時間：2011-03-11 23:11來源：藍(lán)天飛行翻譯 作者：admin 點(diǎn)擊：次
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alpha control range, or alpha mode (turboprop operation). The flight operating mode for a turboprop engine from takeoff through landing. Alpha mode includes operations from 95% to 100% of the engine’s rated RPM. alpha cutoff frequency (transistor characteristic). The frequency at which the current gain (alpha) of a common-base transistor stage drops off to 0.707 of its low-frequency value. alpha hinge (helicopter rotor). The hinge at the root of a helicopter rotor blade that allows the tip of the blade to move back and forth in its plane of rotation. The axis of the alpha hinge is perpendicular to the plane of rotor rotation. An alpha hinge is also called a lead-lag hinge. alpha iron. The arrangement of the molecules in iron when its temperature is below 911°C. alphanumeric symbols. Symbols made up of all of the letters in our alphabet, numerals, punctuation marks, and certain other special symbols. alpha particle. A positively charged nuclear particle having the same mass as the nucleus of a helium atom. Alpha particles consist of two protons and two neutrons and are emitted at a high speed in certain types of radioactivity. alpha ray (electromagnetic radiation). A stream of alpha particles which ionize the gas through which they pass. These particles cause a fluorescent screen to glow. An alpha ray is made up of the lowest-frequency radio emission. alpha wave (brain waves). Electrical signals produced in the brain that have a pulse frequency of eight to 13 hertz. Alpha waves are produced by a normal human brain when in its relaxed state. alpha wave detector. A sensitive electronic device used to detect and display alpha waves from the human brain. alteration. A change to a certificated aircraft, aircraft engine, propeller, or appliance. alternate airdrome (ICAO). An aerodrome to which an aircraft may proceed when it becomes either impossible or inadvisable to proceed to or to land at the aerodrome of intended landing. alternate airport. 14 CFR Part 1: “An airport at which an aircraft may land if a landing at the intended airport becomes inadvisable.” alternate air valve (reciprocating engine induction system). A valve in the induction system of a reciprocating engine that directs air either from the air filter or from a point inside the engine nacelle into the carburetor or the fuel injection system. The alternate air valve on an engine equipped with a carburetor is called a carburetor heat valve. alternate static air valve (aircraft instrument system). A valve in the static air system that supplies reference air pressure to the altimeter, airspeed indicator, and vertical speed indicator. Normally these instruments pick up their reference air pressure from a static vent on the outside of the aircraft. If this vent ever becomes clogged with ice, the alternate static air valve can be opened, and the instruments will be supplied with static air from some unpressurized area inside the aircraft. |
