更快、更高、更远人类飞天总在不断追求着更快、更高、更远的目标。对飞机而言,衡量性能的好坏主要有三项指标,即速度、升限和航程,其中又以“快”字当头。“速度”主要指最大平飞速度。飞机经常做的是水平飞行,其最大速度在作战或运输中具代表意义。当飞机在某一高度作水平等速飞行时,阻力和推力(或拉力,由发动机产生)正好平衡,飞机依 Faster, Higher and Farther Human beings are always pursuing faster, higher and longer goals. For aircraft, there are three main indicators to measure the performance: speed, ceiling and range. Among them, the word “fast” is used. “Speed ​​” mainly refers to the maximum flat flying speed. Planes often do horizontal flights, the maximum speed of which is of significance in combat or transport. When the aircraft is flying at a constant horizontal speed at a certain altitude, the drag and thrust (or pull, generated by the engine) are exactly balanced and the aircraft