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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longitudinal wave. Waves within an elastic material in which the particles in motion move back and forth, parallel to the direction the wave is traveling. long-range communication system. A system that uses satellite relay, data link, high frequency, or other approved communication system which extends beyond line of sight. long-range navigation system. An electronic navigation system that is approved for use under instrument flight rules as a primary means of navigation and has at least one source of navigation input, such as inertial navigation system, global positioning system, Omega/very low frequency, or LORAN C. loom (electrical wiring). A type of flexible, braided insulating material put over a wire or a bundle of wires to protect it against physical damage caused by heat or abrasion. loop (aircraft maneuver). A flight maneuver in the vertical plane in which an airplane passes successively through a climb, inverted flight, dive, and then returns to normal flight. loop (electrical circuit). A complete path in an electrical circuit through which current flows from one terminal of the power source back to the opposite terminal. loop antenna (radio direction finding). A type of directional antenna, used with radio direction finding equipment to determine the direction to the station transmitting the signal the loop is receiving. Loop antennas must be used with a sense antenna to show the side of the loop on which the transmitting antenna is located. loopstick antenna. A type of radio antenna made of a number of turns of wire wound around a rod of powdered iron. The powdered iron increases the permeability of the core of the coil and increases the radio signal picked up by the coil. LORAN (electronic navigation system). A type of electronic navigation system, used by aircraft and ships. The name LORAN comes from LOng RAnge Navigation. LORAN is a low-frequency pulse navigation system based on latitude and longitude coordinates. A master station transmits a pulse of energy that is received by the aircraft and by two or more slave stations. As soon as the slave stations receive the pulse, they transmit a pulse of their own, and these pulses are also received in the aircraft. The computer in the LORAN receiver measures the difference in time the signals from the master station and from each slave station were received. For every time difference, there is a line, called a line of position (LOP), along which the aircraft is located. The computer determines the lines of position and displays the latitude and longitude of the aircraft. The pilot can enter the latitude and longitude of the destination airport or of waypoints along the way, and the LORAN will display the bearing to the location, the distance to that point, and the ground speed of the aircraft, and estimated time of arrival (ETA) at the point. LORAN A. A LORAN system that operates with frequencies of 1,950 kHz, 1,850 kHz, and 1,900 kHz. LORAN C. The LORAN system used in aircraft. It operates on a frequency of 100 kHz. |
