Patent ID: 8246302

Claim:
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 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 for providing 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; a piston movable within the piston tube along a piston axis, wherein the piston is connected to the rotor by a pin connection; a working fluid, wherein the working fluid is displaced as a function of movement of the piston; a groove defined at or near the interior surface of the piston tube in a generally axial direction with respect to the piston axis for allowing the working fluid to pass between a first volume defined at a first side of the piston and a second volume defined at an opposite second side of the piston, wherein the groove has a radial depth, and wherein the radial depth varies along the piston axis; and an additional groove defined at or near the interior surface of the piston tube in the generally axial direction for allowing the working fluid to pass between the first volume and the second volume, wherein the groove and the additional groove have different axial lengths.