Improvement of Aerodynamic Characteristics of an Airfoil by Static Extended Trailing Edge

Abstract

The objective of this work is to study the SETE as an alternative flow control technique for lift enhancement at a small drag penalty in cruise flight. The geometrical quantities, chord distribution and other properties are given in convenient analytical expressions.The experiment was about to enhance the lift of NACA0012 airfoil with static extended trailing edge (SETE). A thin sheet was introduced to the wing trailing edge as a mechanical device without changing the basic configuration of the wing. Calculations were done to compare the coefficient of lift using static extended trailing edge (SETE) with those of using flap. The effects of SETE on the wing aerodynamics are mainly due to modifications of the airfoil camber and the flow structure at the trailing edge. The lift enhancement by the SETE is, expectedly, due to the camber effect. It is speculated that the drag penalty of the SETE is small because it is usually embedded in the wake of the main airfoil. Experimental results are presented, including the lift and drag coefficient of the baseline NACA0012 airfoil model and of model with the SETE and Gurney flaps. The lift enhancement is achieved by the SETE, whereas the drag polar and lift-to-drag ration remains largely unchanged. The zero-lift drag and Oswald’s efficiency are not significantly affected by the SETE. The benefit analysis for the SETE in cruise flight is given in comparison with Gurney flap.