Researchers at the U.S. Naval Research Laboratory (NRL) have set a new continuous flight record with an electric drone powered by a fuel cell running from liquid hydrogen in cryogenic storage.
NRL researcher Karen Swider-Lyons said liquid hydrogen is three times denser than 5000-psi compressed hydrogen, allowing more hydrogen to be carried onboard to increase flight endurance. “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,” she said.
Stealthy electric powered drones are more desirable than noisy conventional hydrocarbon-fueled craft, but endurance issues have dogged electric UAVs until now.
Source: U.S. Naval Research Laboratory