NOVELTY - The rotor (3) has an annular rotor blade (2) having a blade profile (22) in cross-section and formed as a hollow profile. A polygon (1) with vertices is formed as rhombus, and is inscribed to the blade that is formed as pneumatically supported membrane construction. The profile is made of plastic/metal, where blade position (21) is changed between two of the vertices with a maximum distance from an uplift position into a down position so that an aero- and hydro-dynamically generated force pair of suction- and pressure forces with an offset torque acts on a rotational axis (30).    USE - Rotor for use as a flow converter, which is utilized as wind- or water turbine, to convert kinetic energy in flow into a rotational movement or as a flow generator to convert rotational movement into flow and as a ventilator, a vehicle e.g. aircraft and bicycle, rotor and a ship rotor.    ADVANTAGE - The annular rotor blade position is changed between the two of the vertices with the maximum distance from the uplift position into the down position so that the aero- and hydro-dynamically generated force pair of suction- and pressure forces with the offset torque acts on the rotational axis, thus realizing greater development of wind power as an environmentally-harmless energy source, and providing dynamic impulse in contrast to screwing effect while realizing stable construction, extremely light weight design and simple assembly of the rotor. The design of the rotor achieves quiet run, avoids low frequency vibrations, increases aero- and hydrodynamic effective surfaces, and realizes good startup characteristics during slight flow and automatic alignment for inflow while creating sustainability of rotational movement by appropriate mass distribution and enabling higher electrical power with same rotor diameter. The rotor realizes convenient loading of propellers and bearings and reduced rotational resistance.    DESCRIPTION OF DRAWING(S) - The drawing shows an isometric top view of a ship rotor.    Polygon (1)    Rotor blade (2)    Blade nose (20)    Blade position (21)    Blade profile (22)    Blade rear edge (24)    Rotational axis (30)