NRL Shatters Endurance Record for Small Electric UAV

This flight shatters their previous record of 26 hours and 2 minutes set in 2009 using the same vehicle, but with gaseous hydrogen stored at 5,000 pounds per square inch (psi).

WASHINGTON--Researchers at the U.S. Naval Research Laboratory flew their fuel cell powered Ion Tiger unmanned aerial vehicle (UAV) for 48 hours and 1 minute, April 16 to 18, by using liquid hydrogen (LH2) fuel in a new, NRL-developed, cryogenic fuel storage tank and delivery system. This flight shatters their previous record of 26 hours and 2 minutes set in 2009 using the same vehicle, but with gaseous hydrogen stored at 5,000 pounds per square inch (psi).


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. Success in flight requires developing a high quality, lightweight insulated flight Dewar for the cryogenic fuel, plus matching the boil off of the cryogenic hydrogen to the vehicle fuel consumption.

"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 Dr. Karen Swider-Lyons, NRL principal investigator.

Although long endurance is possible with conventional, hydrocarbon-fueled systems, these are usually loud, inefficient, and unreliable in this aircraft class. Similarly, small, electric, battery-powered systems are limited to endurances of only several hours.

To address the logistics of in-theater supply of liquid or gaseous hydrogen, NRL proposes in-situ manufacture of LH2 for use as fuel. An electrolyzer-based system would require only water for feedstock and electricity, possibly from solar or wind, to electrolyze, compress and refrigerate the fuel.

The NRL LH2 flight capability is being developed by NRL's Tactical Electronic Warfare and Chemistry Divisions, and is sponsored by the Office of Naval Research.

The U.S. Naval Research Laboratory is the Navy's full-spectrum corporate laboratory, conducting a broadly based multidisciplinary program of scientific research and advanced technological development. The Laboratory, with a total complement of nearly 2,500 personnel, is located in southwest Washington, D.C., with other major sites at the Stennis Space Center, Miss., and Monterey, Calif. NRL has served the Navy and the nation for over 85 years and continues to meet the complex technological challenges of today's world. For more information, visit the NRL homepage or join the conversation on Twitter, Facebook, and YouTube.

Featured Product

Stäubli – Robotic tool changers

Stäubli - Robotic tool changers

Stäubli offers a complete range of robotic tool changing systems for payloads of 20 kg to 1,530 kg and torsion moments from 30 to 12,500 Nm, designed for use in virtually every industry. The tool changers adapt to customer-specific applications with different modules for media, data, power, etc. The new MPS 130 robotic tool changer is powerful, very robust, and designed for a huge range of applications. It features multiple couplings for air/vacuum connections, and can be equipped with connectors for data and electrical transmission. Very compact dimensions, with a coupled height of only 67 mm, make the MPS 130 the first choice for applications requiring a high number of mating cycles.