Analysis of Hybrid-Electric Propulsion System Designs for Small Unmanned Aircraft Systems

摘要

Currently fielded electric-powered small unmanned aircraft systems (UAS) lack the endurance desired by warfighters, while their internal combustion engine driven counterparts generate mission compromising acoustic and thermal signatures. Parallel hybrid-electric propulsion systems would meet the military's needs by combining the advantages of hydrocarbon and electric power systems. Three distinct parallel hybrid-electric system designs, each with three unique battery discharging profiles, were analyzed and compared using a constrained static optimization formulation based upon traditional aircraft design equations. Each system combined an internal combustion engine sized for cruise speed with an electric motor sized for endurance speed. The nine variations were compared using a typical intelligence, surveillance and reconnaissance (ISR) mission profile. The analysis determined the most suitable design for the baseline ISR mission and provided recommended missions for the remaining designs.