The document calculates percentage errors between theoretical and experimental values for lift (CL), drag (CD), and lift-to-drag ratio (CL/CD) at various angles of attack (α) for an NACA 23018 airfoil using data from wind tunnel tests and the XFLR5 software. Percentage errors are provided for comparisons of CL vs α, CD vs α, CL vs CD, and CL/CD vs α between the NACA 23018 airfoil and wind tunnel data and between the airfoil and XFLR5 data.