Abstract: An airfoil for a fan section of a turbine engine may include a fan blade or an outlet guide vane, and an edge guard attached thereto. The edge guard may include a heating conduit disposed within at least a portion of the edge guard. An anti-icing system for a plurality of fan blades or outlet guide vanes may include a fluid supply pathway configured to supply heating fluid to respective ones of a plurality of heating conduits within the edge guards attached to respective ones of a plurality of fan blades and/or to a plurality of outlet guide vanes. The heating fluid may include bleed air from a core air flowpath. A method of inhibiting icing on an airfoil may include flowing a heating fluid into a heating conduit disposed within an edge guard attached to the airfoil and heating the edge guard with the heating fluid.

Abstract: A thermally isolated sensor associated with a gas turbine engine includes a sensor probe configured to measure a temperature of a fluid associated with the gas turbine engine, and a base to be coupled to the gas turbine engine. The thermally isolated sensor includes a leading projection coupled to the base that extends into the fluid. The leading projection is configured to be heated by a heat source associated with the gas turbine engine. The thermally isolated sensor includes a trailing projection coupled to the base that extends into the fluid. The trailing projection is downstream from the leading projection. The trailing projection includes an inlet, and the sensor probe is disposed within the inlet and thermally isolated from the leading projection.

Abstract: A radially flexible connection joint for a gas turbine engine includes an exhaust manifold flange operatively coupling an exhaust cylinder to an exhaust manifold of the gas turbine engine. The exhaust cylinder includes a cylindrical flange that extends radially outwardly from a rotation axis of the gas turbine. The cylindrical flange defines a downstream axial face. The exhaust manifold is positioned downstream from the exhaust cylinder. The exhaust manifold includes an upstream edge. The exhaust cylinder and the exhaust manifold are substantially coaxial with the rotation axis of the gas turbine. The exhaust manifold flange has a bellows portion that extends radially between the cylindrical flange of the exhaust cylinder and the upstream edge of the exhaust manifold. The bellows portion permits relative radial motion of the exhaust cylinder and the exhaust manifold.

Abstract: A system and method are provided for controlling a wind turbine in response to a blade liberation event. Accordingly, estimated response signatures for the wind turbine are determined. Sensor data indicative of at least two actual response signatures of components of the wind turbine to a rotor loading are collected. The actual response signatures are compared to the estimated response signatures. The two or more actual response signatures meeting or exceeding the estimated response signatures is indicative of a blade liberation event. In response to detecting the blade liberation event, a rapid shutdown control logic is initiated to decelerate the rotor at a rate which exceeds a nominal deceleration rate of the rotor.

Abstract: Provided is an apparatus and method for cooperative controlling wind turbines of a wind farm, wherein the wind farm includes at least one pair of turbines aligned along a common axis approximately parallel to a current wind direction and having an upstream turbine and a downstream turbine. The method includes the steps of: a) providing a data driven model trained with a machine learning method and stored in a database, b) determining a decision parameter for controlling at least one of the upstream turbine and the downstream turbine by feeding the data driven model with the current power production of the upstream turbine which returns a prediction value indicating whether the downstream turbine will be affected by wake, and/or the temporal evolvement of the current power production of the upstream turbine; c) based on the decision parameter, determining control parameters for the upstream turbine and/or the downstream turbine.

Abstract: The present invention relates to a method of controlling a wind turbine comprising a tower supporting a rotor comprising a plurality of pitch-adjustable rotor blades. The method includes obtaining a movement signal indicative of a lateral movement of the tower; determining a pitch modulation signal, based on the movement signal, for actuating a rotor blade to produce a desired horizontal force component to counteract the lateral movement of the tower; determining a radial force component acting on a rotor blade; determining a phase offset parameter for the rotor blade based on the radial force component; and, transforming the pitch modulation signal into a pitch reference offset signal for the rotor blade based on the phase offset parameter.

Abstract: Methods and systems for governing an aircraft propeller of an engine are described. The method comprises obtaining a fluid flow command for speed control of the propeller, determining pulse parameters of a pulse width modulated valve control signal for actuating a two-position solenoid valve in accordance with the fluid flow command based on an average fluid flow through the solenoid valve and an opening and closing time of the solenoid valve, generating the valve control signal with the pulse parameters as determined, and transmitting the valve control signal to the solenoid valve for actuating the solenoid valve, thereby controlling the speed of the propeller.

