gas turbine engine by transmission-system. The generator includes a frequency controller, a torque sensor determining a torque on the transmission-system by the generator and controller to operate the system in first and second modes. In first mode, the power output frequency of the generator controlled by the frequency controller within limits, and reduced idle signal going to a turbine engine controller. In second mode, the power output frequency of the generator not controlled by the frequency controller and increased idle signal going to the turbine engine controller. The controller operates the system in first mode when the torque is below a limit, and in second mode when the torque is above a limit.

Abstract: A method for controlling operation of a power generation and delivery system while increasing a power output of the power generation and delivery system is described. The method includes, monitoring an output parameter of the power generation and delivery system and determining a rate of change of the output parameter as a function of time. A reactive current command signal is generated a as a function of the determined rate of change of the output parameter. Operation of a power converter is controlled based at least partially on the reactive current command signal to facilitate maintaining a substantially constant terminal voltage as the power output of the power generation and delivery system is increased.

Abstract: A free stream fluid kinetic energy conversion device combines a large diameter freewheeling primary rotor with small diameter secondary power takeoff rotors placed within the lift induced blade tip vortices of the primary rotor. This enables use of high rotational speed generating units and avoids diseconomy of scale in gearbox expense. The device partially recovers otherwise lost blade tip vortex energy. The freewheeling primary rotor transmits no reaction torque to the support structure. Resilient buoyant tether deployment accommodates transient eddy induced structural loads.

Abstract: The invention relates to a device (10) for manufacturing a fiber composite component (3, 4, 5), which is connected to an attachment element (22), for a rotor blade (2) of a wind turbine (1), wherein the fiber composite component (3, 4, 5) is or will be manufactured from at least one fiber material (15, 21) and at least one matrix material, wherein the attachment element (22) is provided with a first region (221) arranged outside of the fiber composite component (3, 4, 5) and a second region (222) integrated into the fiber composite component (3, 4, 5), comprising a manufacturing mold (11) for the fiber composite component (3, 4, 5) with a recess (12), wherein the recess (12) has a first region (121) for receiving the first region (221) of the attachment element (22), and a retention device (13), by means of which fluid matrix material is or will be retained from the first region (121) of the recess (12).

Abstract: Aerodynamic root adapters for rotor blades include an interior support section having a first end that connects to a root end of the rotor blade and a second end that connects to a rotor hub of the wind turbine, and, an aerodynamic exterior section supported by the interior support section. The aerodynamic exterior section thereby extends an aerodynamic profile of the rotor blade beyond the root end of the rotor blade to at least partially between the root end of the rotor blade and the rotor hub when the aerodynamic root adapter is connected thereto.

Abstract: A method and apparatus for controlling a propeller of a contra-rotation open fan (CROF) engine of an aircraft is provided. A diameter of the propeller is set to be at a first diameter during at least a portion of a first flight condition of the aircraft. The diameter of the propeller is set to be at a second diameter, different from the first diameter, during at least a portion of a second flight condition of the aircraft.

Abstract: The invention relates to a drive (1) of a tail rotor (12) of a helicopter (10) by a permanently excited transversal flux machine in duplex arrangement in such a way that between two stators (4), which each have a toroidal winding system (8), there is arranged a disc-shaped impeller (5), which has permanent magnets (15) and on the outer circumference of which propeller blades (14) of the tail rotor (12) are arranged.

Abstract: A pitch system (20) for rotating a blade (4) of a wind turbine relative to a hub (6) generally comprises a bearing (22) having an inner bearing ring (30) configured to be mounted to the hub and an outer bearing ring (32) configured to be mounted to the blade. A first coupling member (24) positioned between the hub and inner bearing ring extends radially inward. A second coupling member (26) positioned between the blade and outer bearing ring extends radially inward and over the inner bearing ring. A drive system (28) includes a first drive member (34) coupled to the first coupling member and a first driven member (36) coupled to the second coupling member. The first drive member is configured to move the first driven member to rotate the outer bearing ring relative to the inner bearing ring and thereby pitch the blade.

Abstract: Disclosed is a system and method for monitoring wind turbines, generally comprising a microphone for picking up acoustic emissions from a wind turbine and outputting a signal corresponding to the emissions; a filter for splitting the signal into a plurality of signals according to a plurality of frequency bands; and a processor for processing the plurality of signals and generating sound level data corresponding to at least a subset of the frequency bands. The system compares the sound level data with a sound threshold and generates an alarm signal when the sound level data exceeds the sound threshold. Alternatively, the system may include different thresholds corresponding to the different frequency bands, and an alarm can be generated when one or more of the different thresholds are exceeded by the different signals in the different frequency bands.

