Aerodynamic Coefficients Computation for Fixed Wing Aircrafts Using DATCOM Software with Emphasize on Rudderless Flying-Wing UAVs

The fixed-wing unmanned aerial vehicles (UAVs) have gained significant attention across diverse civilian and military applications in recent years, where precision control, advanced manoeuvrability, and elevated stealth capabilities are paramount. In order to design a robust control system to enable different tracking and path-following purposes, it is desired to establish a precise aerodynamic model. The research introduces a straightforward approach for accurately computing aerodynamic coefficients, essential for deriving aerodynamic forces and moments, particularly focusing on the rudderless flying-wing UAV models. Utilizing Digital DATCOM software, the study outlines a procedure for calculating the requisite aerodynamic coefficients of fixed-wing aircrafts. The data input card is prepared based on the design and physical attributes of the rudderless flying-wing Freya UAV model and its associated airfoil structure. Through the utilization of the input card in DATCOM software, computations are performed to determine static longitudinal/lateral stability, dynamic stability, and control coefficients, along with their derivatives. Additionally, a 3D model is constructed. The ensuing output file is then imported into the MATLAB environment for comprehensive analysis and integration into dynamic modelling for the design of control systems. The open-loop and closed-loop system performance analysis based on the obtained aerodynamic coefficients, shows acceptable values in terms of control surfaces and flight dynamics variables in the category of small-sized rudderless flying-wing UAVs which proves the reliability of the obtained results.