75 Engine Air System
TTP B1-L3 ATA 75 Beech 90 Series B2-L1 Air Engine Air System 00 General 10 Engine Anti-icing 20 Accessory Cooling 30 Comp r essor Cont r ol 40 Indicating AIR SYSTEMS - DESCRIPTION AND OPERATION 1. General Three separate air systems are provided for the engine; one system for bearing compartment sealing, the second for cooling air, and the third for the compressor bleed valve and airframe services. 2. Description and Operation A. General Air pressure is utilized to seal the Nos. 1, 2 and 3 bearing compartments and to cool the compressor and power turbine disks and compressor turbine guide vanes. Pressure air is used in conjunction with labyrinth seals which consist of two separate parts. One part is in the form of a plain rotating surface, sometimes vented; the other part consists of a stationary circular seal with deep annular grooves in the bore. These parts together form an air seal when matched. The running clearance between each pair of rotating ...