M
This parameter represents Mach number. Mach number is defined as the ratio of the local true airspeed to the local speed of sound. It is a measure of how fast the air is moving relative to the speed of sound in that air. If the air (or an object through stationary air) is moving at Mach = 0.90, then it is moving at 90% of the local speed of sound. Some people over simplify Mach number by assuming that the speed of sound is a constant, but actually, the speed of sound is a function of air temperature, so it varies with altitude.
The following methods are used by this program to calculate Mach number:
Where is the speed of sound at sea level and
is the specific heat ratio for air (=1.4).
Modified: October 13, 2003