Identify the location of the components in the combustion section and state their purpose.
Outer Case and Inner Liner: Provides thermal separation from the combustion chamber and the exterior of the combustor section. Also provides a flow path for cooling air from the Air Transfer tubes.
State the purpose of air flow through the compressor and amount used for each purpose.
75% for cooling, 25% for combustion
State the purpose of the turbine section in the 250C – 20J engine.
Converts heat energy to mechanical energy
Identify the components of the turbine section and state their function.
2 stage Gas Producer Turbine: Drives the compressor and Ng gear train.
2 stage Free / Power Turbine: Drives the Nf gear train.
Thermocouple Assembly: 4 thermocouples provide signal to TOT gauge
State what portion of the available energy is used to drive the gas producer and free power turbine sections.
2/3’s Compressor and Ng drive train(51,989 rpm at 100%)
1/3 Nf drive train(33,956 rpm at 100%)
Identify the location and name of the components used for measuring turbine outlet temperature (TOT).
System Requires 28v DC
4 TOT thermocouples between the Ng and Nf turbines
TOT indicator circuit breaker
TOT Light (Comes on when START limits are exceeded. Maintenance must reset with a key in the battery compartment)
Identify the functions of accessory gear box.
Primary structural member for the engine. Provides mount for compressor and turbine sections and 4 engine mounts (3 used to mount the engine, 4th used to mount the anti-ice motor)
Identify the accessories driven by the gas producer.
ach generator (Ng)
il Pump (Shares the same shaft as the Ng Tach)
uel Control Unit
Identify the units driven by the power turbine gear train.