The Hybrid Tiger Long Endurance Solar/Fuel Cell/Soaring Unmanned Air Vehicle

R. Stroman
US Naval Research Laboratory, District of Columbia, United States

Keywords: unmanned, fuel cell, solar, endurance, aircraft

Hybrid Tiger is a Group II (< 55 lb.) Unmanned Aerial Vehicle (UAV) that is expected to achieve flight endurance greater than four days at a range of greater than 2,000 nmi. The Naval Research Laboratory (NRL) is developing the Hybrid Tiger under the FY15 Operational Energy Capability Investment Fund (OECIF) data call topic of Unmanned Systems for the Pacific. Hybrid Tiger has a unique hybrid power system that adapts to the energy available within the environment and also incorporates route optimization software to make the anticipated range and endurance possible. The hybrid power system combines a Proton Exchange Membrane Fuel Cell (PEMFC), Photovoltaic (PV) solar arrays, and autosoaring. The PEMFC and hydrogen fuel were chosen because they provide 10 times greater specific energy than Li-Ion batteries (2300 Wh/kg vs 200 Wh/kg). Fuel consumption is offset during daylight hours by five PV solar arrays. An on-board computer manages the Hybrid Tiger power system and attempts to follow an optimal route to the destination - either minimum travel time or maximum stored energy (fuel) upon arrival. Identification of the optimal route is decomposed into semi-independent global and local path planning tasks.