Re: Stalls

From: (Robert Dorsett)
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
Date:         24 Apr 94 22:23:43 
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In article <airliners.1994.1164@ohare.Chicago.COM> (Kyle D. Jackson) writes:
>I had the understanding that the commercial transport aircraft were designed
>with supercritical airfoils to completely avoid the chance of a sonic shock
>forming on the upper wing surface...

As I understand it, one purpose of supercritical wings is to delay shock-
wave formation, pushing it further back along the wing, and to make sure it
appears only at higher speeds.  The advantage being primarily drag reduction.
Supercritical wings (memory tells me) delay the onset to about M 1.0.  

But the shockwaves still exist.  You can see them when the airplane is
flying 90 degrees to the sun; the shockwaves change the refractive property
of air in the vicinity, and can be seen as little span-wise
reflections dancing along the middle to rear of the wing.

Robert Dorsett