With the developments in technology, the usage areas of Unmanned Air Vehicle (UAV) systems become widespread and diversify. Nowadays, UAVs are used for many different purposes such as remote sensing, photogrammetry, traffic control and monitoring of large facilities. In this work, a quadcopter was built as UAV. The eCalc program was used to extract the performance characteristics of this quadcopter. eCalc's design process and simulation processes are interactive. With the eCalc, the real elements can be created which are very close to the reality. The results obtained with eCalc were compared with the results obtained from MATLAB applications, and the hardware and software architectures required for an UAV general system and subsystems were designed and the quadcopter to be used in practice was realized. Mission Planner was used as a ground control station.