Читать книгу Flight Theory and Aerodynamics - Joseph R. Badick - Страница 71

The Mach number is found by comparing TAS to the speed of sound for a given set of conditions at a specific altitude. The speed of sound is an important factor in the study of high‐speed flight and is discussed in depth in Chapter 14. Because the aircraft’s speed in relation to the speed of sound is so important in high‐speed flight, airspeeds are usually measured as Mach number (named after the Austrian physicist Ernst Mach). Mach number is the aircraft’s true airspeed divided by the speed of sound (in the same atmospheric conditions):

(2.13)

where

 M = Mach number

 V = true airspeed (kts.)

 a = local speed of sound (kts.)