Heat exchanger -- fuel-oil cooler, to help cool the oil. The exchanger is a cylindrical oil chamber
surrounded by a jacket through which the fuel passes. Heat from the oil is transferred to the
fuel by conduction.
Humidity -- amount or degree of moisture in the air. If humidity increases, air density is decreased.
Humidity has little effect on density, however, in comparison with temperature and pressure
Igniter plugs -- spark plugs which function only during starting and cut out of the circuit as soon as
Imbalance -- uneven distribution of weight resulting in rotating parts being out of balance. Measured in
inch-grams or inch-ounces.
Impeller rotor -- rotor in a compressor that revolves at high speed, drawing air into the blades.
Inlet guide vanes -- devices positioned by the inlet guide vane actuator pilot valve. They are located in
ensuring a compressor surge margin.
Inlet housing assembly -- forward structural support of the engine.
Jetcal analyzer -- device used to check the exhaust gas temperature during periodic maintenance
inspections or when abnormally high or low temperatures are noted.
Jet propulsion -- propulsion of a body by means of a jet or stream of gas, obtaining all or most if its
thrust by reaction to the ejection of the combustion products (gas).
Joule -- unit of energy or work used in rating gas turbine ignition systems. A joule is equal to the
amount of energy expended in one second by an electric current of one ampere through a
Kinetic energy -- work energy associated with motion.
Labyrinth seal -- device for preventing leakage of gas on the gas generator shaft in a turbine. A
labyrinth consists of a series of projections on the rotating element running in close contact with
grooves on the stationary element.