HIGH SPEED FLIGHT

Subsonic – All flow everywhere on the aircraft is less than the speed of sound.

Transonic – Some flow is subsonic and some is supersonic.

Supersonic – All flow everywhere on the aircraft is supersonic.

In addition to these speed ranges future aircraft will need to recognize a Hypersonic speed range which begins at approximately Mach 5. In this speed range the air is heated so much by the friction of the aircraft passing through it that the air molecules ionize. This disrupts radio communications and is the main reason space agencies loose contact with space craft for several minutes when they first enter the atmosphere on return from space.

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