The UAV, flown by researchers at the U.S. Naval Research Laboratory flew their fuel cell powered UAV for 48 hours and 1 minute using liquid hydrogen fuel in a new, NRL-developed, cryogenic fuel storage tank and delivery system.
The previous record for the vehicle, using gaseous hydrogen stored at 5,000 pounds per square inch, was 26 hours, 2 minutes.
"Liquid hydrogen coupled with fuel-cell technology has the potential to expand the utility of small unmanned systems by greatly increasing endurance while still affording all the benefits of electric propulsion," said Karen Swider-Lyons, NRL principal investigator.
The Naval Research Laboratory said liquid hydrogen is three times denser than compressed hydrogen. The cryogenic liquid is stored in a lightweight tank, allowing more hydrogen to be carried onboard to increase flight endurance.
The flight using the new fuel system is more reliable than conventional hydrocarbon-fuel power systems and provides greater endurance than battery power, NRL said.