Improving the UAS-S4 Ehecal airfoil high angles-of-attack performance characteristics using a morphing wing approach

Oliviu Şugar Gabor, Antoine Simon, Andreea Koreanschi, Ruxandra Mihaela Botez (École de Technologie Supérieure, Montreal)

CHALLENGE - In this paper, numerical results obtained for the optimization of the Hydra Technologies S4 unmanned aerial system airfoil are presented. The airfoil modification procedure is based on a morphing wing approach: upper and lower surface changes have been done keeping in mind possible structural constraints.

SOLUTION - The method utilizes a structurally feasible and efficient wing morphing technique to delay boundary layer separation and improve the aerodynamic characteristic of an airfoil at high angles of attack. The boundary layer separation delay, coupled with an increase of the maximum lift coefficient, was achieved using the Artificial Bee Colony algorithm, coupled with the Broyden-Fletcher-Goldfarb-Shanno algorithm. The aerodynamic calculations were performed using a 2D linear panel method, coupled with an incompressible boundary layer 2 model and a transition estimation criterion. A new optimization code, based on a hybrid ABC-BFGS algorithm was used to determine the optimal displacements of the NURBS control points. 

BENEFITS -  Numerical results obtained from modeFRONTIER and MATLAB are presented for the Hydra Technologies S4 UAS airfoil. For very small displacements of the airfoil surface of less than 2.5 mm, lift coefficient increases of up to 18% together with relevant drag reductions have been achieved, successfully delaying separation for the high angles of attack range.