In the rotor of a windmill electric generator, blades are secured to a hub by means of individual tab-receiving slots and a common "knock-off" hubcap, this mounting means providing for rapid assembly and disassembly. The mounting structure itself establishes a predetermined pitch at the blade root, thus permitting the advantages of an optimum twisted blade to be obtained without the need for an excessively complex blade configuration. The result is a compact generator unit that can be used easily in remote areas and stowed with camping equipment.