Non-Linear Analytical Mathematical Modelling of a Hybrid Fixed-Wing Unmanned Aerial Vehicle in Pusher Configuration

To study the flight dynamics of a generic hybrid fixed-wing UAV, the full six-degrees-of-freedom equations of motion of the aircraft are derived. Unlike conventional fixed-wing aircraft or multirotor drones, the flight dynamics of the hybrid aircraft are influenced by both sets of propulsion systems – the main petrol engine and the 4 fixed-rotors. Hence, a derivation of the flight dynamics is presented here as a result of the contribution from both propulsion systems. For this initial attempt, the main petrol engine is fixed at its location and has the sole purpose of providing horizontal thrust only. The position of the petrol engine is located along the X-body axis hence, no moment is created about the center of gravity (CG) by the main horizontal thrust. The 4 fixed rotors, on the other hand, provide vertical thrust along the Z-body axis with the associated roll and yaw. All 4-rotors are positioned on the same X-Y plane on the aircraft body axis. The paper concludes with the aircraft 6 degrees-of-freedom mathematical model of the Vertical Take-off and Landing (VTOL) Fixed-Wing (FW) Unmanned Aerial Vehicle (UAV).