Question

Why does the trailing edge of a supercritical airfoil have a cusp-like shape?

(a) Reduce drag

(b) Counter highly negative camber at the front end

(c) Counter highly positive camber at the front end

(d) Increase fuel carrying capacity in the wing

The question was asked by my school principal while I was bunking the class.

My question comes from The Supercritical Airfoil topic in division Subsonic Compressible Flow over Airfoils : Linear Theory, Linearized Supersonic Flow of Aerodynamics

Answer 1

The correct option is (b) Counter highly negative camber at the front end

The explanation is: Due to the presence of flatter top surface in supercritical airfoil, the 60% of the front end of airfoil is highly cambered resulting in less lift. To counter the reduced lift, positive camber is provided at the bottom aft section of the airfoil by giving it a cusp-like shape. This increases the lift.