In flight mechanics and aviation, the “Flight Mach Number” is a dimensionless parameter used to express an aircraft’s speed relative to the speed of sound in the surrounding air. It is a critical parameter in high-speed flight and is denoted by the symbol “M.”
The Flight Mach Number is defined as the ratio of the true airspeed (V) of the aircraft to the speed of sound (a) in the same air mass:
M = V / a
where:
- M: Flight Mach Number
- V: True Airspeed of the aircraft (actual speed through the surrounding air)
- a: Speed of Sound in the air mass surrounding the aircraft