Turbines arranged to extract energy from a streaming fluid—such as wind, steam, tidal streams and water waves—are usually optimized to reach maximum efficiency at a certain fluid speed, that is designed for a certain operating point. Basically, turbine designs assume a fluid velocity is present to give a lifting force on the rotor blades and so overcome the total drag and friction forces of the rotor and turbine in operation. Thereby, the turbine axis will rotate due to the moment produced by the lifting force that corresponds to the product of the second order pressure gradient of the fluid passing over the wing profile of the rotor blades times the distance to the axis of turbine rotation. This applies for conventional wind turbines, steam turbines and tidal turbinesto be transferred to the turbine by one or more joints, each one of which is exhibiting an attachment point shared with a rotor blade. Thus, the rotor and rotor blades may be joined to the turbine in several attachment points. In the said H-rotor design, the rotor is mounted to the turbine in two attachment points located symmetrically around the mid-normal plane of the rotor, that is centre supported; while the Darreus wind turbine NL19181 has a rotor supported in both ends by the turbine, that is double-end supported. Also known is a rotor supported in one end only, that is single-end supported; that is provided with straight rotor blades having an oblique axis of turbine rotation and joined to a central hub at the ground level.