Lift Coefficient Prediction Versus Angle of Attack: A Polynomial Representation Based on A VLM-DATCOM Hybrid Model
Year: 2026
Type: article
Abstract: The typical function of lift coefficient versus angle of attack (the lift curve) is represented by a linear function with two coefficients and beyond its linear range by a third order polynomial with four coefficients. These coefficients are determined from five aerodynamic parameters: lift curve slope, maximum lift coefficient, stall angle (at which the maximum lift coefficient occurs), zero-lift angle of attack, and the angle at which flow separation effects begin to develop. These five parameters can be obtained from simple aerodynamic equations or – proposed here – better by a VLM-DATCOM hybrid model. The polynomial is derived from first principles. VSPAERO is employed as the Vortex Lattice Method (VLM) solver, and the DATCOM equations for maximum wing lift are reviewed. Exemplary results are compared with wind tunnel measurements, CFD analysis, results from Athena Vortex Lattice (AVL) and XFLR5, as well as with simple aerodynamic equations. Both the linear and polynomial representations of the lift curve are independent of the method used to obtain the aerodynamic parameters. The VLM-DATCOM hybrid model (combined with XFOIL to find airfoil parameters) is a suitable approach for estimating aerodynamic parameters. In an example case, the model yielded an error of 5% for the lift curve slope and 9% for the maximum lift coefficient when compared to wind tunnel measurements. However, the VLM–DATCOM hybrid model may have limitations for wings with significant twist.
Authors: M. Sahraoui, M. Mekadem, A. Boutemedjet, D. Scholz
Institution: HAW Hamburg
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7168047583