LONGITUDINAL FLYING QUALITY ANALYSIS FOR A SMALL FIXED-WING UAV MODEL

Abstract

This article presents a detailed analysis of the longitudinal flying qualities of a small fixed-wing unmanned aerial vehicle (UAV). The UAV model is developed using MATLAB/Simulink, supported by the Aerospace Blockset for six-degree-of-freedom dynamic modeling. Aerodynamic coefficients are obtained from Digital DATCOM based on the UAV’s geometry and operating conditions. A trimmed flight state is determined, and the nonlinear model is linearized to extract longitudinal dynamics. The short-period and phugoid modes are analyzed according to MIL-STD-1797A criteria. Results indicate that the UAV meets Level 1 requirements for both modes, with the short-period damping ratio near the lower limit and the natural frequency well above the minimum threshold. These findings clarify the UAV’s inherent dynamic behavior and provide a foundation for future control system development and flight performance optimization.