The turbonator: Design and development

THE BASIC configuration of the electric generating systems used on aircraft has been changing rapidly in recent years. This change has carried from the wide-speed-range 30-volt d-c systems used on most World War II planes to the constant-frequency 400-cps (cycle per second) a-c systems used on newer aircraft. The advent of constant-frequency requirements on airplanes with variable-speed engines necessitated the development of techniques for supplying constant-speed shaft power to the generators. In some cases this is done with shaft power supplied through variable gear ratio devices and in other cases by fixed-speed air turbines operating on high-pressure air bled from the jet engine compressor. Regardless of the approach used, the electric system designer faces two major problems; overall system weight must be minimized, and the system components must be compatible with the severe environmental conditions associated with high-performance aircraft. Both of these problems promise to become more severe in future aircraft.1