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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Neither the 200 series nor the 300 series of stainless steel can be hardened by heat treatment, and the steel in both of these series is nonmagnetic. The 400 series of stainless steel which can be hardened by heat treatment and is magnetic is used for knife blades and razor blades. staking. A method of securing a part in a recess in a metal surface. For example, a disk can be fastened in a counterbored hole by staking the edges of the hole. The disk is put into the hole, and a pointed staking tool is held near the edge of the hole and hit with a hammer. The staking tool forces metal from the edge of the hole over the disk to prevent its from coming out of the hole. stall (aerodynamic condition). An aerodynamic condition in which the angle of attack, the angle at which the relative wind strikes the airfoil, becomes so steep the air can no longer flow smoothly over the airfoil. When an airfoil stalls, it stops producing lift. stalled-rotor torque (electric motor characteristic). The amount of torque produced by the rotor of an electric motor when it is fully energized with the correct voltage, but the rotor is held so it cannot turn. stall strip (airplane wing component). A small triangular metal strip installed along the leading edge of an airplane wing near the root. Many airplane wings begin to stall near the tip, in the area ahead of the ailerons. When this portion of the wing stalls, the pilot no longer has good control of the aircraft. To allow adequate control throughout the stall, the small stall strips force the roots of the wing to stall before the tips. When the wing roots stall, the nose of the aircraft drops, and the aircraft recovers from the stall with complete control throughout. stall warning system (aircraft flight instrument). A system that warns the pilot when the angle of attack of the wing reaches a point that will likely produce a stall. Stall warning systems measure the angle of attack. Some systems use a small air-operated vane on the leading edge of the wing to detect the high angle of attack. Others use an angle of attack probe on the fuselage. A few of the smaller airplanes have a reed-type horn in the wing that changes its sound as the angle of attack changes. Some stall warning systems turn on a light or sound a warning horn when the angle of attack gets too near the angle that could cause a stall. Some of the more elaborate systems, called stick shakers, vibrate the control column, and stick pushers actually push the control column forward when a stall is approached. standard atmosphere. 14 CFR Part 1: “The atmosphere defined in the U.S. Standard Atmosphere, 1962 (Geopotential altitude tables).” standard atmospheric conditions. Conditions of the atmosphere that have been agreed upon by scientists and engineers who work with the atmosphere to allow them to correct all measurements to the same conditions. standard cell (electrical voltage standard). A cadmium-mercury cell made in a specially shaped glass container in which the two electrodes are covered with an electrolyte of cadmium sulfate. The voltage produced by a standard cell is 1.018636 volts at 20°C. A standard cell is also called a Weston standard cell or a Weston normal cell. |
