A turbofan engine includes a fan and a fan actuation system. The fan has a plurality of fan blades. Each of the plurality of fan blades is rotatable about a pitch axis. The fan actuation system includes one or more actuators for rotating the plurality of fan blades about the pitch axis and one or more thrust bearings. The fan actuation system is characterized by a fan actuation system envelope in a range of 300 to 1860. The fan actuation system envelope is given by $\frac{N_{\mathrm{FB}}{D}_{\mathrm{FT}}{M}_{\mathrm{cruise}}}{\left(\frac{R_{\mathrm{TB}}}{N_{\mathrm{FB}}}\right)},$
where N.sub.FB is a number of the plurality of fan blades, D.sub.FT is a fan tip diameter of the plurality of fan blades, M.sub.cruise is a Mach number of the turbofan engine at cruise operating conditions, and R.sub.TB is a thrust bearing radius of the one or more thrust bearings.

A turbofan engine includes a fan and a fan actuation system. The fan has a plurality of fan blades. Each of the plurality of fan blades is rotatable about a pitch axis. The fan actuation system includes one or more actuators for rotating the plurality of fan blades about the pitch axis and one or more thrust bearings. The fan actuation system is characterized by a fan actuation system envelope in a range of 300 to 1860. The fan actuation system envelope is given by

[00001]$\frac{N_{\mathrm{FB}}{D}_{\mathrm{FT}}{M}_{\mathrm{cruise}}}{\left(\frac{R_{\mathrm{TB}}}{N_{\mathrm{FB}}}\right)},$

where N.sub.FB is a number of the plurality of fan blades, D.sub.FT is a fan tip diameter of the plurality of fan blades, M.sub.cruise is a Mach number of the turbofan engine at cruise operating conditions, and R.sub.TB is a thrust bearing radius of the one or more thrust bearings.

The invention provides a controller for a wind turbine having three rotor blades, the controller being for controlling activation of individual pitch control of the rotor blades. The controller is configured to receive a flap load signal, from a flap loading sensor of each of the three rotor blades, indicative of flap loading on each of the respective rotor blades. The controller is configured to determine, based on the received flap load signals, a statistical dispersion parameter of flap loading for each of the rotor blades, the statistical dispersion parameters being indicative of a wind event in a wind field in which the wind turbine operates. The controller is configured to control activation of individual pitch control based on the respective statistical dispersion parameters.

A method for protecting one or more components of a yaw system of a wind turbine includes monitoring one or more loading signals indicative of a yawing moment of a rotor of the wind turbine. The method also includes evaluating the one or more loading signals indicative of the yawing moment of the rotor. Further, the method includes predicting an optimal start time for the yaw system based on the evaluated one or more loading signals. Moreover, the method includes starting the yaw system at the optimal start time to minimize loading of the yaw system of the wind turbine.

One example includes a wind turbine yaw control fault detection system. The system includes current monitors that are each configured to monitor a current amplitude of a respective one of a plurality of yaw motors of a wind turbine and to generate a current signal that is indicative of the respective current amplitude. The system further includes a processor to compare the current amplitude of each of the yaw motors relative to each other and relative to at least one threshold based on the current signal from each of the current monitors. The fault detection algorithm further determines a fault condition associated with at least one yaw mechanical drive component of the wind turbine based on the comparison of the current amplitude of each of the yaw motors relative to each other and relative to at least one threshold.

A method for determining at least one blade misposition of a rotor blade of a rotor of a wind power installation having multiple rotor blades with an adjustable blade angle, wherein the blade misposition describes a blade angle variance of the blade angle of the rotor blade from a reference blade angle, the wind power installation has a nacelle having the rotor and an azimuth adjustment device, wherein a circumferential rotational position of the rotor is referred to as the rotor position, and the azimuth adjustment device has at least one activable azimuth actuator in order to adjust an azimuthal position of the nacelle, comprises the steps of a detection step comprising detecting an azimuthal movement of the nacelle while the at least one azimuth actuator is inactive, and a determination step comprising determining the blade misposition on the basis of the azimuthal movement detected in the detection step.

A turbofan engine for an aircraft includes a fan and a fan actuation system. The fan has a plurality of fan blades coupled to a fan shaft having one or more fan bearings. The fan blades are rotatable about a pitch axis. The fan actuation system is disposed within a fan hub and includes one or more actuators for rotating the fan blades about the pitch axis and one or more radial thrust bearings. The fan actuation system is characterized by a fan actuation system length envelope in a range of 8.5 to 24 and given by $\frac{N_{\mathrm{FB}}{D}_{\mathrm{FT}}}{L_{\mathrm{AXIAL}}\left(\frac{R_{\mathrm{TB}}}{N_{\mathrm{FB}}}\right)}.$
N.sub.FB is a number of the fan blades, D.sub.FT is a fan tip diameter of the fan blades, R.sub.TB is a thrust bearing radius of the radial thrust bearings, and L.sub.AXIAL is an axial length from a fan hub tip to the fan bearings.

A method is for controlling a wind turbine. The wind turbine has a tower, a nacelle, a rotor with at least two rotor blades and a yaw system with at least one yaw drive configured to rotate the nacelle about a vertical axis of the tower (yaw axis). A control signal for the at least one yaw drive depends on at least one signal indicative of the wind direction. The control signal for the at least one yaw drive further depends on at least one value indicative of a vibration mode of the rotor blades.

A control system for a floating offshore wind turbine (FOWT). The FOWT includes a floating base, a tower, a nacelle, and rotor with blades that harvest energy from wind passing the FOWT. Without a rigid support, however, the FOWT is able to move. The controller uses generator speed and platform pitch position of the FOWT as inputs and manipulates blade pitch and torque resistance to achieve stability.

A method is for testing a functionality of a system of a wind turbine. The system includes an electro-mechanical actuator, an energy storage unit, and an energy dissipating element connectable to the energy storage unit for selectively transferring energy from the energy storage unit to the energy dissipating element. The method includes: providing first information representative of an operating mode of the system, and, if the operating mode is a test mode: causing a discharging of energy from the energy storage unit and a supply of at least a portion of the discharged energy to the energy dissipating element; receiving measurements being representative of a state of at least one of the energy storage unit and the energy dissipating element during the discharging and the supply; and determining a functionality of at least one of the energy storage unit and the energy dissipating element based on the measurements.