Abstract: A blade pitch adjustment mechanism includes a pitch cylinder having a first face and pitch slots extending longitudinally from the first face, a blade sleeve having a second face and a blade slot extending longitudinally from the second face, the blade sleeve is configured to be rotationally positioned in the pitch cylinder with the second face located with the first face, wherein the blade slot and the pitch slots are cooperative to form keyway, corresponding to a discrete blade pitch, when the blade slot is aligned with a pitch slot.

Abstract: According to certain aspects of the disclosure, a computer-implemented method may be used for rotorcraft track and balance. The method may include capturing one or more images of at least one rotating blades of a rotorcraft and analyzing the one or more images of the at least one rotating blades to determine blade information. Additionally, the method may include determining a location of the at least one rotating blades in the one or more images based on the blade information and calculating blade position information based on the determined location of the at least one rotating blade and a parameter of a user device capturing the one or more images. Additionally, the method may include displaying the blade position information to the user device and displaying instructions on one or more adjustments to the at least one rotating blades of the rotorcraft based on the blade position information.

Abstract: In a method, impulse response information indicative of an impulse response is determined based on an impulse introduced into a lightning conductor and characterized by an electromagnetic wave. The impulse response information representing at least a waveform and a travel time determined after the introduction of the impulse based on reflection thereof. Evaluation information is specified based on the determined impulse response information. The impulse response information is analyzed at least with respect to the represented waveform and travel time of the introduced and reflected electromagnetic wave. The evaluation information is indicative of whether or not the lightning conductor is functional. The determined evaluation information is output. Also disclosed are a device for practicing this method, a rotor blade for a wind turbine that includes at least one lightning conductor and a device for practicing the method, and a system with one or more devices for practicing the method.

Abstract: A ceiling fan comprising a motor having a rotating blade hub and a downrod mount. The ceiling fan also has multiple blades mounted to the rotating blade hub. The downrod has an upper end configured to mount to a structure and a lower end with a mount motor. The ceiling fan also has multiple studs provided in one of the downrod mount or the motor mount and corresponding openings provided in the other of the downrod mount or the motor mount. The studs are received within the openings to aid in securing the downrod to the motor assembly.

Abstract: A main shaft assembly of a wind turbine and method for manufacturing the same are provided. Accordingly, the main shaft assembly includes a structural/shaft body defining a cavity therein. The shaft body is configured to transmit a load of the wind turbine developed in response to the wind. An inner body is located within the cavity. The inner body is non-loadbearing with respect to the load. At least one sensor is coupled to the inner body and positioned within the cavity for detecting a deflection of the shaft body in response to the load.

Abstract: A sensor signal comprising a first signal pulse having a first voltage amplitude and a second signal pulse having a second voltage amplitude greater than or substantially equal to the first voltage amplitude is obtained from a sensor positioned adjacent a feedback device coupled to rotate with an aircraft-bladed rotor about a longitudinal axis and to move along the axis with adjustment of the rotor's blade pitch angle. The feedback device comprises a reference feature configured to generate the second signal pulse and varying detectable feature(s) configured to generate the first signal pulse and to cause a change in the first voltage amplitude as a function of an axial position of the feedback device along the axis. A voltage ratio is determined based on the first voltage amplitude and the second voltage amplitude, and the axial position of the feedback device is determined from the voltage ratio.

Abstract: The diagnostic system for diagnosing a rotor imbalance of a wind turbine based on acceleration data measured on a nacelle of a wind turbine which is supported by a tower includes a measuring device provided with a triaxial vibration sensor suitable for measuring acceleration data corresponding to vibrations occurring on the nacelle. The system also includes a processing system for processing the acceleration data, suitable for determining the rotor imbalance according to the acceleration data measured on at least two axes on the nacelle. The invention also relates to a method for diagnosing the rotor imbalance of a wind turbine.

Abstract: A method of controlling a propeller assembly, having a blade, piston end cap, and piston, with a pitch control unit, having a transfer bearing and a blade angle unit, the method comprising: axially moving a transfer tube relative to and circumscribing the transfer bearing, and sensing an axial movement of the transfer tube with the blade angle unit.

