时间：2011-03-11 23:13来源：蓝天飞行翻译 作者：admin 点击：次
|
eductor. A form of jet pump used to pick up one liquid and mix it with another. Eductors are used in some aircraft fuel systems to remove fuel from a vent-drain tank and return it to the main tank. Fuel from the boost pump flowing through the eductor produces a low pressure that pulls fuel from the vent-drain tank and carries it back into the main tank. EEC (electronic engine control). An electronic fuel control for a gas turbine engine. The EEC senses the power-lever angle (PLA), engine RPM, bleed valve, and variable stator vane position, and the various engine pressures and temperatures. It meters the correct amount of fuel to the nozzles for all flight conditions to prevent turbine overspeed and overtemperature. effective pitch (propeller parameter). The actual distance a propeller moves through the air in one revolution. Effective pitch is the difference between the geometric pitch of the propeller and the slip. See geometric pitch, and slip. effective value (AC electricity). The value of sine wave alternating current needed to produce the same amount of heat as this value of direct current. The effective value of sine wave AC is 0.707 time its peak value. This means that AC having a peak value of one amp will produce as much heat as , or 0.707 amp of direct current. Effective value, also called root mean square, or rms, value of alternating current is found by: (1) squaring all the instantaneous values of the current or voltage in one alternation; then (2) averaging these values; and then (3) finding the square root of this average. Most AC voltmeters are calibrated to show the effective value of the voltage they measure. efficiency. A measure of the effectiveness of a system or device. Efficiency is found by dividing the output of the device by its input, and it is usually expressed as a percentage. If the output of a device is exactly the same as its input, the device has an efficiency of 100%. If its output is only one half of its input, its efficiency is 50%. EFIS (electronic flight instrument system). A complete electronic flight instrumentation system that includes the EICAS (engine indicating and crew alerting system) and the ECAM (electronic centralized monitoring) system. See EICAS and ECAM. E-gap angle (magneto measurement). The position of the rotating magnet in a magneto when the breaker points are timed to open. The E-gap (efficiency gap) angle is several degrees of magnet rotation beyond the magnet’s neutral position. At this point the magnetic field stress is the greatest, and the change in flux is the greatest, inducing the maximum voltage in the secondary winding. EGT (exhaust gas temperature). The temperature of the gases as they leave the cylinder of a reciprocating engine or the turbine of a gas turbine engine. EGT indicating system (gas turbine engine). An indicating system used with a gas turbine engine to measure the temperature of the exhaust gases as they enter the tail pipe, after passing through the turbine. The turbine inlet, a point just before the exhaust gases enter the turbine, is the most critical location inside a gas turbine engine with regard to temperature. But it is very difficult to measure the temperature at this location. |
