The Sportsman STOL wing cuff is a state of the art modification originally designed by Lockheed Skunkworks to increase light plane utility and safety by increasing the wings efficiency and resistance to stalls and spins. The Sportsman STOL is not just a lip on the bottom, but is a re-engineered airfoil. The aim of the Sportsman STOL modification is to improve aerodynamics and enhance aircraft performance and safety.