ABOVE: Alternative propulsion systems are being developed by Elixir, with SAF and hydrogen powering a TurboTech PT90 powerplant. 

Elixir Aircraft has unveiled a prototype of its new ‘green’ aircraft, projected to be powered by either sustainable aviation fuel (SAF) or hydrogen, during the Paris Air Show.

While the Rotax-powered variant of their two-seat, low-wing carbon-fibre airframe has already sold around 70 units, plans for the latest two iterations – projected to be powered by SAF or hydrogen – are already being conceived. Although the full maturity of such technologies may be fifteen years away, explained co-founder Cyril Champenois, it’s never too early to commence the substantial research and development associated with such an undertaking. “We have the building bricks, but we need to integrate,” he elaborated.

Champenois also detailed Elixir’s strategy behind pursuing the development of two fuel systems simultaneously, noting that it’s “always a balance” and that he’s “quite comfortable” with both the SAF and hydrogen plans being projected. Keeping options open regarding maturing technologies, Elixir are “not reliant on any one”. Furthermore, with the fuel system being the only noticeable difference between variants, to develop both concurrently seems a “very efficient solution”.

The SAF-powered version is the first of the two ‘greener’ variants, which, much like conventional-fuelled Rotax aircraft, is projected to have an endurance of five to six hours. However, as doubts remain as to the ultimate scalability of SAF, a hydrogen-powered aircraft is also under development. Collaborating with French company Air Liquide for fuel tank solutions, tests have already shown successful storage of hydrogen for up to three days, and the variant is projected to have a duration of around two to three hours.

However, unlike others in the sector, it’s apparent that Elixir do not intend to pursue electric propulsion systems alongside their alternative green strategies. “Just look at the numbers,” explains Champeonis, highlighting that endurances available right now (even combined with optimistic projects) are still “far away from what SAF can do”.

It’s hoped the SAF-fuelled aircraft will fly towards the end of the year or early 2024, while collaborative efforts to develop the cryogenic hydrogen propulsion system – supported by France’s CORAC civil aviation research council, Safran, Daher and Air Liquide – continue.