What is Mach Number ? History and The importance of Mach
What is Mach?
Mach, sometimes also referred to as a Mach number, is a speed measurement based on the speed of sound. Since sound travels at different speeds in different conditions, the calculations here are given for 20°C in dry air at sea level.
Mach, Ma, M
Mach can be abbreviated as M, and is also sometimes abbreviated as Ma. For example, Mach 1 can be written as 1 M or 1 Ma.
Although Mach can be abbreviated M or Ma, the Mach number is typically expressed with the number after the unit name. For example, the expression Mach 3 is preferred rather than 3 Machs or 3 M.
The speed is classified as either subsonic, transonic, supersonic, or hypersonic depending on the Mach number.
The Mach number is named after Moravian physicist and philosopher Ernst Mach, and is a designation proposed by aeronautical engineer Jakob Ackeret in 1929.
The importance of Mach
Mach is typically used in aviation and space exploration.
Mach 1 is traveling at the speed of sound; Mach 2, twice the speed of sound, and so on. In dry air at 0°C, the speed of sound is 1,193.3 kilometers per hour (741.5 miles per hour).
Only military aircraft are permitted to reach Mach 1 over the United States. The British-French Concorde airliner did reach supersonic speeds on its transoceanic flights, and had a Mach meter on the forward bulkhead of its passenger cabin.
Flight can be roughly classified in six categories:
|Speed of sound
|0.8 – 1.2