Design, Development and Integration of a Wing-Morphing, Bimodal Unmanned Vehicle

This paper relates to the design and development of a multi-modal UAV capable of aerial flight and underwater propulsion. A novel hybrid propulsion system has been manufactured and tested. Consisting of folding blades, the propeller has been optimized for propulsion both in air and water. The critical water to air transition phase is achieved by an additional impulsive thruster powered by a C02 cartridge. To decrease the drag in underwater cruise and reduce the potential damage when the vehicle impacts the water, a morphing wing has been developed. This consists of foam-carbon fiber lay-up constructed wings in a variable sweep configuration. The actuation of the sweep is achieved by linear servos mounted on the sleeve shaped spar. An integrated prototype is constructed, using an unconventional, anhedral horizontal stabilizers to allow clearance for the morphing wing. Using a combination of data taken from wind tunnel testing, CFD simulation and analytic methods, models of the vehicles stability are developed with the aim of better understanding the dynamics of the vehicle during transition between the mediums. This will provide information for controller design in future design iterations and identify where modifications to the airframe and transition systems could be made in the optimization of the vehicle.