时间：2011-03-11 23:11来源：蓝天飞行翻译 作者：admin 点击：次
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“Blocked” (air traffic control communications). The phrase used to indicate that a radio transmission has been distorted or interrupted due to multiple simultaneous radio transmissions. block heater (sheet metalworking tool). An electrical heater embedded in the die used for hot dimpling sheet metal. blocking capacitor (electronic circuit component). A capacitor having a high impedance to DC and low-frequency AC, but a low impedance, or a small opposition, to the AC signal being passed through the circuit. block plane. A small hand-held woodcutting tool used for cutting across the grain of wood and for planing the ends of a board to make them smooth. block test (aircraft engine test). An operational test of an aircraft engine installed in a test cell. Block tests are used to determine the condition of the engine. block-to-block time (aircraft records). The amount of elapsed time between an aircraft leaving the departure ramp for the purpose of flight and its reaching the arrival ramp at the end of the flight. bloom (metal processing). A semifinished mass of steel formed from an ingot in the process of being rolled into a billet. blow-in doors. Spring-loaded doors in the inlet duct of some turbojet or turbofan engine installations that are opened by an air pressure differential when the inlet air pressure becomes a certain amount lower than that of the ambient air. Air flowing through the doors adds to the normal inlet air passing through the engine and helps prevent compressor stall. blow molding. A form of plastic molding in which a hollow tube of thermoplastic material is heated inside a mold. Air pressure is applied to the inside of the tube, and the soft plastic material is forced out against the walls of the mold. The outside of the part takes the form of the inside of the mold. The mold is then opened and the molded part removed. blow-by (reciprocating engine malfunction). The loss of pressure in the engine cylinder caused by leakage past the piston rings. blow-down turbine (reciprocating engine component). A power-recovery device used in the exhaust system of a reciprocating engine. A blow-down turbine is a velocity-type turbine driven by the exhaust gases from the engine and coupled through a fluid coupling to the engine crankshaft. Blow-down turbines are also called power-recovery turbines, or PRTs. blower (reciprocating engine component). An internal gear-driven supercharger in an aircraft reciprocating engine. Blowers increase the pressure of the air after it passes through the carburetor and improve the uniformity of the distribution of the fuel-air mixture to all the cylinders. blower section (reciprocating engine crankcase section). The section of an aircraft reciprocating engine crankcase that houses the internal, gear-driven supercharger. blower. A mechanical device, such as a fan, used to move a volume of air. blowing dust (meteorology). Dust particles picked up locally from the surface and blown about in clouds or sheets. |
