Special operators in remote locations will soon have the ability to refuel one of their hand-launched unmanned aerial systems (UAS) simply by visiting a local market.
Lockheed Martin’s Stalker eXtreme Endurance (XE) UAS—the recently released upgrade to the Stalker which has been in use since 2006—was developed to use a propane fuel cell with a small, conventional lithium polymer battery.
The long-endurance fuel cell upgrades the flight time for the bird from about two hours to about eight, says the company’s Thomas Koonce, program manager for special programs. Koonce told Aviation Week at the Unmanned Vehicle Systems International show on Thursday that the company completed testing of the upgraded, 13-lb UAS in May, and the day of the final demonstration received orders from several “U.S. customers”—though he declined to say who. (Given the system’s history with the Special Forces, one can guess….)
During demonstrations, the UAS was able to perform repeated long-endurance missions with only 30 minute breaks in between, flying in high winds and at altitudes that reached 16,000ft, Koonce said, adding that the vehicle proved that it could keep up this hectic pace even when repeatedly landing in rocky, and otherwise inhospitable terrain.
Even with the increased endurance, Koonce said, Lockheed engineers were able to slightly decrease the weight of the UAS on the new XE model. The fuel cell technology was developed through a Defense Advanced Research Projects Agency effort that was led by Lockheed Martin and Adaptive Materials Incorporated. The use of propane fuel cells appears to be catching on -- this summer, the Army sent a propane-based fuel cell to Afghanistan for field testing in hopes that soldiers will be able to rely on local markets for their fuel needs.
Pic: Lockheed Martin