Abstract: A wind blade for a wind turbine has a tip and a root. The wind blade extends along a first longitudinal axis. The root is suitable for attachment to a hub of a wind turbine. The root has a tubular shape and a base defining a crown extending around the first longitudinal axis. The crown has a plurality of first connection openings spaced apart along the crown. Each first opening has an inner surface defining a first helical coupling portion. In particular, the first helical coupling portion comprises a groove which develops helically to accommodate and allow attaching by screwing a connecting device suitable to attach the root of the blade to the hub.

Abstract: A wind turbine that has a blade extending along an axis is made of a composite material made of filaments. A method for manufacturing the blade includes: laying on a first mould a plurality of sheets of fibre of a material, laying second moulds above the plurality of sheets of the fibre material, laying on the second moulds sheets of a fibre material, laying a third mould on the first mould to create at least one closed volume between the first mould and the third mould inside of which the plurality of sheets of fibre laid down and the second moulds are housed, injecting fluid material having resin to impregnate the plurality of sheets, removing the first and third moulds from the outside of a blade that is formed, and removing the second moulds from the inside of the blade through a cavity of the blade.