At least for now it’s a military bird, but the “Ion Tiger” built by Protonex Technology Corporation, HyperComp Engineering, and Arcturus UAV for the United States Naval Research Laboratory (NRL) is well on its way to demonstrating the practical application of fuel-cell technology in flight. The unmanned aerial vehicle (UAV = drone) recently eclipsed its own record with a sustained flight of 26 hours 1 minute.

The Ion Tiger uses a PEM (Proton Exchange Membrane) system for its fuel cell technology. This system transforms chemical energy liberated during the electrochemical reaction of hydrogen and oxygen into electrical energy. The electrical energy drives production of the ion stream necessary to power the vehicle. The result of this energy production is water. The PEM system is already in use by automotive manufacturers in (mostly experimental) fuel-cell cars. The Navy suppliers have been able to use the same proton exchange membranes as car makers.

The electric fuel cell propulsion system onboard the Ion Tiger has the low noise and signature of a battery-powered UAV, while taking advantage of hydrogen, a high-energy fuel. Fuel cells create an electrical current when they convert hydrogen and oxygen into water and heat. The 550 Watt (0.75 horsepower) fuel cell onboard the Ion Tiger has about four times the efficiency of a comparable internal combustion engine and the system provides seven times the energy in the equivalent weight of batteries. The Ion Tiger weighs approximately 37 pounds and carries a 4- to 5-pound payload.

NRL has now demonstrated that PEM fuel cell technology can meet or surpass the performance of traditional power systems, providing reliable, quiet operation and extremely high efficiency. Next steps will focus on increasing the power of the fuel cell to 1.5 kW, or 2 HP, to enable tactical flights and extending flight times to 3 days while powering tactical payloads.

[Source: US Navy]