A propulsion system for a vertical take-off and landing ducted fan aerial vehicle is provided, the propulsion system comprising an internal combustion engine, an electric motor that comprises a motor generator, a motor drive and a battery. The motor drive and battery are integrated into the aerial vehicle and provide power to the ducted fan aerial vehicle. The electric motor may comprise a ring motor generator. In operation, this dual propulsion system serves as a weight-efficient option to allow for two sources of power on a ducted fan unmanned aerial vehicle.