A turbine adapted to production of useful energy from the motion of a streaming fluid and arranged at substantially right angles of the axis of turbine rotation to the current direction of the streaming fluid, comprising - at least one turbine roller bearing comprising a rotatable bearing housing and a non-rotatable bearing housing, and exhibiting a centre point and a centre line passing through said centre point; and - at least one hub arranged in fixed attachment to the rotatable bearing housing and to a supporting structure arranged in fixed attachment to the non-rotatable bearing housing; and - a blade body located in whole or in part in the fluid and arranged in attachment to the hub, wherein the motion of the streaming fluid makes the blade body feasible to rotate around the axis of turbine rotation which coincides with the centre line passing through a point identical to said centre point, and comprising - a plurality of rotor blades each of which extends continuously in the axial and radial direction of a helix exhibiting an axis coinciding with the axis of turbine rotation, and exhibits a handedness around the axis of turbine rotation and in a plane normal to the helix axis is provided with a cross section exhibiting a centre line normal to said cross section and a wing profile which is provided with two end sections, wherein a first end section is provided with a round nose oriented to coincide with the direction of rotation of the blade body and a second end section is provided with a taper oriented in the opposite direction of, wherein the turbine exhibits a point of intersection between the axis of turbine rotation and a line normal to the axis of turbine rotation, and characterized by - a plurality of blade joints each of which exhibits a point of intersection between the centre line of a first rotor blade and said line normal to the axis of turbine rotation and a point of intersection between the centre line of a second rotor blade and said line normal to the axis of turbine rotation, wherein the points of intersection (PN, PB1, PB2) are joined by a joint line which is normal to the axis of turbine rotation and exhibits an end point in, wherein the distance PN-PB1 is not equal to the distance PN-PB2, wherein said first and second rotor blade exhibit different hands around the axis of turbine rotation and are attached to each other by at least one of said blade joints, and the blade body exhibits a diameter and a mid-point coinciding with the point of intersection between the axis of turbine rotation and the mid-normal plane, wherein said blade joints are attached to each other by intermediate parts consisting of said rotor blades. - at least one turbine roller bearing comprising a rotatable bearing housing and a non-rotatable bearing housing, and exhibiting a centre point and a centre line passing through said centre point; and - at least one hub arranged in fixed attachment to the rotatable bearing housing and to a supporting structure arranged in fixed attachment to the non-rotatable bearing housing; and - a blade body located in whole or in part in the fluid and arranged in attachment to the hub, wherein the motion of the streaming fluid makes the blade body feasible to rotate around the axis of turbine rotation which coincides with the centre line passing through a point identical to said centre point, and comprising - a plurality of rotor blades each of which extends continuously in the axial and radial direction of a helix exhibiting an axis coinciding with the axis of turbine rotation, and exhibits a handedness around the axis of turbine rotation and in a plane normal to the helix axis is provided with a cross section exhibiting a centre line normal to said cross section and a wing profile which is provided with two end sections, wherein a first end section is provided with a round nose oriented to coincide with the direction of rotation of the blade body and a second end section is provided with a taper oriented in the opposite direction of, wherein the turbine exhibits a point of intersection between the axis of turbine rotation and a line normal to the axis of turbine rotation, and characterized by - a plurality of blade joints each of which exhibits a point of intersection between the centre line of a first rotor blade and said line normal to the axis of turbine rotation and a point of intersection between the centre line of a second rotor blade and said line normal to the axis of turbine rotation, wherein the points of intersection (PN, PB1, PB2) are joined by a joint line which is normal to the axis of turbine rotation and exhibits an end point in, wherein the distance PN-PB1 is not equal to the distance PN-PB2, wherein said first and second rotor blade exhibit different hands around the axis of turbine rotation and are attached to each other by at least one of said blade joints, and the blade body exhibits a diameter and a mid-point coinciding with the point of intersection between the axis of turbine rotation and the mid-normal plane, wherein said blade joints are attached to each other by intermediate parts consisting of said rotor blades.