A Hard Cell by Any Measure

Stuttgart-based H2Fly, a wholly-owned subsidiary of U.S. eVTOL concern Joby Aviation founded for purpose of researching, building, and testing hydrogen-electric aircraft powertrains, announced on 24 April 2023 that it has successfully passed liquid hydrogen on-ground filling tests of a newly-developed liquid hydrogen tank integrated into its HY4 aircraft—a four seat hydrogen fuel-cell powered contraption based on a Taurus G4.

The testing initiative was undertaken in support of Europe’s HEAVEN (High powEr density FC system for Aerial Passenger VEhicle fueled by liquid hydrogeN) project, a consortium of five partner entities convened to demonstrate the feasibility of liquid, cryogenic hydrogen fuel-cell aircraft powertrains. The HEAVEN consortium comprises Spain’s Ayesa Foundation; France’s Air Liquide Advanced Technologies (ALAT); Germany’s Elringklinger, DLR, H2FLY; and Slovenia’s Pipistrel Vertical Solutions.

The liquid hydrogen filling procedure and testing took place in preparation for upcoming coupling tests in which the aforementioned liquid hydrogen storage system will be coupled with a fuel-cell system to form a complete hydrogen-electric powertrain. H2FLY conducted the test campaign in cooperation with Air Liquide on the former’s Campus Technologies Grenoble, in Sassenage, France.

The achievement in liquid-hydrogen management follows a November 2022 announcement in which H2FLY set forth it had commenced mechanical integration of Air Liquide’s liquid hydrogen tank into the HY4 aircraft following successful vibration and leakage testing of subject tank in September 2022.

H2FLY co-founder and CEO Professor Dr. Josef Kallo stated: “The successful on-ground filling tests today mark the next milestone in our pursuit to doubling the range of our HY4 aircraft. It is a critical step for our upcoming flight test campaign this summer, which will demonstrate the feasibility of liquid hydrogen as a fuel for medium and long-haul flight.”

After more than a decade of research, testing, and refining, H2FLY’s HY4 aircraft took flight in 2016. Since the machine’s maiden flight, the platform has attained numerous milestones, including:

• In 2020 H2FLY was granted a permit to fly the latest generation of the HY4 aircraft, which featured a fully-redundant powertrain architecture. Over the course of more than one-hundred take-offs and landings, the company successfully demonstrated the feasibility of the aircraft’s hydrogen-electric propulsion system.
• In 2021 H2FLY signed a strategic partnership with aircraft manufacturer Deutsche Aircraft by which the two companies will work together to fly a CS25 class aircraft (multi-engine jets and turbo-props having more than nine passenger seats and/or weighing in excess of 5700-kilograms/12,566-pounds) powered by H2FLY’s hydrogen fuel cell technology. The climate-neutral regional aircraft demonstrator is expected to fly in 2025
• In 2022, H2FLY completed a cross-country flight, from Stuttgart to Friedrichshafen, Germany, covering 67-nautical-miles and marking the first time a hydrogen-powered passenger plane has flown between two commercial airports
• Also in 2022, H2FLY set what is believed to be a world altitude record for a hydrogen aircraft, by flying its HY4 at 7,230 feet MSL.

By successfully passing the battery of liquid hydrogen on-ground filling tests, the HEAVEN consortium has demonstrated expertise in liquid hydrogen refueling operations and aircraft onboard liquid hydrogen handling. H2FLY remains among a small number of aerospace entities in the vanguard of hydrogen-powered flight. The company’s progress to date heralds the emergence of hydrogen fuel-cells as a practical near-future alternative power source for private and commercial aircraft.

FMI: www.h2fly.de