Abstract: The invention relates to a method for detecting icing and other loadings on blades of wind turbines. Advantageously, the method utilizes existing wind turbine actuators, for example pitch actuators, far excitation of blade vibrations. Vibration sensors on the blade such as strain sensors or accelerometers measure the blade vibrations excited in response to the actively excised vibrations. By comparing the measured response with previously obtained reference responses, it is possible to determine if blade icing is present.

Abstract: A control system for a wind turbine includes a detecting system configured to determine at least one of a rotor load, a wind shear, a wind speed, and a load imbalance due to wind shear. An adjusting system is configured to adjust a shaft moment set point correction value based on at least one of the rotor load, the wind shear, the wind speed, and the load imbalance. A compensating system is configured to compute a shaft moment correction command based on the shaft moment set point correction value output from the adjusting system. A pitch system is configured to adjust a pitch of at least one blade of the wind turbine based on the shaft moment set point correction command, or a yaw system is configured to adjust the yaw position of a rotor based on the shaft moment set point correction command.

Abstract: A method of controlling a wind turbine rotor blade, the blade comprising a pitch axis about which the blade can be pitched, and a flap movable to alter the aerodynamic profile of the blade, the method comprising the steps of: providing a pitch angle request (?) to a pitch actuator; determining an initial flap angle request (?_flap); providing a decoupled flap angle request (?) to a flap actuator; herein the decoupled flap angle request (?) is calculated from the pitch angle request (?) and the initial flap angle request (?_flap) such that the decoupled flap angle (?) provided to the flap actuator does not counteract the pitch angle request (?); and pitching the blade according to the pitch angle request (?) and moving the flap according to the decoupled flap angle request (?).

Abstract: The present invention is directed to a rotor blade assembly for a wind turbine. The rotor blade assembly includes a rotor blade extending from a blade root to a blade tip. The rotor blade has a pressure side surface and a suction side surface. The pressure side surface and the suction side surface each extend between a leading edge and a trailing edge. The assembly also includes a blade root extension configured to attach to one of the pressure side surface or the suction side surface of the rotor blade adjacent to the blade root. The blade root extension includes at least one blade fence and at least one airflow modifying element. The blade fence extends between a proximal end and a distal end in a chord-wise direction. The proximal end is configured to attach to the rotor blade such that the distal end remains free and spaced apart from the rotor blade. The airflow modifying element is configured at the proximal end of the blade fence.

Abstract: A floating wind turbine (1) for electric power production and a method for use of the wind turbine (1) is described. The wind turbine (1) includes a hull (2) attached to a supporting column (2?) for a wind turbine (3) arranged to be put into rotation by wind force acting on rotor blades (3?). The wind turbine (1) is connected to a buoyancy device (4) by a coupling device (5). The buoyancy device (4) encircles at least a portion of the hull (2) and supports at least a portion of the mass of the wind turbine (1). The coupling device (5) is a rotary coupling arranged in such a way that the wind turbine (1) is able to rotate an angle from an essentially vertical position towards a horizontal position, or the opposite. The hull (2) is provided with an adjustable ballast (9, 12) arranged to balance the wind turbine (1) about the rotary coupling (5) in any position between the positions.

Abstract: An aircraft engine including: a stator; a main shaft; a first rotor; a second rotor; a transmission mechanism; a first electrical apparatus supported by the first rotor and a second electrical apparatus supported by the second rotor; at least one first field winding supported by the stator; a control unit configured to circulate direct electric current in the first field winding; at least one first armature winding supported by the first rotor and connected to the first electrical apparatus and at least one second armature winding supported by the second rotor and connected to the second electrical apparatus.

Abstract: A method for monitoring a state of a drive train of a wind power plant. The drive train including at least one component which is mechanically connected to a rotating element of the drive train and at least one acceleration sensor connected to the rotating element and located at a distance from a rotational axis of the drive train. The at least one acceleration sensor is configured to rotate about the rotational axis of the drive train at the distance. A signal of the at least one acceleration sensor is sensed in terms of its timing at least one rotational speed of the rotating element and is examined for interference frequencies which correspond to damage in the drive train.

Abstract: An individual blade control system (IBCS) for a rotor system having a rotor hub is provided including a plurality of blade cuffs mounted to the rotor hub. Each blade cuff is configured to receive a rotor blade and rotate about a blade axis. A plurality of electrical actuators is mounted to the rotor hub adjacent at least one of the plurality of blade cuffs. Each electrical actuator is configured to rotate about an actuator axis. The plurality of blade axes and the plurality of actuator axes are arranged in a plane. Each electrical actuator is coupled to an adjacent blade cuff such that rotation of one of the plurality of electrical actuators causes a proportional rotation of one of the blade cuffs.

