The primary objective of this master's thesis is to examine a new version of a power unit currently utilized in an unmanned aerial vehicle and develop a simulation model of the power unit. The theoretical groundwork needed for developing a model has been presented, describing components used and the function of the different subsystems. The development of a model is done in the simulation environment of Simscape. Measurements were preformed on the physical prototype of the power unit. These measurements were used to verify the simulation. The results of the simulations and the measurements are presented at the end of the thesis, confirming the simulation model's validity.