Aerodynamics and Structure of a Large UAV

Abstract: This thesis investigates what design of a large UAV performing VTOL using only electrical motors is the most viable in terms of extending its range. Because it uses batteries for power, its powered time is limited, posing the need for a way of extending its flight time. By using a tiltwing design, its vertical flight time is cut at the same time as it will be able to perform as a glider, increasing its range drastically. To achieve the best lift-to-drag ratio, the high-lift F3B RG15-airfoil was chosen, giving the UAV a lift-to-drag ratio of 36,48, and a maximum range per descend glide of approximately 25,5 kilometers. The fuselage will be a simple, aerodynamic body just big enough to hold the batteries and the load while giving the wing the ability to tilt without interfering with the rotors. The material used in this thesis comes from a company which produces high-strength carbon fiber tubes and rods as well as a 3k twill weave carbon fiber prepreg for the skin, making the structure as light and strong as possible. The result is an aircraft with a structural weight of 56,6 kilograms that is strong enough to lift with a combined weight of 495 kilograms and at the same time perform a safe glide flight.