Engine surge --  result of compressor stall. The complete engine in stall.  Exhaust --  hot gases discharged from the engine through the exhaust diffuser section.   Exhaust diffuser --  section composed of an inner and outer housing, separated by hollow struts across the exhaust passage. It forms a divergent flow path for the exhaust gases.   Exhaust gas temperature indicator --  sensitive millivoltmeter calibrated in degree centigrade, activated by an electrical force generated by its thermocouple. 
 

 
 
飞机发动机术语英文解释（F）
 

Feedback --  relay through the controls of aerodynamic forces exerted on the control surfaces and felt by the pilot.   Fir tree mount --  manner of attaching the blades to the disk in the turbine rotor assembly. The root of the blade where it is attached to the disk is shaped like a fir tree.   Foreign object --  any object such as a tool, piece of equipment, engine part (nut, bolt, lockwire) that could in any way damage the engine.   Foreign object damage --  commonly called FOD, harm or destruction to the turbine engine caused by foreign objects sucked into the inlet area of the engine with the required air.   Forged --  shaped by hammering. Only the malleable metals are worked successfully. The application of heat increases plasticity.   Free-power turbine engine --  the turbine engine used by the Army. Sixty percent of the energy produced by combustion is extracted by the gas producer turbine to drive the gas producer rotor. The rest of the energy is converted to shaft horsepower to drive the output shaft of the engine. 
 

 Frictional loss --  resistance to the relative motion of air flowing along a duct.   Frontal area --  front part of a gas turbine engine, smaller than that of a reciprocating engine, therefore producing less drag.   Front of engine --  end from which power is extracted. An exception is the T73 engine on the CH-54, in which the power is extracted at the end where the exhaust gas is expelled.   Fuel-air ratio --  see air-fuel ratio.   Fuel atomizer --  see atomizer.   Fuel controls --  devices to control fuel flow. They are usually hydromechanical and include speed governors, servo systems, valves, metering systems, and sensing pickups.   Fuel divider --  device that meters fuel to the engine nozzles according to a predetermined schedule of secondary flow versus primary flow.   Fuel nozzle --  device to inject fuel into the combustion chamber in a highly atomized and accurately shaped spray.   Fuel pressure indicating system --  device that gives continuous readings in psi of fuel pressure in the main fuel supply line.