Hybrid-Electric Propulsion System for VTOL Drones and Sustainable Air Mobility

The emergence of Advanced Air Mobility (AAM) has prompted significant interest in developing sustainable and highly automated/autonomous flight platforms featuring Vertical Take-Off and Landing (VTOL) capabilities. However, challenges related to limited range and emissions associated with battery-powered electric motors necessitate innovative approaches. This paper proposes a hybrid-electric propulsion management system for VTOL drones based on a mechanically decoupled push–pull hybrid configuration that integrates a puller electric motor and a pusher internal combustion engine. The proposed system coordinates multiple energy sources, including conventional fuel, batteries, solar cells, and hydrogen fuel cells, within a mission-adaptive power allocation strategy designed to optimize energy utilization across different operational objectives. This strategy explicitly links propulsion decisions to mission-level objectives such as emissions reduction, endurance maximization, and flight time minimization. The paper details the hardware functional architecture and software algorithms essential for implementing the power and propulsion management system, ensuring seamless operation and efficient energy utilization. A simulation case study perfomed on a representative VTOL platfrom allows the comparative evaluation of different hybridization levels, demonstrating the practicality of the proposed solution for medium-range and time-sensitive AAM missions.