Abstract: An impeller for a windmotor consists of a rigid hub attached to a rotatingly mounted shaft, an outer rim concentric with the hub and a number of radial vanes of a flexible material, such as fabric, stretched between the hub and the rim, whereby their angle of inclination decreases from their inner to their outer ends. The rim is likewise made of a flexible, non-permeable fabric or other material in the shape of a hollow torus, which is filled with a gas at a pressure sufficient to maintain the shape of the torus under the stresses of wind and other forces. The torus may be filled with hydrogen or helium, whereby the entire impeller becomes lighter than air, thus eliminating the weight factor with regard to impellers with very large diameters.