Abstract: A device for setting a turbomachine propeller blade is provided. The setting device includes a first disc and a second disc respectively provided with first and second coupling devices, the first and second discs being coaxial; and a system for tilting at least one of the first and second discs with respect to the other. During a tilting of at least one of the first and second discs with respect to the other, the coupling distance of the at least one blade on the first and second discs remains constant, bringing about the rotation of the at least one blade.

Abstract: Described embodiments include a wind turbine system. In this embodiment, the system includes a wind turbine including a rotor blade having a controllable feature and attached to a rotor hub drivingly coupled to an electric generator. The controllable feature is configured if activated to decrease a noise generated by the rotor blade and correspondingly to decrease electric power generated by the electric generator. The wind turbine system includes a sensor configured to detect a parameter indicative of present or possible future noise generation state of the rotor blade. The wind turbine system includes a noise manager circuit configured to select a noise mitigation measure responsive to the detected parameter and in compliance with a minimum electric power generation requirement assigned to the wind turbine. The wind turbine system includes a control circuit configured to activate the controllable feature in response to the selected noise mitigation measure.

Abstract: The present application provides a turbine blade cooling system. The turbine blade cooling system may include a first turbine blade with a first turbine blade platform having a cooling cavity in communication with a pressure side passage and a second turbine blade with a second turbine blade platform having a platform cooling cavity with a suction side passage. The pressure side passage of the first turbine blade platform is in communication with the suction side passage of the second turbine blade platform.

Abstract: A method for controlling a gas turbine engine includes: generating model parameter data as a function of prediction error data, which model parameter data includes at least one model parameter that accounts for off-nominal operation of the engine; at least partially compensating an on-board model for the prediction error data using the model parameter data; generating model term data using the on-board model, wherein the on-board model includes at least one model term that accounts for the off-nominal operation of the engine; respectively updating one or more model parameters and one or more model terms of a model-based control algorithm with the model parameter data and model term data; and generating one or more effector signals using the model-based control algorithm.

Abstract: A laminated rotor and an electric machine including the laminated rotor are disclosed. In an embodiment, a rotor comprises a plurality of stacked laminations, wherein each lamination includes a plurality of radially extending slots arranged about a circumference of each of the plurality of laminations, and the plurality of radially extending slots in successive laminations in the stack are aligned. A stud member passes longitudinally through at least one hole in the lamination stack, and a plurality of coils are positioned within the plurality of slots. Fewer than all of the plurality of slots have a coil positioned therein, leaving at least three slots empty. Balance members may be placed in the slots that do not have a coil positioned therein to balance the rotor.

Abstract: The present invention relates to a control system and an associated method for controlling an amount of reactive power delivered from a wind power plant to an associated power supply grid, the control system comprising a wind power plant controller and a number of wind turbine controllers each being in communication with said wind power plant controller, wherein the wind power plant controller is adapted to provide a grid voltage reference in response to a required total amount of reactive power to at least one wind turbine controller, said wind turbine controller comprising a voltage control loop comprising means for cancellation of a steady-state local voltage error.

Abstract: A distributed heating system for a power train of a ram air turbine, which ram air turbine has a stowed position and a deployed position, has at least one electrical resistance heater element, with each electrical resistance heater element located proximate at least one respective lubrication surface for the power train; and an electrical controller for coupling electrical power to each electrical resistance heater element when the ram air turbine is in the stowed position and ambient temperature falls below a desired level.

Abstract: A rotor blade for a rotary wing aircraft includes a root region extending from a rotor head to about 15% to 20% of a blade radius, a main region extending from a radial extent of the root region to about 80% to 95% of the blade radius, and a tip region extending from a radial extent of the main region to a blade tip. At least a portion of one of the root region, the main region and the tip region includes an airfoil profile section defined by a scaled set of coordinates in which a set of y/c coordinates listed in Table I are scaled by a selected factor.

Abstract: A vertical takeoff and landing aircraft includes rotors that provide vertical and horizontal thrust. During forward motion, the vertical lift system is inactive. A lift fan mechanism positions the fan blades of the aircraft in a collapsed configuration when the vertical lift system is inactive and positions the fan blades of the aircraft in a deployed configuration when the vertical lift system is active.

Abstract: The present invention describes methods to fabricate actuators that can be remotely controlled in an addressable manner, and methods to provide remote control such micro-actuators. The actuators are composites of two permanent magnet materials, one of which is has high coercivity, and the other of which switches magnetization direction by applied fields. By switching the second material's magnetization direction, the two magnets either work together or cancel each other, resulting in distinct “on” and “off” behavior of the devices. The device can be switched “on” or “off” remotely using a field pulse of short duration.

