A wind turbine system comprising: a shaft; a rotor for driving the shaft, the rotor comprising a first blade engaged to the shaft by a hub, wherein the first blade has a degree of freedom to pivot relative to the shaft, and wherein a first teeter angle (β) is defined between an instantaneous position of the first blade and a time-averaged plane of rotation of the first blade; and a first fluidic teeter control assembly engaged between the rotor and the shaft configured to provide a first dynamic teeter restraining force as a function of the first teeter angle and a fluidic resistance, wherein the first dynamic restraining force is relatively low when the first teeter angle is within a first teeter operation range, and wherein the first dynamic restraining force varies such that the first dynamic restraining force is higher when the first teeter angle is outside the first teeter operation range, wherein the first fluidic teeter control assembly comprises: a piston tube that defines an interior surface, wherein the piston tube is connected to the shaft by a pin connection (54, 66); a piston movable within the piston tube along a piston axis, wherein the piston is connected to the rotor by a pin connection; and a working fluid, wherein the working fluid is displaced as a function of movement of the piston; and characterised in that the wind turbine system further comprises: a sensor configured to sense an azimuthal position of the first blade; an external fluid circuit connected to a first volume of the piston tube defined at a first side of the piston and a second volume of the piston tube defined at an opposite side of the piston at the axial extremities of the piston tube; and a variable resistance valve positioned within the external fluid circuit configured to adjust resistance to displacement of the working fluid as a function of the sensed azimuthal position of the first blade. a shaft; a rotor for driving the shaft, the rotor comprising a first blade engaged to the shaft by a hub, wherein the first blade has a degree of freedom to pivot relative to the shaft, and wherein a first teeter angle (β) is defined between an instantaneous position of the first blade and a time-averaged plane of rotation of the first blade; and a first fluidic teeter control assembly engaged between the rotor and the shaft configured to provide a first dynamic teeter restraining force as a function of the first teeter angle and a fluidic resistance, wherein the first dynamic restraining force is relatively low when the first teeter angle is within a first teeter operation range, and wherein the first dynamic restraining force varies such that the first dynamic restraining force is higher when the first teeter angle is outside the first teeter operation range, wherein the first fluidic teeter control assembly comprises: a piston tube that defines an interior surface, wherein the piston tube is connected to the shaft by a pin connection (54, 66); a piston movable within the piston tube along a piston axis, wherein the piston is connected to the rotor by a pin connection; and a working fluid, wherein the working fluid is displaced as a function of movement of the piston; and characterised in that the wind turbine system further comprises: a sensor configured to sense an azimuthal position of the first blade; an external fluid circuit connected to a first volume of the piston tube defined at a first side of the piston and a second volume of the piston tube defined at an opposite side of the piston at the axial extremities of the piston tube; and a variable resistance valve positioned within the external fluid circuit configured to adjust resistance to displacement of the working fluid as a function of the sensed azimuthal position of the first blade. a sensor configured to sense an azimuthal position of the first blade; an external fluid circuit connected to a first volume of the piston tube defined at a first side of the piston and a second volume of the piston tube defined at an opposite side of the piston at the axial extremities of the piston tube; and a variable resistance valve positioned within the external fluid circuit configured to adjust resistance to displacement of the working fluid as a function of the sensed azimuthal position of the first blade.