iStock/Just_Super Hydrogen fuel cells extend eVTOL range The electrochemical power source offers numerous advantages over batteries, says a leading propulsion expert. By Mark Huber Hydrogen fuel cells solve two critical problems that hinder current battery applications in electric vertical aircraft: range and weight, according to Dr. Anita Sengupta, founder and CEO of Hydroplane, an award-winning start-up developing hydrogen fuel cell powerplants for rotary- and fixed-wing aircraft. “When you’re lifting a battery off the ground, you don’t have much payload potential left. There is an inflection point where it makes sense to go to hydrogen fuel cell technology versus batteries,” Sengupta said during the Hydrogen Propulsion Panel on Jul. 19 at the 20th Annual Electric Aircraft Symposium in Oshkosh, Wisconsin. “That’s the inflection point that we passed and that we’re working on.” With its higher energy density—35,000 watts per kilogram versus 200 watts for lithium batteries, Hydroplane’s hydrogen fuel cell propulsion system packs more fuel per pound and provides the same or better range as hydrocarbon combustion engines. In July 2025, as part of the US Army’s Small Business Innovation Research (SBIR) program, Hydroplane proved its system’s potential for vertical aviation. The company built and tested a rotary-wing test stand representative of light helicopters (23-ft. diameter) that included its integrated hydrogen fuel cell electric propulsion system. It ran stable at operational speeds. “Our second product in the Phase 2 Army [SBIR] contract is a Rolls-Royce 250 [engine] replacement system for a four-seat helicopter,” said Sengupta, an aerospace engineer with 22 years of experience, including 16 years at NASA Jet Propulsion Laboratory and three years at Boeing Space and Communications. Based on its success, Hydroplane is developing a product to replace the Lycoming IO-360 aviation engine, but the technology is scalable all the way up to regional aircraft, says Sengupta. In addition to range and weight, hydrogen fuel cells offer advantages such as no recharge delays—refueling only takes five minutes—and a long lifespan. “They’re made of different line replaceable units, so you can actually increase the time between overhaul, and ultimately reduce operational expenses for an aircraft operator,” said Sengupta, who holds a commercial pilot’s license and high-performance aircraft, complex aircraft, and instrument ratings. Hydroplane is also developing a hydrogen fueling station for a state government customer. “It is a pretty small one, 100-kilogram capability. An FBO [fixed base operator] could use it, for example, to be able to fuel the aircraft that we provide,” she said. “It was important for us to be able to show that this is a realistic solution moving forward.” Mark Huber is an aviation journalist with more than two decades of experience in the vertical flight industry.
