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
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
front of the first compressor rotor, and they control the angle of incidence of the inlet air, thus
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.