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Show : '1 PLANE : T ; TALK 1 Rowland Burnstan 1 E ' One of the instruments which plays an important part in air tliti'ht is the air speed indicator, ivhich tells the airplane's speed in. Ili-lit in relation to the air through which it is living. Ground speed, however, is the speed of the air-, air-, plane in relation to the ground, and is not indicated by this instrument, , but can he computed from the readings. read-ings. In still air, air speed equals ' ground speed. In a head wind, the ground speed is less than airspeed, ' and with a tail wind the ground speed is greater than ail' speed. Hy adding or subtracting the velocity velo-city of the wind, the ground speed is determined. VS. 180 6 120 CV V, 159 140 SJ , There are maximum and minimum mini-mum air speeds between which an I airplane can he safely operated. If a pilot peimits his plane to go below be-low the minimum indicated air speed or stalling speed, the plane tends to become unmanageable. Diving the airplane beyond the rated rat-ed maximum speed takes it beyond the safe limits from a construction viewpoint. i In addition to its use as a safety safe-ty instrument, the airspeed indicator indi-cator aids in navigation. It is also possible for the pilot to tell from any indicated change in speed if the plane is not in level flight during poor flying weather.'" |