Aerodynamic Centers of Symmetric Diamond Airfoils in Inviscid Supersonic Flow

The axial location of the aerodynamic center of a supersonic airfoil varies with the angle of attack, airfoil thickness, and Mach number. It does not consistently lie at the traditional half-chord (c/2) position. Additionally, the normal location of the aerodynamic center is also a function of operating conditions. This paper applies a more accurate method for determining the aerodynamic center of supersonic airfoils, which includes aerodynamic and trigonometric nonlinearities. Specifically, it presents a procedure for locating the aerodynamic center of thin airfoils and symmetric diamond-shaped airfoils, and can also be applied more generally using aerodynamic data for any airfoil in supersonic flow. The method requires first and second derivatives of the aerodynamic normal, axial, and moment coefficients with respect to angle of attack. This approach enables a more precise estimation of the aerodynamic center of airfoils in supersonic flow, supporting improved aircraft design, stability predictions, and aero-structural modeling. Results are compared to those from traditional approximations, which demonstrate that traditional approximations can introduce errors on the order of 10% for airfoils of typical thickness on supersonic aircraft.