May 15, 2018

The US Naval Research Laboratory (NRL) will be adding solar technology to its Hybrid Tiger unmanned aerial vehicle (UAV) as it seeks to achieve a flight duration of over three days for the system.

NRL has awarded Alta Devices a contract to deliver its light-weight solar technology for the UAV.

Alta Devices noted that technologies developed for the project would be applicable to other unmanned vehicles.

The Hybrid Tiger program integrates multiple technologies into a single UAV designed for long range endurance. It will use high-efficiency flexible solar cells, a hydrogen fuel cell, and energy-aware guidance algorithms. The program is sponsored by the Office of the Deputy Assistant Secretary of Defense for Operational Energy and the U. S. Marine Corps Expeditionary Energy Office.

The Hybrid Tiger UAV planned demonstration includes flights over multiple days, during the winter solstice and as far North as 50 degrees latitude to highlight how extreme endurance UAV flight can be achieved using hybridization of solar photovoltaics, a hydrogen fuel cell, and autonomous soaring algorithms, regardless of latitude or time of year.

“Widespread use of small UAVs in both the military and industry has been limited to-date by endurance. The Hybrid Tiger will demonstrate that very long endurance flights, with sophisticated telemetry and capabilities, can be achieved with the inclusion of solar arrays,” said Jian Ding, Alta Devices CEO. “This project will open the door for many new solar powered UAV applications, and we look forward to achieving next generation breakthroughs via this cooperative effort.”

Ion Tiger’s electric fuel cell propulsion system has the low noise and low signature of a battery-powered UAV, while taking advantage of hydrogen, a high-energy fuel. The 550-W (0.75-horsepower) fuel cell has about four times the efficiency of a comparable internal combustion engine.

The Ion Tiger flew for 26 hours in November 2009 while carrying a 5-pound payload using hydrogen compressed to 5000-psi in a carbon/aluminum pressure vessel. In May 2013, the same researchers at the U.S. Naval Research Laboratory flew their fuel cell powered Ion Tiger UAV for 48-hours and 1 minute on April 16-18 by using liquid hydrogen fuel in a new, NRL-developed, cryogenic fuel storage tank and delivery system.