In a significant advancement for sustainable aviation technology, Joby Aviation, a general aviation startup based in California, has successfully completed a non-stop flight with its hydrogen-electric air taxi demonstrator. The S4 eVTOL air taxi flew 523 miles (841 kilometers), producing only water as a by-product, showcasing the potential of hydrogen technology as a greener alternative to traditional gas-powered jets for mid-range regional travel.

Building on its successful battery-electric air taxi development program, Joby’s aircraft, which takes off and lands vertically, demonstrates how hydrogen can enable emissions-free travel without the need for a runway. This achievement underscores the viability of hydrogen technology for cleaner aviation solutions.

In September 2023, Joby’s H2FLY team set another world record by conducting the first piloted flight of a traditional liquid hydrogen-electric aircraft. This milestone is part of Joby’s broader technological program and results from the collaborative efforts of a small team at Joby and its wholly-owned subsidiary, H2FLY, based in Stuttgart, Germany.

Before its conversion to hydrogen-electric propulsion, the aircraft underwent over 25,000 miles of battery-electric testing at Joby’s facility in Marina, California. The demonstrator, based on Joby’s primary battery-electric aircraft, features a liquid hydrogen fuel tank and fewer batteries, maintaining the same airframe and overall architecture.

H2FLY developed a fuel cell system that generates heat, water, and power using hydrogen. 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), with vacuum jacketing to maintain 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.

Net-zero targets necessitate various sectors, including aviation, to transition to low-carbon-emitting options. Joby Aviation’s battery-electric and hydrogen fuel cell air taxi concepts aim to advance urban mobility in a more sustainable manner. “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.

Joby anticipates leveraging the design, testing, and certification work completed on its battery-electric aircraft to commercialize hydrogen-electric flights. The company plans to use 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. This vision reflects a promising future for clean aviation, driven by innovative technologies and sustainable practices.

By Impact Lab