Fabrication and Qualification Studies of Aluminum Fuel Tank for Experimental UAV

Abstract

Unmanned Aerial Vehicles (UAVs) are reusable, controllable air vehicle having sustained flight throughout its mission and are widely being utilized for various military and civil applications. Aluminum and its alloys is one of the extensively used non-ferrous metals in aerospace engineering applications due to its excellent properties like higher strength to weight ratio, goodmachinability and excellent formability. However, welding of aluminum and its alloys has always been a challenge due to drastic reduction in strength near heat effected zone. This paper mainly discusses aspects considered in design of pressurized aluminum alloy fuel tank for subsonic Experimental Unmanned Aerial Vehicle (XUAV). The fuel tank is the central module of the fuselage of the aircraft, and is shaped to minimize the stress and minimize sloshing. In the present paper, various weld joints utilized in propellant tank are presented. Also, the welding sequence evolved for fuel tank fabrication, assembly and in-process non-destructive inspections are discussed. Studies were carried out on prototype tank for its qualification namely fuel capacity check, leak test, pressure test, flow rate test etc. The satisfactory result of theoretical and experimental study implies that the fuel tank meets all the design requirements and altitude independence.