Validation of Aerodynamic Coefficients for Flight Control System of A Medium Altitude Long Endurance Unmanned Aerial vehicle

Stability and manoeuvrability have been the major trade-off in the design of aircraft both for civil or military usage. Hence, the need to design a suitable system for the control of the flight control surfaces (Elevator, Rudder and Aileron) on the aircraft. The flight control system (FCS) design helps resolve both the flying and handling qualities of the Unmanned Aerial Vehicles (UAV); it makes use of Stability Augmentation System (SAS) as a feedback mechanism tool for the FCS. Therefore, this paper discusses the validation of FCS for a Medium Altitude Long Endurance (MALE) UAV, whose service ceiling is 15,000 ft., having an endurance of up to 20 hours. A six degrees of freedom (DOF) aircraft model was used to test both the longitudinal and lateral/directional stabilities of the aircraft. Conceptual design parameters were used to generate both the dimensionless and derivatives of the MALE UAV using the AVL software. The results generated from AVL were validated using the digital DATCOM applications and both applications gave satisfactory results though with slight variations in the values of the coefficients obtained from both applications.