Abstract: The disclosure proposes a yaw calibration method and system for a wind turbine. The calibration method includes: establishing a cylindrical coordinate graph of wind resource distribution based on historical wind farm operation data, to determine a wind direction interval of main inflow wind conditions of a wind farm; calculating an effective value of active power of each wind speed sub-interval, and obtaining a fitted power curve of each refined interval through curve fitting; and setting an angle between a central axis of a refined interval for a fitted power curve corresponding to a calibration curve in each wind speed range and a central axis of the to-be-calibrated wind direction interval as a yaw error calibration value in the wind speed range, to establish a wind speed-yaw error calibration value lookup table; and determining a yaw error calibration value under a current wind direction and a current wind.

Abstract: A wind turbine including yaw control comprising a controller receiving an input signal, and providing an output control signal to a yaw actuator. The input signal to the controller is based on: a first feedback signal that is indicative of the relative wind direction determined with respect to the wind turbine, wherein the first feedback signal is filtered with a first low pass filter; and a second feedback signal that is indicative of the activity of the yaw actuator. The control technique of the invention significantly improves the ability of a yaw system to maintain a zero degree yaw error during steady state wind conditions, or in other words to maintain an accurate heading of the nacelle pointing into the wind, as well as reducing the maximum yaw error experienced during yaw system activation.

Abstract: There is provided a blade angle feedback system for an aircraft-bladed rotor rotatable about a longitudinal axis and having an adjustable blade pitch angle. A feedback device is coupled to rotate with the rotor and to move along the axis with adjustment of the blade pitch angle. The feedback device comprises a body having position marker(s) embedded therein, the body made of a first material having a first magnetic permeability and the position marker(s) comprising a second material having a second magnetic permeability greater than the first. Sensor(s) are positioned adjacent the feedback device and configured for producing, as the feedback device rotates about the axis, sensor signal(s) in response to detecting passage of the position marker(s). A control unit is communicatively coupled to the sensor(s) and configured to generate a feedback signal indicative of the blade pitch angle in response to the sensor signal(s) received from the sensor(s).

Abstract: According to one implementation, a damage detection system includes: a physical quantity detection unit, a flight condition changing part and a damage detection part. The physical quantity detection unit detects a physical quantity of a structural object composing an aircraft during a flight of the aircraft. The flight condition changing part changes at least one flight condition of the aircraft to at least one specific flight condition when the physical quantity of the structural object has been detected by the physical quantity detection unit. The damage detection part determines whether a damage arose in the structural object, based on a physical quantity which has been detected, from the structural object of the aircraft flying with the at least one specific flight condition, by the physical quantity detection unit.

Abstract: A hub for a wind turbine is longitudinally extended along a longitudinal axis between a front tip and a rear shaft flange is provided. The hub comprises: at least one blade flange for connecting a respective blade to the hub, at least one top edge on an external surface of the hub, the top edge being positioned with respect to a vertical direction over the front tip, when the hub is positioned in a service position, a plurality of service steps, each step) being oriented for permitting an individual to move between the front tip and the top edge or between the rear shaft flange and the top edge when the hub is positioned around the longitudinal axis in the service position.

Abstract: The blades for a rotor of a gas turbine engine are all manufactured to the same design. However, manufacturing tolerances mean that in practice each individual blade is different to the others. It is proposed to arrange the blades around the circumference of the rotor in a manner that limits excessive stress being induced in the blades due to differences in the vibration response between a given blade and its two neighbouring blades.

Abstract: A wireless sensor antenna system for a turbomachine including a rotating blade including a passive sensor is disclosed. The wireless sensor antenna system includes an antenna extending continuously along a circumferential interior surface of a casing of the turbomachine that surrounds the rotating blade. The antenna is configured to receive a return wireless signal from the passive sensor. A power transmission element extends along the at least portion of the circumferential interior surface of the casing to power the passive sensor by emitting an electromagnetic signal to power the passive sensor.

Abstract: The blades for a rotor of a gas turbine engine are all manufactured to the same design. However, manufacturing tolerances mean that in practice each individual blade is different to the others. It is proposed to arrange the blades around the circumference of the rotor in a manner that limits excessive stress being induced in the blades due to differences in the vibration response between a given blade and its two neighbouring blades.

Abstract: According to some embodiments, a system and method are provided to model a sparse data asset. The system comprises a processor and a non-transitory computer-readable medium comprising instructions that when executed by the processor perform a method to model a sparse data asset. Relevant data and operational data associated with the newly operational are received. A transfer model based on the relevant data and the received operational data. An input into the transfer model is received and a predication based on data associated with the received operational data and the relevant data is output.

