2018 AIAA Aerospace Sciences Meeting

An integrated hybrid propulsion system of a multi-modal UAV capable of sustained aerial flight, locomotion in water and deployment from a torpedo tube is under development. This paper covers the design and optimisation of integrated hybrid and separate propellers, as well as structural analysis and propeller placement. Hybrid propellers are designed to allow the propulsion system to operate efficiently in both domains with a single propeller while the separate propeller system is intended for maximum efficiency by utilising a different propeller for each domain. Motors are designed for both types of propellers, with challenges and alternative solutions proposed. The separate propeller design is a novel design which proposes the integration of two shaftless motors into a single motor for optimal efficiency. The selection, sizing and design of an aerial/aquatic transition mechanism is performed, along with a valve designed to regulate the mechanism for efficient and sustained thrust. Experiments are carried out for the aerial propeller and gas transition experiments to validate the theoretical results. Future work is also proposed with areas for improvement and development.