Hybrid-Electric Propulsion Solutions for UAV Application

Due to the rapid growth of the aviation industry, the concentrations of hazardous pollutants in the atmosphere are rising and the need for more environment-friendly solutions is higher than ever. This study aims to test and show the benefits of hybrid-electric propulsion systems in UAVs in two possible configurations, parallel and series. The hybrid propulsion system combines a 28-cc 2-stroke internal combustion engine with a 200-watt frameless generator. As a primary approach, the engine alone with a 16-inch diameter and 12-inch pitch propeller is characterized by its torque, power and specific fuel consumption throughout the engine’s operating range. In a second approach, the hybrid component is added and a comparison between both results taken is made. Preliminary results show that parallel configuration offers lower specific fuel consumption in comparison with the engine alone. Also, the higher load on the engine used as the primary powerplant seems to promote a more stable operation, with higher throttle control and lower vibrations. In a final remark, considerations regarding the two configurations are made. These considerations aim to establish the best points to operate each architecture and which one is best suited to be implemented on a UAV depending on the mission profile.