Abstract: A system and method for determining a position of a feedback ring of a propeller of an aircraft engine are provided. The feedback ring is coupled to the propeller to rotate with the propeller and to be displaced along a longitudinal axis with adjustment of a blade angle. An engagement member is configured to engage the feedback ring and to be displaced along a longitudinal direction substantially parallel to the longitudinal axis with displacement of the feedback ring. A sensor comprises a first member coupled to the engine and a second member coupled to the engagement member. The second member is moveable relative to the first member along the longitudinal direction as the engagement member is displaced. The sensor generates a signal indicative of a longitudinal position of the second member relative to the first member. A controller determines an axial position of the feedback ring from the sensor signal.

Abstract: A blade adapter for rotor blades of wind turbines, for increasing the rotor diameter, has a first end for attaching to the rotor hub, and a second end, spaced apart in the axial direction, for connecting to the blade root of a rotor blade. In addition, the blade adapter, at its first and second end, has a pitch circle for connecting to the rotor hub or to the rotor blade, wherein the wall of the blade adapter extending in the axial direction is open outwardly, in the form of a truncated cone, from the first end toward the second end, in at least one portion.

Abstract: The present disclosure is directed to a method for detecting a mass imbalance in a rotor of a wind turbine. The method includes receiving, with a computing device, sensor data indicative of an operating characteristic of the wind turbine. The method also includes determining, with the computing device, a mean amplitude of a designated frequency component of the operating characteristic. Furthermore, the method includes determining, with the computing device, when a mass imbalance is present within the rotor based on the mean amplitude of the designated frequency component.

Abstract: A technical object of the present disclosure is to provide an anemometer for a wind turbine which is capable of precisely measuring a wind velocity and a wind direction. To this end, an anemometer for a wind turbine of the present disclosure is an anemometer for a wind turbine which is used for a wind turbine including a plurality of rotating blades and a hub which is equipped at a rotation center of the plurality of rotating blades and has a nosecone and is equipped in the nosecone.

Abstract: A support structure for a propulsor blade includes at least one sleeve configured to support a root portion of the propulsor blade, the at least one sleeve fixedly attached to a surface of the root portion. The support structure also includes a preloading component configured to apply a residual compressive force to the at least one sleeve and the root portion of the propulsor blade, the residual compressive force configured to maintain an attachment of the at least one sleeve to the root portion. The propulsor blade and root portion may incorporate composite structural materials. The support structure and/or the preloading component increases the high cycle fatigue strength and bending capacity of blade retention assemblies (including, e.g., composite-to-metal joints) when subjected to high cycle bending loads under reduced centrifugal load conditions, thereby making further reductions in the size and weight of blade retention assemblies feasible.

Abstract: There is provided a sliding component including, a first sliding part which is non-conductive and which has a sliding surface; and a conductive member provided in the first sliding part or provided on a side opposite to the sliding surface of the first sliding part.

Abstract: According to one implementation, a damage detection system includes: a physical quantity detection unit, a flight condition changing part and a damage detection part. The physical quantity detection unit detects a physical quantity of a structural object composing an aircraft during a flight of the aircraft. The flight condition changing part changes at least one flight condition of the aircraft to at least one specific flight condition when the physical quantity of the structural object has been detected by the physical quantity detection unit. The damage detection part determines whether a damage arose in the structural object, based on a physical quantity which has been detected, from the structural object of the aircraft flying with the at least one specific flight condition, by the physical quantity detection unit.

Abstract: A method for customizing bedplates for a plurality of wind turbines having different loading requirements. The method includes forming a plurality of baseline bodies for the bedplates that includes a near net shape of one of the bedplates. Further, the method includes determining a loading requirement of the bedplates of each of the wind turbines. Moreover, the method includes applying additional material to an exterior surface of the plurality of baseline bodies via an additive manufacturing process so as to customize a structural capacity of each of the bedplates such that the structural capacity of each of the bedplates can withstand the loading requirement for each of the wind turbines. Accordingly, the structural capacity of each of the plurality of baseline bodies may be the same or may be different.

Abstract: A system is described for performing structural health monitoring of an object under study. The system comprises a hollow cavity structure comprising one or more cavities obtained using additive manufacturing. The cavity structure is sealable from its environment and forms an integral part of the object under study. The cavity structure furthermore is connectable to a pressure sensor for sensing a pressure in the cavity structure.

