Abstract: The invention relates to a rotational device that is to be used in a fluid in order to generate power from the moving stream of a fluid or to convert energy into a motion of a fluid. Said rotational device comprises main rotating means which is fixedly connected to a central rotary shaft of the rotational device, one or several rotational surfaces which are mounted on the main rotating means so as to be rotatable about rotational surface rotary shafts spaced away from the rotary shaft such that the main rotating means are able to perform a rotational motion about the central rotary shaft by means of at least one rotational surface, the rotational surface rotary shafts extending parallel to the rotary shaft of the main body. A device is provided which adjusts an angle of the rotational surface relative to the direction of flow of the fluid in such way that the buoyancy principle is maintained on the rotational surface.

Abstract: The invention relates to a rotational device that is to be used in a fluid in order to generate power from the moving stream of a fluid or to convert energy into a motion of a fluid. Said rotational device comprises main rotating means which is fixedly connected to a central rotary shaft of the rotational device, one or several rotational surfaces which are mounted on the main rotating means so as to be rotatable about rotational surface rotary shafts spaced away from the rotary shaft such that the main rotating means are able to perform a rotational motion about the central rotary shaft by means of at least one rotational surface, the rotational surface rotary shafts extending parallel to the rotary shaft of the main body. A device is provided which adjusts an angle of the rotational surface relative to the direction of flow of the fluid in such way that the buoyancy principle is maintained on the rotational surface.