時(shí)間：2011-03-11 23:13來源：藍(lán)天飛行翻譯 作者：admin 點(diǎn)擊：次
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Hot spark plugs are used in low-powered engines because a cold spark plug would not get hot enough to burn the contaminants out of its firing-end cavity. If these contaminants are not burned out, they will foul the spark plug and prevent it from firing properly. hot stamping. A method of marking plastic materials, cloth, or paper by using heated metal dies. The heated dies force molten metal leaf (extremely thin sheets of metal) into the surface of the material. hot start (gas turbine engine). A condition in which a gas turbine engine starts, but its internal temperature rises high enough to damage the engine. Any time an engine has a hot start, it must be given a special inspection to determine if any damage has been done. hot streaking (turbine engine malfunction). A hot section malfunction in which the flame penetrates through the entire turbine system and into the tail pipe. hot-tank lubrication system (gas turbine engine). A lubrication system of a gas turbine engine in which the oil cooler is in the pressure portion of the system. Hot oil returns directly from the engine into the tank without being cooled. hot valve clearance (radial reciprocating engine specification). The clearance between the valve stem and the rocker arm of a radial engine when the engine is operating at its normal temperature. The hot, or running, clearance is much greater than the cold clearance, and it is measured only when adjusting the valve timing. After the timing is properly adjusted, using the hot clearance, all of the valves are set to the much smaller cold clearance. hot wire. The common term used for a wire connected to the source of electrical power. hot-wire ammeter. An ammeter used for measuring high-frequency alternating current. The current flows through a fine wire held under a slight tension, and the heat produced by the current causes the wire to expand and increase its length. As the wire lengthens, it moves a pointer across the dial to show the amount of current flowing through the wire. hot-wire anemometer. A form of wind-speed indicator in which the wind whose speed being measured passes over a wire heated by an electrical current. The amount of heat the moving air removes from the wire is proportional to the wind speed. hot-wire cutter. A cutter used to shape blocks of Styrofoam. The wire is stretched tight between the arms of a frame and heated by electrical current. The hot wire melts its way through the foam. hourmeter (aircraft instrument). An instrument installed in many aircraft to show the actual number of hours the engine has operated. The hourmeter is an electrical clock that starts when the engine oil pressure builds up, and runs until the engine is shut down and the oil pressure drops to zero. hover (helicopter operation). A condition of helicopter flight in which the machine holds a fixed position over the earth. When a helicopter is hovering, it is not moving in any direction relative to the terrain below it. |