Abstract: According to one implementation, a damage detection system includes: a physical quantity detection unit, a flight condition changing part and a damage detection part. The physical quantity detection unit detects a physical quantity of a structural object composing an aircraft during a flight of the aircraft. The flight condition changing part changes at least one flight condition of the aircraft to at least one specific flight condition when the physical quantity of the structural object has been detected by the physical quantity detection unit. The damage detection part determines whether a damage arose in the structural object, based on a physical quantity which has been detected, from the structural object of the aircraft flying with the at least one specific flight condition, by the physical quantity detection unit.

Abstract: The present invention provides a method of operating a wind turbine. The wind turbine comprises at least one rotatable blade. The method comprises the steps of providing a load sensor configured to generate a load signal representing loading on the blade, generating a first load signal when the blade is in a first position, and generating a second load signal when the blade is in a second position. Additionally, the method comprises steps of detecting a rotational speed of the blade, calculating a weight force on the blade based on the first and the second load signal, and calculating a centrifugal force on the blade based on the first and the second load signal. Subsequently, the weight force is compared with a predetermined weight force, and the centrifugal force is compared with a predetermined centrifugal force at the detected rotational speed. Finally, a risk of ice throw is determined based on the comparisons of the weight force and the centrifugal force with the predetermined forces.

Abstract: A sensor system for a wind turbine blade, the system comprising: a blade load sensor providing a load measurement; a processing unit interfaced with the blade load sensor and configured to provide a corrected load parameter as an output. The processing unit includes: an axial force estimation module that determines an estimated axial force on the wind turbine blade in a direction along the length of the blade; and a load calculation module that 10 determines the corrected load parameter based on the estimated axial force and the load measurement of the blade load sensor.

Abstract: Blade feedback systems and methods for determining a blade angle position and rotational speed of a plurality of propeller blades of a variable pitch propeller assembly are provided. Exemplary blade feedback system includes features for determining an axial position of a beta tube. Based at least in part on the axial position of the beta tube, the blade angle of the plurality of propeller blades can be determined. Exemplary blade feedback system can also include features for determining the rotational speed of the beta tube such that the rotational speed of the propeller blades can be determined.

Abstract: A rotor hub for a wind turbine may generally include a hub body defining both a plurality of blade flanges and a plurality of access ports spaced apart from the blade flanges. In addition, the rotor hub may include a ladder assembly extending within an interior of the hub body. The ladder assembly may include a plurality of platforms, with each platform defining a planar surface and being circumferentially aligned with a respective one of the plurality of access ports. The ladder assembly may also include a connecting frame extending between each pair of adjacent platforms so as to couple the adjacent platforms to one another. The connecting frame may extend lengthwise along a reference line defined between the adjacent platforms. The platforms may be positioned relative to one another such that the reference line extends at a non-perpendicular angle relative to the planar surfaces defined by the adjacent platforms.

Abstract: A propeller blade for rotation about a hub assembly is provided, wherein the propeller blade defines a radial direction along its length from a blade root to a blade tip, the propeller blade including a radially inner region, a radially outer region located between the blade root and the blade tip at a position where rotational forces on the blade are sufficient, in use, to remove ice from an uncoated blade, a coating disposed at least along a leading edge of the propeller blade, the coating including an icephobic material, wherein the coating extends along the propeller blade from the radially inner region to the radially outer region. The coating overlays a substrate portion of the propeller blade defining a color visually indicative of wear of the coating.

Abstract: A method of dynamically controlling a wind turbine having a rotor supporting a plurality of blades and a main bearing supporting the rotor, the method comprising detecting a load profile around the circumference of the main bearing, generating a control signal based on the detected load profile and dynamically adjusting the load profile of the main bearing using the control signal.

Abstract: Groups of wind turbines at a wind farm are controlled based on detection of volant animal swarms. A risk score is defined for each of a plurality of wind turbine groups of the wind farm at a default risk score based on predetermined data. A respective operational parameter is set for each wind turbine of each of the wind turbine groups based on the respective risk score. The presence of a volant animal swarm is detected in a region associated with a given one of the wind turbine groups via a volant animal detection system. The risk score of the given one wind turbine group and an adjacent wind turbine group is changed from the default risk score to temporary risk scores in response to detection of the volant animal swarm.

