Subsonic can describe any flight slower than the speed of sound. It can also describe flight slower than the transonic region. The borders of the transonic region are defined at the lower end where any part of the airflow around the airfoil becomes supersonic and at the upper end where all airflow around the airfoil is supersonic.
|Quoting Arzouni (Thread starter):|
b. and Describe three design features that can be used to delay the problems of
Transonic Flight and how the features achieve the delay ?
1. Swept wings. Delay the onset of shockwaves. Shockwaves depend on the span component that is perpendicular to the trailing edge, and this is a smaller component than actual airspeed on a swept wing.
2. Supercritical airfoils. Delay the onset of shockwaves.
3. Mach trimmers. Automatically trim out mach tuch.
I recommend the old but excellent "Handling the big jets" for information, but warn that it was written before supercritical airfoils.
[Edited 2012-08-04 05:28:53]
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