Patent ID: 8231347

Claim:
An apparatus comprising: a wind turbine rotor hub; a plurality of blade assemblies, each of the blade assemblies including a base blade coupled to the hub and an associated end blade housed at least partially within the base blade, each of the end blades having a linkage system configured to extend and retract the end blade relative to its associated base blade in response to applied force; means for applying force to the linkage systems, wherein the force-applying means is located outside of the blade assemblies; and a plurality of blade-hub couplers, each of the blade-hub couplers connecting a different one of the blade assemblies to the hub, wherein means for applying force comprises a plurality of drive units, and wherein each of the drive units is located within a different one of the blade-hub couplers, includes at least one motor, and is configured to apply force to the linkage system of the blade assembly connected to the hub by the blade-hub coupler in which the drive unit is located.