Abstract: To identify abnormal behavior in a turbine blade, a failure detection system generates a “fingerprint” for each blade on a turbine. The fingerprint may be a grouping a dynamic, physical characteristics of the blade such as its mass, strain ratio, damping ratio, and the like. While the turbine is operating, the failure detection system receives updated sensor information that is used to determine the current characteristics of the blade. If the current characteristics deviate from the characteristics in the blade's fingerprint, the failure detection system may compare the characteristics of the blade that deviates from the fingerprint to characteristics of another blade on the turbine. If the current characteristics of the blade are different from the characteristics of the other blade, the failure detection system may change the operational mode of the turbine such as disconnecting the turbine from the utility grid or stopping the rotor.

Abstract: A wind turbine including a plurality of blades, a micro inertial measurement unit installed on each blade and configured to sense a plurality of detection parameter signals at corresponding installation positions, and a monitoring system configured to monitor an operating state of the blades. The monitoring system includes a signal processing unit configured to obtain a processing parameter signal through calculation based on the detection parameter signals, a signal analyzing unit configured to analyze each analysis parameter signal, selected from the plurality of detection parameter signals and the processing parameter signal, to obtain a fault estimation signal, used to estimate whether a corresponding blade works in a fault state, and a fault evaluating unit configured to evaluate, based on a plurality of fault estimation signals, whether a corresponding blade fails or a probability that the corresponding blade fails.

Abstract: Method for testing a rotor blade ice detection system for a wind turbine, the rotor blade ice detection system being configured to output a warning in the event of icing of a rotor blade being monitored, the method having the following steps of: acquiring data relating to a rotor blade to be monitored, providing at least one value of an operating and/or environmental parameter, modifying the at least one value provided in such a manner that the at least one modified value differs from an actual value of the parameter, evaluating the data relating to the rotor blade to be monitored and the at least one modified value via the rotor blade ice detection system, and testing whether the rotor blade ice detection system outputs a warning.

Abstract: An electric arc detection system is presented. The electric arc detection system comprises a receiving antenna that receives electromagnetic radiation generated by an electric arc formed in an internal cavity of a non-conductive hollow structure, and a processing subsystem for determining an existence of the electric arc in the internal cavity based upon signals representative of the electromagnetic radiation.

Abstract: Method and apparatus for determining the deflection or curvature of a rotating blade, such as a wind turbine blade or a helicopter blade. Also, methods and apparatus for establishing an inertial reference system on a rotating blade.

Abstract: A wind turbine blade (22) is cantilevered from a shaft (50) of a rotor (20). A pitch reference azimuth (74) of the blade may be located by generating a function (66, 67, 68, 69) of gravitational bending strain or moment magnitude of the blade versus pitch angle of the blade for a vector component (85, 86) of gravitational force (GF) relative to a predetermined transverse line (CL, 83) of the blade, such as a chord line, over a range of pitch angles of the blade. The pitch reference azimuth may be set at a characteristic point (70, 71, 72) on the function, such as an inflection point Two such functions (67, 69) may be generated with the blade in two respective positions on opposite sides of the rotor The intersection point (73) of these functions is a pitch reference point that is compensated for rotor tilt.

Abstract: An apparatus for monitoring a machine element (02), which moves with respect to a base and rotates about its own axis, having a sensor (06) and evaluation electronics (09). According to the invention, the sensor (06) and the evaluation electronics (09) and also a power supply unit and a transmitter unit (12) are arranged on the moving machine element (02).

Abstract: A method for operating a wind turbine is provided. The method includes determining a wind condition, determining for the wind condition expected azimuthal positions of a rotating wind rotor of the wind turbine, and determining for the wind condition desired azimuthal positions of the rotating wind rotor so that at least one of a load balance of the rotating wind rotor and a power uptake of the rotating wind rotor is improved compared to the expected azimuthal positions.

Abstract: An assembly configuration between a wind turbine rotor blade and a rotor hub includes a rotor hub having one or more pitch bearings, with each pitch bearing having an outer diameter race and an inner diameter race. Rotor blades are affixed to the respective pitch bearing rings, with the rotor blades having a root end with an outer diameter. An adaptor is configured between the root end and the pitch bearing, with the adaptor affixed to the inner diameter race and the root end affixed to the adaptor. The adaptor defines a mounting surface for the root end radially inward of the pitch bearing such that the root end outer diameter is less than the diameter of the inner diameter race.