Flying emplacement of an underwater glider

An unmanned vehicle is envisioned for multi-modal operation, first as an aircraft, then as an underwater glider. The benefits of a “Flying Sea Glider” are for high-speed flying ingress above the water and then maneuvering in an area of interest as a low-speed, long-endurance underwater glider. This development builds on previous NRL research in multi-modal designs and bio-inspired propulsion systems, with a new emphasis on reducing power required in both air and underwater. Considerations for flying and underwater gliding vehicles are vastly different, despite the aero/hydrodynamic overlap. This paper explores design trades and analysis for a vehicle designed to operate in these two media. To explore the concept, NRL Test Sub 3 was developed and tested. The resulting vehicle demonstrated flight, splashdown, and gliding performance in one vehicle, validating the multimodal flying and gliding design concept. Taken together with an analysis, the demonstration shows the viability of an unmanned “Flying Sea Glider” vehicle.