On 11 July 2024 the leading eVTOL company Joby Aviation annouced that one month agao they have flown a modified S4 tilt-rotor eVTOL converted to liquid hydrogen fuel cell electric 523 miles (841km) on one tank of liquid hydrogen.

The landmark test flight, believed to be the first forward flight of a vertical take off and landing aircraft powered by liquid hydrogen, was completed last month using a converted Joby pre-production prototype battery-electric aircraft fitted with a liquid hydrogen fuel tank and fuel cell system. It landed with 10% of its hydrogen fuel load remaining. The flight was supported by the Agility Prime project of the US Air Force.

Joby’s hydrogen-electric demonstrator is part of the Company’s future technology program and is the result of several years of collaboration between a small team at Joby and H2FLY, Joby’s wholly-owned subsidiary based in Stuttgart, Germany. The converted aircraft previously completed more than 25,000 miles of testing as a battery-electric aircraft at Joby’s base in Marina, CA.

Using the same airframe and overall architecture as Joby’s core, battery-electric aircraft, this demonstrator features a liquid hydrogen fuel tank, designed and built by Joby, which stores up to 40 kilograms of liquid hydrogen, alongside a reduced mass of batteries. Hydrogen is fed into a fuel cell system, designed and built by H2FLY, to produce electricity, water, and heat. The electricity produced by the hydrogen fuel cell powers the six electric motors on the Joby aircraft, with the batteries providing additional power primarily during take-off and landing.

Joby’s H2FLY team used similar technology to complete another record-breaking flight in September 2023, when they flew the world’s first piloted flight of a conventional liquid hydrogen-electric aircraft using their fuel cell technology.