A review of internal combustion engines applied to unmanned aerial vehicles

Internal combustion engines constitute one of the two fundamental propulsion categories used in unmanned aerial vehicles (UAVs). This article analyzes the occurrence and application of individual types of internal combustion engines across unmanned platforms, with particular emphasis on their influence on aircraft performance and mission profiles. The advantages and limitations of specific propulsion system configurations are identified in the context of unmanned aviation, including factors such as energy efficiency, mass, structural complexity, endurance, and acoustic and thermal signatures. In addition, representative UAVs employing different types of internal combustion engines are presented, illustrating the practical implications of propulsion system selection in real-world operational applications.