Abstract: A rotor blade for a wind turbine is disclosed. The rotor blade may generally include a shell having a pressure side and a suction side. The shell may define an outer surface along the pressure and suction sides over which an airflow travels. The rotor blade may also include a spoiler having a fixed end and a free end. The fixed end is connected to the outer surface so as to enable a hinge action, such as a living hinge. The free end includes a top flange and a bottom flange configured to engage opposite sides of the shell and is pivotal relative to the fixed end between a recessed position and an elevated position. The free end has a range of motion limited by contact of the top flange and the bottom flange with the shell. Further, the spoiler is configured to separate the airflow from the outer surface when the spoiler is in the elevated position.

Abstract: A method for operating a wind turbine includes: providing a curve defining optimal pitch angle as a function of tip speed ratio or as a function of wind speed; modifying at least a part of the optimal pitch angle curve by applying a safety buffer, thereby obtaining a safety modified pitch angle curve; operating the wind turbine in accordance with the safety modified pitch angle curve; measuring one or more parameters regarding wind conditions and/or loads on one or more component of the wind turbine; adjusting the safety buffer, based on the measurements, thereby obtaining an adjusted pitch angle curve; and operating the wind turbine in accordance with the adjusted pitch angle curve. Since the safety buffer is adjusted based on measured parameters, it can be reduced if actual operating conditions are less severe than expected. This allows the wind turbine to be operated in a more optimal manner.

Abstract: In an embodiment of the invention, a non-rotating wind energy generator uses the fluid flow principles of vortex shedding and transverse galloping to generate oscillatory, linear motion of a beam, and linear alternators, optionally located near both ends of the beam, generate electrical power when the beam is in motion.

Abstract: An automatic adjustment device for adjusting inclination of blades of wind turbines includes a first housing having multiple blades connected thereto and each blade has a first connection portion which is inserted into the firs housing. A transmission unit is connected to the first housing. A pump unit and a speed-changing member are mechanically connected to the transmission unit. The pump unit is mechanically connected to the speed-changing member. The pump unit has a driving unit which is connected with a transmission disk which is connected to the connection portions of the blades. The pump unit is activated by speed difference between the speed-changing member and the transmission unit so as to rotate the transmission disk via the driving unit, and adjust the inclination angle of the blades to protect the blades and increase the efficiency of the wind turbine.

Abstract: The invention concerns a method for the determination of an azimuth angle for servicing purposes (?w) of a wind power plant with a machinery housing that is rotatable on a tower through an azimuth angle (?) and a rotor that is rotatable on a machinery housing through a rotor angle (?) such that a plurality of combinations of rotor angles (?) and azimuth angles (?) is adjusted, that are determined at the rotor subject to the influence of a turbulent wind field, which is effecting torques, for the adjusted combinations of rotor angles (?) and azimuth angles (?) and the associated azimuth angle (?), a torque envelope of the torque-azimuth angle associations is determined, surrounding areas (U(?)) with comparable sector sizes of the azimuth angle (?) are generated and associated magnitude values of the torque envelope are determined, a surrounding area (U(?w)) with magnitude-wise smaller torque envelope values than the neighboring surrounding areas is selected and the azimuth angle for servicing purposes (?w) is

Abstract: A method for determining a mass change at a rotating blade of a wind turbine is provided. The method includes measuring a vibration quantity representative of a vibration of the wind turbine, measuring an azimuthal quantity representative of a rotation angle of the blade, determining a frequency quantity representative of a vibration frequency of the blade from the vibration quantity and the azimuthal quantity, and determining the mass change at the blade based on the frequency quantity.

Abstract: A lead lag damper (10, 11) for a helicopter rotor unit has a rotor and a hub (8), said rotor having N rotor modes, with N being the number of blades. This centered single lead lag damper (10, 11) for the entire rotor unit has an essentially cylindrical shape, with an elastomer material shear element between a first side (7) and a second side (9) having a homogenous resistance to shear deformation and being axially preloaded, so that the lead lag damper (10, 11) acts in a homogenous manner in the rotor inplane eigenmodes. Thus, the lead lag damper (10, 11) acts as a single unit on the critical inplane mode of the rotor, which is having N identical blades (1-4). The elastomeric material is loaded by a uniform shear deformation in contrary to the commonly used oscillatory deformation.

Abstract: A root extender for coupling a rotor blade to a hub of a wind turbine is disclosed. The root extender may generally include a body defining a longitudinal axis between a first end and a second end. The first end may define a first planar surface configured to be positioned adjacent to the hub and the second end may define a second planar surface configured to be positioned adjacent to the rotor blade. The second planar surface may be oriented at a cone angle relative to the first planar surface. In addition, the longitudinal axis may be oriented at a non-perpendicular angle relative to the first planar surface.