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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iron-vane meter movement (AC ammeter). The mechanism in an AC ammeter whose pointer is attached to a soft iron vane and restrained by a calibrated hairspring. The vane is rotated by the magnetic field produced by the unknown current flowing through a surrounding coil. The greater the current, the stronger the magnetic field and the greater the pointer deflection. irreversible controls (aircraft controls). Controls in an aircraft operated by a boost system. Cockpit controls move the control surfaces, but aerodynamic forces on the control surfaces cannot feed back into the cockpit controls. isobar (meteorology). A line on a weather map that shows equal or constant barometric pressure. isobaric range of cabin pressurization. The range of cabin pressurization in which cabin pressure is maintained at a constant level (a constant cabin altitude), rather than allowing it to change with flight altitude. Most cabin pressurization systems operate in the isobaric range up to the altitude at which the cabin differential pressure is the maximum allowed by the aircraft structure. Then the system automatically shifts to the constant-differential mode, which keeps a constant pressure difference between the pressure of the air inside the cabin and the air outside the cabin. isoecho (radar meteorology). A circuit in a weather radar that reverses signal strength above a specified intensity level. An iso echo circuit causes a void on the scope in the most intense portion of an echo when the maximum intensity is greater than the specified level. isogonic lines. Lines drawn across aeronautical navigational charts that connect points having the same magnetic variation. Isogonic means “the same angle.” isoheight (meteorology). A line on a weather chart showing equal height. An isoheight is the same as a contour. isolation mount (shock-absorbing engine mount). A type of mount that supports the engine on steel-backed rubber pads. These pads isolate the engine from the airframe and prevent vibrations damaging the structure. isolation transformer (electrical component). An electrical transformer used to isolate a piece of electrical equipment from the power line. An isolation transformer has the same number of turns in its secondary winding as it has in its primary. This one-to-one turns ratio causes the output voltage and current to be the same as that of the input. An isolation transformer electrically isolates equipment connected to its secondary winding from the power line. This isolation prevents the danger of electrical shock when working on the equipment. isoline (meteorology). A line on a chart showing an equal value of a variable quantity. Weather maps use isobars (lines of equal pressure), isotherms (lines of equal temperature), isoshears (lines of equal wind shear), and isotachs (lines of equal, or constant, wind speed). isometric drawing. A drawing made in such a way that it has no visual perspective. Equal distances on the object are equal distances on the drawing. |
