Transonic Airfoil Development for an Unmanned Air System

Abstract

The process of developing a new energy efficient 16% thick airfoil for an unmanned air system operating at transonic speeds is presented. The airfoil specifications included a range of Reynolds number per foot from 1.7 million to 2.5 million and Mach number from 0.4 to 0.8. Shape optimization in geometry and inverse design modules of the MSES program were initially used for a preliminary design of the 16% thick airfoil. The MSES/LINDOP program was then used to obtain the final airfoil shape, optimizing the performance of the initial airfoil with an objective of minimizing drag coefficient for seven design points with conflicting requirements in Reynolds and Mach number. The optimization produces an upward shift of drag bucket in the direction of higher lift coefficient. This shift is also seen on the location of transition producing an increase in the extent of laminar flow. © 2025 Elsevier B.V., All rights reserved.