Fuel Cell FAQs

Mission requirements change – and not just by the month or year, but by the day or hour. The more flexible the uncrewed aircraft executing the mission, the greater the ability to pivot and adapt to meet these changing requirements. An effective UAS solution offers options that address long range and long endurance operations while remaining silent, light, and mobile, which is essential to overall preparedness and mission success.

Answering the Need for Options

While the logistics footprint of airborne intelligence, surveillance, and reconnaissance (ISR) grows smaller, the requirements surrounding mission needs continue to expand. Small uncrewed aircraft systems (sUAS) and Group 2 UAVs are now expected to successfully complete operations that used to be in the purview of larger aircraft.

This means that the aircraft must not only be smaller and lighter but must also have the system flexibility to meet a wide variety of mission needs. Whether this means operations in sub-artic temperatures, nighttime or low light flights, the addition of multiple payloads, long-range targets, or any of a long list of challenges, an effective sUAS platform needs to offer options that are easy from a logistics and operational standpoint.

“A more robust common operating picture is vital to mission success,” says Josh Stinson, Edge Autonomy Chief Growth Officer and Army Special Forces Veteran. “To achieve greater awareness of the operational environment, today’s warfighter needs to see farther and understand more. The mission flexibility of an uncrewed system and its ability to provide greater dwell time in that environment directly impacts the effectiveness of the warfighter.”

And what feature has a major influence on the overall endurance of an sUAS? Its power source.

In recent years, the requirement for silent propulsion systems has emerged as a must-have feature of an sUAS. The majority of ISR operations require the sUAS to remain undetected while performing its mission. Unfortunately, silent operations are effectively impossible with a traditional internal-combustion engine. Hence, most sUAS have moved towards all-electric propulsion systems and utilize high-energy batteries as their energy source. But an sUAS that relies only on batteries (including even the most advanced battery technologies) has significant limitations compared to an sUAS with a traditional propulsion solution, most notably a major reduction in range, endurance, and payload capacity.

What if a new power system could plug directly into the battery slot on an sUAS and provide four times greater endurance, range, and payload capacity while still remaining silent? And what if this product could be hot swapped with batteries from one flight to another depending on the needs of the mission? Edge Autonomy has developed this technology and is currently flying with it across six continents, performing flight operations in the most austere and harsh conditions.

TRL 9 flight proven through successful operations, our micro-tubular solid-oxide fuel cell (MT-SOFC) runs on propane, unlike common fuel cells that run on hydrogen. And with our advanced onboard filtration system, the MT-SOFC can consume the dirtiest propane you can find. This means that you can grab a propane canister from a military kitchen, a local BBQ stand, or a rundown gas station in the middle of nowhere. Best of all, propane is used in every city and village on earth, so a fresh (or dirty) can of propane is always available without special logistics.  

Moving Beyond Just the Battery

With nearly four decades of aeronautical innovation, Edge Autonomy has seen the battlefield evolve, and with that evolution we have pioneered breakthroughs in technology that move in lock step with our customers’ missions. While continuously pushing the limits of long endurance and long-range reconnaissance, our uncrewed aircraft systems have remained adaptable for each unique intelligence, surveillance, and reconnaissance mission we fly.

As the original equipment manufacturer (OEM) of the VXE30 Stalker UAS and its advanced Havoc configuration, Edge Autonomy has equipped these aircraft with state-of-the-art batteries that can achieve a flight time of six hours on electric power alone. When the mission calls for even longer range or greater endurance, batteries can be swapped with our MT-SOFC that is not only easily accessible and field swappable, but capable of extending mission parameters by up to four times farther in terms of distance, flight time, and payload capacity. And because the system remains all electric even under fuel cell power, the VXE30 Stalker and Havoc configuration maintain silent operations throughout the entire flight.

We have spent the last 25 years honing our MT-SOFC technology by testing it across a variety of operational areas around the world in harsh weather conditions. Powered by propane, this technology increases the flight time of our battery-powered UAS and has already proven effective in long-range operations with hundreds of thousands of hours flown across six continents.

The result? The VXE30 provides maximum mission flexibility by allowing the operator to choose between battery and fuel cell on every flight. If you have a few batteries charged up and only need to fly 4-6 hours, then plug a battery into the aircraft and takeoff. However, if your mission demands significantly greater range and endurance, then plug the fuel cell into the aircraft and takeoff. A fuel cell is not a replacement for the batteries on a VXE30, it’s just an additional tool available to the operator to dramatically boost endurance and range on the missions that require it.   

Achieving Mission Success with Any Propane, Anywhere

When executing a successful ISR mission, every second counts and every gram of payload weight matters.

“Imagine a drone operator flying a long-range mission in a remote environment,” says Dr. Tom Westrich, VP of Technology at Edge Autonomy. “The combination of a battery and fuel cell – like we see in the VXE30 Stalker – extends the flight, but if refueling means the need to carry specialized fuel then the mission is ultimately made less efficient.”  

By equipping aircraft with a small, lightweight, and proven fuel filtration system, Edge Autonomy ensures that soldiers in the field have the autonomy to refuel the Stalker with any available propane, whether from a petrol station, a convenience store, or a kitchen in a nearby village. With no need to source specialized propane, mission operations can continue without the inconveniences of added time and expense.

How does this innovative fuel cell filtration system work?

Sulfur and other odorants are added to most propane and natural gas sources, but over time these inhibit the electrochemical reaction needed to generate power from a fuel source.

The unique filtration system within Edge Autonomy’s fuel cell captures these additives, resulting in a clean, immediately usable fuel for optimal operational efficiency.

Fuel cells that rely on other energy sources—such as hydrogen—must depend on the creation of metal hydrides, a complex chemical process that cannot be completed easily in the field, which gives hydrogen-based fuel a much larger logistical footprint.

“But a soldier can locate propane in almost any environment,” says Westrich. “And because of our unique filtration system, it doesn’t matter how dirty that propane is—the UAV operator can simply fill a tank from ANY source and use that to directly power the VXE30 Stalker. They’ll be flying again in minutes.”

How long does this refueling process take?

“To hot swap a single tank on a fuel cell for the VXE30 Stalker, you need about 20 seconds—at most 60 seconds if you’re taking your time,” Westrich explains.

Switching out the two fuel tanks and filters on the VXE30 advanced Havoc configuration doesn’t take much longer, as both are located externally on the aircraft’s wings, making them easily accessible.

Innovations That Take ISR Missions Farther

The long-term mission benefits and potential savings of a UAV with a proven dual power source are significant.

“Longer flight times and more range increase overall mission efficiency, as well as the likelihood of success,” says Stinson. “Buying the operator the time and flexibility needed to accurately assess each situation provides the opportunity to respond to the most immediate needs of the battlespace.”

And increased flight time and range aren’t the only advantages when it comes to in-field operations.

“Every piece of equipment and pound of weight makes a difference to the warfighter,” Stinson explains. “When you don’t have to account for additional batteries or specialized fuel with your supplies you have room for other essentials like food, water, and ammunition.”

The VXE30 Stalker’s dual power source gives it greater range and endurance compared to similar sUAS on the market, and the flexibility the aircraft offers in fuel sourcing means greater efficiency as well.

“We consider our customers’ missions to be our missions as well, and we are constantly innovating toward greater success and efficiency for them,” says Stinson. “I’ve been there myself, as have many of our researchers and engineers, and we appreciate the technology that goes into battlefield operations.”

Learn more about our VXE30 Stalker, the Havoc configuration, and the technology behind our innovations.

FLY FARTHER. FLY LONGER. CARRY MORE.