What is the measurement used when a plane is said to travel at hypersonic? How does the air act at the nose of the plane? Would the nose and wing have to be razor sharp to cut the air? because the nose of the space shuttle seems blunt.

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    $\begingroup$ "ultra-sonic" is not a speed, but rather a frequency. It refers to sound waves at a frequency higher than what humans can hear. Perhaps you're thinking of hypersonic? $\endgroup$
    – reirab
    Jan 23, 2017 at 1:50
  • $\begingroup$ @reirab thank you for correcting that. $\endgroup$
    – user20435
    Jan 23, 2017 at 1:52
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    $\begingroup$ Perhaps some simple research would help before asking. This Wikipedia article contains all the answers to your questions. $\endgroup$
    – mins
    Jan 23, 2017 at 3:13
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    $\begingroup$ Hypersonic means Mach 5 and above. All other questions can be answered by looking around here. $\endgroup$ Jan 23, 2017 at 7:33

1 Answer 1


Hypersonic flight is generally any speeds between Mach 5 to Mach 10. Although we set a speed delineation for the boundary between supersonic and hypersonic flows, the real boundary is where simple compressible flow aerodynamics using Mach and Reynolds numbers are no longer adequate to models the flow and multiple relationships between fluid mechanics, thermodynamics and heat transfer come into play.