Hydrogen-powered air taxi sets record 523-mile trip, emits just water steam

In a push for cleaner forms of aviation technologies, a general aviation startup has announced the successful non-stop flight of its hydrogen-electric air taxi demonstrator.

California-based Joby Aviaiton’s S4 eVTOL air taxi traveled 523 miles (841 kilometers), producing only water as a by-product.

Hydrogen technology is being promoted as a more environmentally friendly alternative to traditional gas-powered jets for mid-range regional travel.

Building on the firm’s successful battery-electric air taxi development program, the aircraft takes off and lands vertically. It also shows how hydrogen has the potential to enable emissions-free, regional travel without the need for a runway.

Using their fuel cell technology, Joby’s H2FLY team achieved another world record in September 2023 when they conducted the first piloted flight of a traditional liquid hydrogen-electric aircraft.

Hydrogen-electric propulsion

As a component of the company’s upcoming technological program, the firm’s hydrogen-electric demonstrator is the outcome of efforts from a small team at Joby and H2FLY, Joby’s wholly-owned subsidiary situated in Stuttgart, Germany.

Prior to the conversion, the aircraft underwent over 25,000 miles of battery-electric testing at Joby’s facility in Marina, California.

This demonstrator, which is based on Joby’s primary battery-electric aircraft, has a liquid hydrogen fuel tank of liquid hydrogen and fewer batteries because it has the same airframe and overall architecture. H2FLY created and built a fuel cell system that uses hydrogen to generate heat, water, and power.

The modification included adding a cryogenic fuel tank capable of storing up to 88 lbs (40 kg) of liquid hydrogen at 22 Kelvin (-420°F, -251°C). The tank’s vacuum jacketing maintains a safe ambient surface temperature.

Hydrogen from the tank powers the H2Fly-developed ‘H2F-175’ fuel cell system, which generates electricity through an electrochemical reaction with oxygen from the air, producing water and heat as by-products.

The electricity generated by the fuel cell serves as the primary power source for the aircraft’s six rotors during flight, while a small battery assists mainly during takeoff and landing. Additionally, the fuel cell system recharges this battery.

Future of clean aviation

Net zero targets have required various sectors, including aviation, to transition to less carbon-emitting options. Firms like Joby Aviaiton’s battery-electric and hydrogen fuel cell air taxi concepts aim to advance urban mobility in a more practical and sustainable way.

“Clean hydrogen has the potential to help decarbonize our aviation system for decades to come. Regional air mobility innovation provides a clear opportunity to incorporate clean hydrogen into the future of transportation,” said Jeff Marootian, Principal Deputy Assistant Secretary for Energy Efficiency and Renewable Energy, in a statement .

Most of the design, testing, and certification work that Joby Aviation has completed on its battery-electric aircraft is applicable to commercializing hydrogen-electric flights.

According to the firm, the company anticipates using the same landing pads, operations team, and ElevateOS software to support the commercial operation of both battery-electric and hydrogen-electric aircraft.

“Imagine being able to fly from San Francisco to San Diego, Boston to Baltimore, or Nashville to New Orleans without the need to go to an airport and with no emissions except water,” said JoeBen Bevirt, Joby founder and CEO.

Joby asserts that their recent flight marks the pioneering forward flight of a liquid hydrogen-fueled VTOL, setting a record by default. They envision liquid hydrogen’s potential unlocking capabilities far beyond, with expectations of over 900 miles (1,500 km) range for aircraft like the H2Fly HY4 fixed-wing model.