时间：2011-03-11 23:13来源：蓝天飞行翻译 作者：admin 点击：次
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ductility (metal characteristic). The property of a material that allows it to be drawn into a thin section without breaking. Because copper has a great deal of ductility, it is possible to draw it into very fine wires. duct losses (gas turbine engine losses). A decrease in pressure of the air flowing into a gas turbine engine caused by friction. dummy load. A noninductive, high-power resistor that can be connected to a transmission line in place of the antenna. The transmitter can be operated into the dummy load without transmitting any signal. dump chute (aircraft fuel system component). A specially shaped duct, or tube, used to carry fuel away from the aircraft when it is dumped from the fuel tanks. Some large aircraft are permitted to take off with a greater weight than they are allowed to have when they land. However, if such an aircraft must make an emergency landing before it has burned off enough fuel to reduce its weight to its legal landing weight, it must dump enough fuel to get rid of this excess weight. The dump chute is designed to carry the fuel away from the aircraft so it will not be ignited by the engine exhaust or by static electricity. duo-servo brakes (type of aircraft shoe brakes). A form of shoe brake that uses the weight of the aircraft to wedge the shoes tightly against the drum when the aircraft is rolling either forward or backward. duplex fuel nozzle (gas turbine engine component). A type of fuel nozzle that discharges its fuel into the combustor, or burner, at two different rates and flow patterns; one for low airflow and the other for high airflow. These flow patterns determine the shape of the flame inside the burner and both flow patterns keep the flame centered in the burner so it will not touch the thin metal of which the burner is made. duplex operation (electronic communications). A method of communications in which each end can simultaneously transmit and receive. Communication by telephone is duplex operation. Duplex operation by radiotelephone requires the use of two frequencies. durability. A measure of engine life. Durability is normally measured in hours of time between overhauls, or TBO. duralumin. The trade name for one of the original alloys of aluminum, magnesium, manganese, and copper. Duralumin, which is the same as modern 2017 aluminum alloy, was first used by the Germans to build the Zeppelins of World War I. The term dural, which was at one time used for almost all the high-strength aluminum alloys, was taken from the name duralumin. dust (meteorology). Fine particles of dry matter suspended in the atmosphere. dust devil (meteorology). A small, vigorous whirlwind, usually of short duration. Dust devils are made visible by dust, sand, and debris picked up from the ground. dust storm (meteorology). An unusual, frequently severe weather condition in which strong winds and dust-filled air cover an extensive area. Dutchman shears (mechanic’s hand tool). A common name for compound-action sheet metal shears. Dutchman shears come in three types: those that cut straight, those that cut to the right, and those that cut to the left. |
