Which of the statemets below about a thick airfoil is not true?

Question

A thick airfoil will have a higher (more positive) pressure coefficient than a thin airfoil

A thick airfoil is sometimes needed to store fuel in the wing

With a thick airfoil, the maximum Mach number is lower than for a thin airfoil

Thick airfoils have lower (more negative) pressure coefficients than thin airfoils

Answer 1

The statement that is not true about a thick airfoil is:

Thick airfoils have lower (more negative) pressure coefficients than thin airfoils.

In fact, thick airfoils typically have higher (more positive) pressure coefficients compared to thin airfoils because the flow separation and pressure recovery behaviors differ due to the increased thickness and camber having a more pronounced effect on the pressure distribution around the airfoil.