Aircraft flying faster than the speed of sound are called 'supersonic', the speed of sound at sea level is about 1225 km. per hour (765 mph). This velocity decreases with height above sea level, at an altitude of about 10500 meters, the speed of sound becomes 1060 km per hour, 1660 miles per hour. The flight of velocity greater than this velocity is called supersonic flight.
To measure the speed of aircraft flying faster than the speed of sound, it is displayed in Mach Number. The number obtained by dividing the velocity of the aircraft by the speed of sound is called the make number. If an aircraft is flying with the speed of sound, then its speed will be a make number. If that vehicle is flying with twice the speed of sound, then its speed will be two make numbers.
It is a complex task to build aircraft that move faster than the speed of sound. All the parts of high speed vehicles have to be made absolutely flat and smooth. If any part of the vehicle is bulging, then due to the high velocity, the friction of the air in the atmosphere creates a lot of heat, this heat can be so high. That could melt that part of the vehicle.
Shock wave is generated by the flights of supersonic aircraft. These are a type of pressure waves, which propagate around from the front of the flying vehicle. When these waves hit our window etc., they break the glass in them. These waves tear the eardrums. Metals like titanium and stainless steel are used in the manufacture of these vehicles:
The world's largest supersonic vehicle was Concorde, which was built jointly by Britain and France. It used to fly between London and New York to transport passengers. It used to take three hours for this journey. America and Russia have now built many supersonic aircraft for the Air Force.
