PROPOSED in this paper, for which its authors are receiving the Wright Brothers Medal for 1949, is an all-pneumatic system to provide the auxiliary power required by turbine-propelled multiengine aircraft.
Compressed air to drive various auxiliary power consumers is obtained by extraction from the compressors of the main propulsion turbines and from a special form of auxiliary gas turbine.
This turbine is effective primarily when the main engines are inoperative, and it may be used to start the latter.
By proper use of air extracted from the main engines, fuel consumption chargeable to auxiliary power appears, according to the authors, to be as low as for any competitive system. Furthermore, the amount of air extracted is shown to be well within generally accepted limits.