Integration of Hybrid-Electric Propulsion Systems in Small Unmanned Aircraft

Conventional transport aircraft propulsion technology revolves around the use of petroleum-based internal combustion engines, in the form of either aviation turbine fuel or aviation gasoline. Some non-mainstream propulsion technologies are expected to mitigate considerably the environmental impacts in aviation. The integration of hybrid-electric technologies exploits the synergies with distributed propulsion configurations and is therefore one of the most promising approaches to introduce new more sustainable forms of propulsion. This chapter focuses on piston engines and electric motors for light aviation use. It also focuses on a hybrid-electric propulsion system (HEPS) retrofit for remotely piloted aircraft systems (RPAS). Critical parameters for HEPS considered are flight endurance, range, and velocity required to perform such RPAS missions as intelligence, surveillance, and reconnaissance. The chapter explores the use of HEPS specifically implementing a battery and fossil fuel cell combination.