The GAW-1 airfoil is a modified Supercritical airfoil and started out as
the 17% supercritical airfoil that we tested on the Navy trainer T2C and
was the first supercritical airfoil to be demonstrated in flight, it has
a flat pressure distribution on the upper surface that allowed laminar
flow back about 55 % chord at subsonic speeds and was used on the
varieasy wing. A varieasy was investigated in the NASA full scale wind
tunnel to confirm this. This airfoil was used on a supercritical prop
designed by Jim Raisback in the mid - seventies, He said it worked well
but I never seen any data on it, it would be something to consider for
the outboard 20 % of the prop that may reach supersonic speeds on the
convair if you get over 3000 RPM. Supercritical does not mean the same
thing as very critical as some people have indicated. It was named
Supercritical because it has supersonic flow on the upper surface without
shock induced separation, this can give a 15 to 20 % increase in speed
without wave- drag.
Sincerely
James C. Ferris
