Development of Small Internal Combustion Engine Thrust Stand/Dynamometer

Current US military small unmanned aircraft systems (UAS) rely on engines and propellers sourced from the hobby radio-controlled (RC) aircraft industry. They require special fuel and in general have poor fuel efficiency. There is an urgent need to develop research capabilities to characterize and improve the efficiency of these small engines and develop the ability to operate on the available in-theater heavy fuels (JP8/kerosene). This paper describes the development of a small internal combustion (IC) propeller engine test stand capable of measuring both thrust and torque simultaneously under both static and dynamic conditions. The calculated uncertainty is found to vary from ± 10.4% to ± 1.7% for the range of interest. Torque, thrust, power, brake specific fuel consumption, (BSFC) and propeller efficiency data for a UAS engine are presented.