HYPERSONIC

Mach Number:

• Mach number (designated as M or Ma) is the ratio of the speed of the body to the speed of sound in the undisturbed medium through which the body is traveling.
  
  
• g. If the body is flying at Mach 2, then its speed is twice the speed of sound in air (which is 332 m/s or 1195 km/hr).
  
  
• It is named in honor of Ernst Mach (1838-1916), a physicist from Austria.
  
  
• Types of Aircrafts based on Mach Number (Source-NASA):
  
  

 Hypersonic Missile:

• This type of aircraft uses the shock waves generated by its own flight as a lifting surface to enhance the lift-to-drag ratio to reach Mach 5. They use a special type of jet engine called a Supersonic Combustion Ramjet (Scramjet)
  
  
• The recent hypersonic missile developed by Russia could fly at Mach 20 and manoeuvre up and down, meaning that it could breach defence systems.