This study investigates energy and entropy analyses of an experimental turbojet engine build in Anadolu University Faculty of Aeronautics and Astronautics Test-Cell Laboratory.  Law of motions and Brayton thermodynamic cycle model are used for this purpose. The processes (that is, compression, combustion, and expansion) are simulated in P-v, T-s and h-s diagrams. Furthermore, the second law of thermodynamics is applied to the cycle model to perform the entropy analysis. A distribution of the wasted and thrust power, the overall (energy-based the first law efficiency), and the specific fuel consumption and specific thrust of the engine were calculated during the analyses as well. The results of the study also show the entropy changing value in engine components due to irreversibilities and inefficiencies. As a conclusion, it is expected that this study is useful to study future design and research work similar aircraft turbojets, auxiliary power units and target drone power systems.