Some Examples of Airfoil Design for Future Unmanned Air Vehicle Concepts

Abstract

This paper presents design and analysis of three new airfoils for future unmanned air vehicles, operating at relatively low Reynolds numbers. The XFOIL and MSES computer codes were used to design, modify and analyze the airfoils. The first airfoil was designed for the joinedwing SensorCraft concept at Re = 10 6 , with the objective of maximizing section thickness and operation at supercritical Mach number. The second was designed for a new flying wing configuration with upper-surface blowing, operating at Re on the order of 200,000. The new airfoil has a large leading edge radius for ample plenum volume and a region of sharp pressure recovery immediately aft of the blowing slot. The third airfoil was designed for a notional fixed-wing micro air vehicle, operating at Re of 50,000, where the main objective was achieving a closed laminar separation bubble to obtain reasonable lift to drag ratios over a broach range of angle of attack. For the three baseline airfoils, the effects of Re, boundary layer transition parameter, and free vs. fixed transition were investigated. Further work is underway to validate the designs with experiments.