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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blending (turbine engine maintenance). A method of repairing damaged compressor and turbine blades. The damage is removed and the area is cleaned out with a fine file to form a shallow depression with generous radii. The file marks are then removed with a fine abrasive stone so the surface of the repaired area will match the surface of the rest of the blade. blimp. The name given to a cigar-shaped, nonrigid airship. Nonrigid airships were originally called limp airships. blind flight. A term used in the early days of aviation to refer to flight by reference to instruments when the natural horizon is not visible. The term blind flight has been replaced by the more accurate term instrument flight. blind rivet. A special rivet used in a sheet metal structure that can be installed when there is access to only one side of the metal. The most widely used type of blind rivet has the end of its hollow shank upset by pulling a tapered plug up into the shank. blind speed (air traffic control). The rate of departure or closing of a target relative to the radar antenna at which the cancellation of the primary radar target by moving target indicator (MTI) circuits in the radar equipment causes a reduction or complete loss of signal. blind spot (radio operation). An area from which radio transmissions and/or radar echoes cannot be received. blind spot (visual operation). An area on an airport not visible from the control tower. blind velocity (ICAO). The radial velocity of a moving target, such that the target is not seen on primary radars fitted with certain forms of fixed echo suppression. blink Zyglo. A form of nondestructive inspection of parts subject to vibration. In this method of inspection, the part is cleaned and soaked with a fluorescent penetrant for an appropriate length of time. Then the part is rinsed, and all the penetrant is cleaned from its surface. The part is vibrated while it is being examined under a black light. If the vibration opens up a crack that has accepted some of the penetrant, the crack will show up as a blinking light. blip (radar indication). A spot of light on a radar scope caused by a received signal, or a return from a reflecting object. Blips are also called echoes. blisk (turbine engine component). A turbine stage machined from a single slab of steel. The disk and blades are an integral unit. blister (evidence of corrosion). A raised spot on a piece of metal that contains the salts of corrosion. Corrosion forms under the surface of the metal, and since its salts have so much more volume than the metal they displace, the surface layer of metal is pushed out to form the blister. blizzard (meteorology). Severe weather conditions characterized by low temperatures and strong winds bearing a great amount of snow, either falling or picked up from the ground. block diagram. A functional diagram of a system in which the units are represented by blocks that describe the functions of the unit and show its relationship to the other units of the system. Arrows between the blocks show the direction of flow of energy or information within the system. Block diagrams do not show any of the actual components. |
