A long endurance high efficiency Unmanned Aerial Vehicle (UAV) is being developed by a group of researchers and students in the Mechanical Engineering Technology program at Algonquin College, Ottawa, ON, Canada. The design is based on a tailless, staggered tandem wing configuration, with a carbon fiber frame and electric propulsion. The developed aircraft has a maximum weight of 12.5 kg, well within the 25 kg limit outlined by Transport Canada for permission-free operation. The UAV was designed to fly missions exceeding 24 hours, performing surveillance and oil pipeline monitoring and inspection, either autonomously or under radio control from a ground station, with medium to high payload capacity.This paper describes the process of designing, manufacturing and testing the developed configuration. The operational requirements are delineated as conceptualized by the development team. A description of the prototype development, including aerodynamics, structural and stability performance, and stability derivatives is included, based on data generated through analytical analysis, simulations in the aerodynamics and stability design software, XFLR5, and testing. The configuration was developed and modeled in the software package SolidWorks, leading to the manufacturing plans for the prototype. As this UAV performs radio controlled and autonomous flights, it makes use of the APM Arduplane, which is an open source hardware and software autopilot package. In order to achieve PID tuning, Hardware in the Loop (HIL) simulations were performed between the autopilot board and two computers simultaneously running the Mission Planner software and the flight simulator X-Plane 10 software. A description of this tuning process is provided. The paper concludes with the results of performed flight tests, documenting performance achievements, and an outline of recommendations for further development.