時間：2011-03-11 23:13來源：藍天飛行翻譯 作者：admin 點擊：次
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life-limited part. An aircraft part whose service life is limited to a specified number of operating hours or operating cycles. life-support systems. Systems in an aircraft which make it possible for the occupants to operate in an environment that does not support life. Oxygen systems and pressurization systems are examples of life-support systems. lift (aerodynamic force). An aerodynamic force caused by air flowing over a specially shaped surface called an airfoil. The airfoil is curved in such a way that the air flowing over the upper surface finds the surface falling away from it. The air is being pressed onto the surface by the air above it, and in order for it to remain on the surface, it must speed up. As the air speeds up, its pressure drops, and the air above it flows down to fill the low-pressure area. The air below the airfoil finds the surface rising into its flow path, and this slows the air. As the air slows down, its pressure rises, and it forces the surrounding air away from it. The combination of the low pressure pulling air down to the airfoil and the high pressure forcing air away from the airfoil causes the air to be deflected downward. When an airfoil forces air downward, a force equal to the weight of the deflected air forces the airfoil upward. This force is called lift. lift coefficient (aerodynamic parameter). A dimensionless number used in the formula for aerodynamic lift that varies with the shape of the airfoil and the angle of attack. The lift coefficient (CL) is obtained from |
