(under subclass 53) Devices and arrangements for propelling aircraft at high altitudes, and devices peculiar to aircraft for permitting aircraft to be propelled to high altitudes.
(1) Note. For super-chargers in general, see Class 123, Internal-Combustion Engines, subclasses 434+.
(2) Note. For garments for aviators providing an oxygen supply, see Class 128, Surgery, subclass 202.11.
(3) Note. For arrangements providing breathable air and all sorts of applications, see Class 128, Surgery, subclasses 200.24+.
(4) Note. Search Class 454, Ventilation, subclasses 71+ for means to automatically maintain the air in aircraft cabins under pressure and subclasses 76+ for means to circulate air through aircraft cabins, where characteristics of aircraft propulsion, sustenation, or details of structure are not claimed.
