The invention relates to a wind turbine system (WTS) comprising at least two blade rotors rotatably mounted to a nacelle (rotatably) mounted to a tower provided above a (water) level. The WTS can be characterised in that the blade rotors are interconnected by one or more retractable blades. The retractable blades can have variable properties, they can be stowable, can be able to weathervane, and can comprise a defined construction, a working mean. The blade rotors can rotate in the same and/or opposite directions. The components can be fabricated of defined materials. The WTS can be provided in an array and it can be couplable or coupled with various mechanocomponents and/or electrocomponents. A method for varying a design point of the disclosed wind turbine is proposed.

A method of manufacturing a root ring for a wind turbine blade comprising winding metal sheet material onto a mandrel to form a metal section proximate a hub end of the root ring. Sheet fibre material is also wound onto the mandrel to form a fibre section of the root ring proximate a tipwards end of the root ring. The metal sheet material is interleaved with the sheet fibre material to form a transition section of the root ring between the metal section and the fibre section.

A method of replacing at least one tooth of a gear includes providing a tool jig including a mounting block with a plurality of indexing jig features. The tool jig also includes a tool-supporting feature in laterally movable contact with a jig rail feature. With at least one indexing jig feature, relative motion of the tool jig relative to the gear is resisted. A material-removal tool is operated, while attached to the tool-supporting feature in the tooth-removal position, to remove at least a portion of a working circumference of the gear including a native gear tooth to be replaced. Motion of the material-removal tool is guided to generate a circumferential gear cut including a relatively smooth first cut surface formed by removal of at least the native gear tooth to be replaced. The material-removal tool is removed from the tool-supporting feature. The tool jig is removed from the gear.

A method of manufacturing a root ring for a wind turbine blade comprising winding metal sheet material onto a mandrel to form a metal section proximate a hub end of the root ring. Sheet fibre material is also wound onto the mandrel to form a fibre section of the root ring proximate a tipwards end of the root ring. The metal sheet material is interleaved with the sheet fibre material to form a transition section of the root ring between the metal section and the fibre section.

A method of replacing at least one tooth of a gear includes providing a tool jig including a mounting block with a plurality of indexing jig features. The tool jig also includes a tool-supporting feature in laterally movable contact with a jig rail feature. With at least one indexing jig feature, relative motion of the tool jig relative to the gear is resisted. A material-removal tool is operated, while attached to the tool-supporting feature in the tooth-removal position, to remove at least a portion of a working circumference of the gear including a native gear tooth to be replaced. Motion of the material-removal tool is guided to generate a circumferential gear cut including a relatively smooth first cut surface formed by removal of at least the native gear tooth to be replaced. The material-removal tool is removed from the tool-supporting feature. The tool jig is removed from the gear.