The SuperStack Flex is a modular, high-performance power and propulsion unit designed to deliver exceptional power-to-weight ratios across a range of aerospace applications. It can be configured to meet specific mission needs, offering scalability and flexibility for both propulsion and auxiliary power requirements.

Developed with an aerospace-optimised, lightweight balance-of-plant, the system has been engineered to extend the range and endurance of Unmanned Air Vehicles (UAVs), while maintaining potential adaptability for maritime and ground systems. In addition to UAV use, the SuperStack Flex provides ample power for the FAA’s new Mosaic Light Sport category—offering sufficient output for a four-seat general aviation aircraft.

Final testing confirmed a specific power of over 1.2 kW/kg, with the system achieving continuous power above 150 kW and peak outputs over 175 kW during more than 100 hours of ground trials. Over the course of testing, the unit consumed 250 kilograms of hydrogen while maintaining consistent performance.

Hydrogen and fuel cell technologies are increasingly being recognised by armed forces globally for their energy density, low acoustic and thermal signatures, and operational flexibility. The systems’ quiet operation and reduced heat output make them particularly suited for intelligence, surveillance and reconnaissance (ISR) and other tactical missions.

Leveraging selective laser sintering (SLS) additive manufacturing, ZeroAvia streamlined production by reducing the SuperStack Flex’s component count by nearly half—cutting weight and volume by around 50 percent. Critical subsystems such as manifolds, thermal management and air compression have been consolidated from more than 200 individual parts to fewer than 100, enhancing reliability and reducing cost.

During the final test phase, the system powered ZeroAvia’s Propulsion Centre of Excellence in Everett, producing enough electricity to offset the facility’s own consumption.

ZeroAvia Founder and CEO Val Miftakhov said the achievement highlights how hydrogen-electric technologies are reshaping possibilities in both civil and defence aviation.

“Fuel cell systems are evolving to enable electric flight of unmanned aerial vehicles and a host of other vehicles,” he said. “With lower noise and heat signatures, lower maintenance costs, increased endurance and the ability to generate fuel locally, there are enormous capability benefits. We can generate an amazing amount of electrical power at a really low weight—opening up all kinds of possibilities for new vehicles in both the civil and defence arenas.”