altough the drag/eas curve is one of the most remarquable one in aerodynamic. I believe that in our application it's more intersting to base our speculation on the PN/Eas curve.
99 procent of us fly with internal combustion engines turning a conventional propeler after all......

here is a synthesis of the comparaison of the two curves I made 15 years ago. If you want more explanation and theory about some interesting points on the curve, feel free to ask.

compressibility drag has been omited in those curves