In the Doctoral Thesis, an unmanned aircraft system for special purposes has been designed for military or law enforcement needs. The novelty of this system is the increased flight duration of the unmanned aircraft and a new type of landing system. The Thesis analyses the research that has been carried out so far in the field of unmanned aircraft systems, selects the most appropriate conceptual unmanned aerial vehicle design model, develops a computer simulation of the developed aircraft model, as well as performs conceptual and experimental dimensional analysis of unmanned aircraft systems and carries out the system design modelling and technical parameter testing in the MATLAB computer program in order to verify the systems performance and compliance of the parameters with the requirements.