The Naval Research Laboratory's Ion Tiger - a hydrogen-powered fuel cell unmanned air vehicle (UAV) - flew for 26 hours and 1 minute carrying a 5-pound payload, setting an unofficial flight endurance record for a fuel-cell powered flight. The test flight took place November 16-17.

Nearly undetectable from the ground, UAVs are widely used by the military to scan terrain for possible threats and intelligence. The Ion Tiger weighs approximately 37 pounds and carries a 4- to 5-pound payload.

The electric fuel cell propulsion system onboard the Ion Tiger has the low noise of a battery-powered UAV, but the system provides seven times the energy in the equivalent weight of batteries. The 550 Watt (0.75 horsepower) fuel cell has about four times the efficiency of a comparable internal combustion engine.

The Ion Tiger fuel cell system development team is led by NRL and includes Protonex Technology Corporation, HyperComp Engineering, and Arcturus UAV. The program is sponsored by the Office of Naval Research.

NRL has now demonstrated that PEM fuel cell technology can meet or surpass the performance of traditional power systems, providing reliable, quiet operation and extremely high efficiency. Next steps will focus on increasing the power of the fuel cell to 1.5 kW (or 2 HP) to enable tactical flights, and extending flight times to 3 days while powering tactical payloads.

(Naval Research Laboratory)