時間：2011-03-11 23:11來源：藍天飛行翻譯 作者：admin 點擊：次
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bearing race. The hardened steel surface upon which the balls or rollers of an antifriction bearing ride. bearing rollers. Hardened steel rollers that support a rotating shaft. The rollers ride between two hardened steel races and are usually spaced evenly around the races by a thin sheet metal separator. bearing strength (sheet metal specification). The amount of pull needed to cause a piece of sheet metal to tear at the points it is held together with rivets. The bearing strength of a material is affected by both its thickness and the diameter of the rivet. bearing support (gas turbine engine component). The portion of the case of a gas turbine engine in which the main bearings are mounted. bearing surface. A surface which supports a moving load. Bearing surfaces are normally treated in some way to decrease the friction between the surface and the load being moved. beat (vibration). A low-frequency sound, or vibration, produced when two sources of vibration having almost, but not exactly, the same frequency, act on an object at the same time. For example, in a multi-engine airplane, if one engine is turning at 1,850 RPM and the other is turning at 1,880 RPM, the airframe vibrations caused by these engines will produce a very noticeable beat of 30 cycles per minute. This beat is caused by the difference in the frequency of the two vibrations. beat frequency. The frequency of vibration produced when two sources of vibration act on a common body. The beat frequency is the difference between the frequencies of the two original vibrations. Beaufort scale. A number rating from zero to 12, used by the weather bureau to describe wind speed. Beaufort Velocity Force (knots) Indication 0 less than 1 smoke rises vertically 1 1 – 3 wind blows smoke 2 2 – 7 wind felt on face 3 8 – 12 leaves in motion |
