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 out-put 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
Fuel pressure indicating system -- device that gives continuous readings in psi of fuel pressure in the
main fuel supply line.
Gas producer (N1) -- compressor in a free-power turbine engine.
Gas turbine engine -- aircraft powerplant that is adaptable for both airplanes and helicopters.
Gerotor pump -- modified gear-type pump with two moving parts, an inner toothed element and an outer
toothed element. The inner one has one less tooth than the outer.
Glow plug -- device that consists of a heating element in a short conventional-looking spark plug.