Windmills for Aircraft Generators: The Manufacture and Wind‐Tunnel Testing of a Centrifugally Operated Variable‐Pitch Type

THE usual method of driving aero‐generators is by means of a small windmill mounted on the shaft of the generator, the contour of the latter being streamlined. By this means a separate prime mover is dispensed with, while, if the windmill is placed in the slip‐stream of the main airscrew, some of the lost energy is re‐generated. The inherent drawback to this form of drive is, however, that the speed of a normal windmill—and hence of the generator armature—varies with the speed of the aircraft, and many methods have been devised to overcome this trouble.