8-1. ARMY TM  5-6115-612-34 MARINE  CORPS  TM  6115-34/8 AIR  FORCE TO  35C2-3-471-2 CHAPTER 8 NAVY AG-320BO-MME-OOO MAINTENANCE  OF  ENGINE 8-1. GENERAL. The gas turbine engine the starter spur gear. The starter spur consists of the combustion chamber case gear transmits the power to a quill assembly, turbine assembly, and the shaft that drives the oil pump gear. gearbox. The engine is a single-shaft design with the compressor and turbine d. Overhaul. The overhaul proce- wheels mounted on a common shaft. Power dures follow the methods and use the produced  by  the  turbine  wheel  is  specifications  recommended  by  the transmitted by the shaft  to the manufacturer  for  the  successful  overhaul generator and oil pump drive assemblies of the major components of the gas in the gearbox. turbine  engine. Due to the precision fit  of components, all tolerance a. Combustion Chamber Case specifications and torque values should Assembly. During engine operation, air be strictly followed. Long engine life is drawn in through the compressor air and efficient operation depend on the inlet,    compressed by the vanes of the care and precision with which compressor impeller, and distributed to inspections,  repairs,  and  adjustments the outer chamber of the combustion are  made. Terminology  used  in  relation chamber case. The compressed air then to general defects is defined in table passes  through  holes  in  the  combustion chamber  and  through  three  fuel  injection nozzles spaced evenly around the chamber. Fuel is atomized in the fuel (1) Note the following: injection nozzles, mixed with the compressed air,   and  injected  into  the (a) The inspection area must be combustion chamber where it is ignited thoroughly clean and the air should be by the spark igniter. Once combustion constantly  filtered. has started, the igniter is deenergized and  combustion  is  self-sustaining. (b)   The   area   must   be   well lighted. b. Turbine Assembly. The burning fuel in the combustion chamber expands (c) Cover inspection tables with rapidly and is forced through the vanes clean, dry paper. Keep  special  gages of the turbine nozzle and against the and indicators in cabinet lockers when vanes of the turbine wheel. This causes not in use. the turbine wheel to rotate. This rotary  motion is transmitted to the (d)  Openings  uncovered  during shaft which then transmits it to the inspection and repair shall be closed accessory drives located in the gearbox. with  appropriate  covers,  plugs,  or  caps. DO NOT USE TAPE. c. Gearbox Assembly. The  generator (e) Inspection limits set forth shouldered  shaft  imparts  rotary  power  to in this manual are manufacturing and the generator and oil pump drive normal wear limits. Before condemning a assemblies in the gearbox. The rotary part, check the  specifications  for power is picked up by a pinion spur gear operating limits with the mating part. that turns the output spur gear. The In many instances, mating or seating output spur gear transmits the power to surfaces for ball or roller bearings, the generator shouldered shaft and to oil seals, and friction bearings on 8-1