H2Fly completes filling tests of liquid hydrogen tank


H2Fly has successfully filled and tested on the ground a liquid hydrogen tank for use in its HY4 aircraft.

The Stuttgart, Germany-based is developing hydrogen fuel cell-based powertrains for use in aircraft and has been flying HY4 with pressurized gaseous hydrogen since 2016. HY4 is a four-seat aircraft based on the Pipistrel Taurus G4.

H2Fly expects the use of liquid hydrogen (LH2), which is more challenging to handle and store than gaseous hydrogen, to at least double the HY4’s range from 450 to 900 miles.

The integration of a liquid hydrogen tank into an aircraft and the successful filling tests is a significant milestone for the program and a world first according to HY4.

The work is being carried out as part of an EU-funded project called HEAVEN that involves several partners and aims to demonstrate the feasibility of using liquid, cryogenic hydrogen-powered fuel cell powertrain in aircraft.

The liquid hydrogen storage system was designed and supplied by Air Liquide. The filling procedure took place in preparation for forthcoming coupling tests in which the liquid hydrogen storage system will be coupled with the fuel cell system to form a complete hydrogen-electric powertrain.

filling test

The test campaign was carried out at Air Liquide’s Campus Technologies Grenoble, France (Image: H2Fly)

Josef Kallo, co-founder and CEO of H2FLY said, “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.”

The LH2 tank passed the vibration and LH2 leakage tests in September 2022 and was fitted into the aircraft in November.

Last year H2Fly achieved an altitude record for a hydrogen fuel cell-powered aircraft of 7,320ft. The company is also working with Munich-based Deutsche Aircraft to convert Dornier 328 regional aircraft to run off hydrogen and plans to make the first test flights in 2025.

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Ben has worked as a journalist and editor, covering technology, engineering and industry for the last 20 years. Initially writing about subjects from nuclear submarines to autonomous cars to future design and manufacturing technologies, he was editor of a leading UK-based engineering magazine before becoming editor of Aerospace Testing in 2017.

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