时间：2011-03-11 23:18来源：蓝天飞行翻译 作者：航空 点击：次
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turpentine. A liquid obtained by distilling the gum from pine trees. Turpentine is used as a solvent and thinner for paints and varnishes. turret lathe. A type of metal-turning lathe in which the cutting tools are mounted in a turret. For example, a drill, a boring tool, and a chamfering tool can be mounted in the turret. The drill is moved into the work to drill the hole. The drill is then backed out, the turret is rotated to put the boring tool in place, and the hole is counterbored. The boring tool is then backed out and the chamfering tool is rotated into place. The chamfering tool is moved into the work to chamfer the edges of the counterbored hole. twelve-point socket (mechanic’s hand tool). A socket wrench with a double hex, or a 12-point, opening broached into its open end. A 12-point socket is easier to position on a nut or bolt head than a six-point socket. twenty-minute rating (battery capacity rating). The ampere hour rating of an aircraft battery when the current drawn from it will drop its voltage to a predetermined cut-off voltage in twenty minutes. twilight. The intervals of incomplete darkness following sunset and just preceding sunrise. The time at which evening twilight ends and morning twilight begins is determined by arbitrary convention. See civil twilight, nautical twilight, astronomical twilight. twin-row radial engine (reciprocating engine type). A type of radial engine with two rows of cylinders and a single crankshaft. The cylinders of a radial engine project out from a small crankcase that holds the crankshaft. The piston in one cylinder attaches to a master rod whose large end goes around the crankshaft throw, and the pistons in all of the other cylinders attach to the master rod with link rods. A twin-row radial engine has a two-throw crankshaft and two rows of cylinders and two master rods. The cylinders in the rear row are staggered between those in the front row for improved cooling. The most popular twin-row radial engines have 14 or 18 cylinders. twist drill. A metal-cutting tool turned in a drill press or a hand-held drill motor. A twist drill has a straight shank and spiraled flutes. A cutting edge is ground on the end of the spiraled flutes. The diameter of twist drills is measured in four different ways: Fractions of an inch, millimeters, letters, and numbers. twisted pair (electrical cable). A type of electrical cable made up of two insulated wires twisted together and enclosed in an outer insulation. The magnetic fields caused by current flowing in the two conductors of a twisted pair cancel each other and minimize the magnetic field radiating from the conductors. twister (meteorology). A colloquial term for tornado. twist stripe (flexible fluid lines). A colored stripe running along the length of a flexible hose. If this stripe spirals around the hose, it indicates that the hose was twisted when it was installed. Twist stripes are also called lay lines. two-axis automatic pilot. An automatic pilot that uses a canted rate gyro, similar to that used in a turn coordinator, to sense rotation of the aircraft about its longitudinal and vertical axes. Output from the rate gyro controls a pair of servos in the aileron system that keeps the wings level and the airplane stable in roll and yaw. Two-axis automatic pilots are sometimes called wing levelers. |
