French training aircraft manufacturer Elixir Aircraft plans to fly a turboprop-powered version of its two-seater by year’s end, as part of its road map to reduce emissions by enabling the first use of sustainable aviation fuel (SAF) and later liquid hydrogen.
An Elixir is on display here at the Paris Air Show lab with a mockup of the TP-R90 regenerative turboprop, from French engine-developer TurboTech, installed in place of the production-standard Rotax 912iS piston engine.
Elixir is exhibiting at Paris buoyed by a major order for the U.S. market. Scottsdale, Arizona-based airline pilot training academy Sierra Charlie Aviation has ordered 100 Elixir trainers with an option for 50 more. Elixir’s CS-23-certified aircraft has a full glass cockpit.
The turboprop-powered Elixir is being developed under a two-part program funded by France’s Council for Civil Aeronautical Research—or Corac—with funds from the government’s France Relance post-pandemic stimulus program.
Under the second part of the program, Elixir is working with Air Liquide, Daher, Safran and TurboTech to ground test a zero-emission version of the turboprop fueled with cryogenic liquid hydrogen. “On the way to hydrogen we need to put in a turbine engine burning SAF,” says Cyril Champenois, Elixir’s co-founder.
The Rotax 912iS already is more efficient than earlier versions with lower emissions, but its gasoline fuel is expected to become harder to find as ground transportation electrifies, so Elixir wants to move to using jet fuel. Using SAF could then reduce life cycle-CO2 emissions by 90%, Champenois says.
The challenges with using a turbine are fuel consumption and cost. But TurboTech’s engine is a regenerative turbine that is equipped with a heat exchanger that recovers the heat from the exhaust gases and reinjects it into the combustion chamber, leading to a significant fuel burn reduction.
Elixir expects the turboprop to be competitively priced, with lower operating costs due to a projected 3,000-hr. time between overhaul and no need for the 100-hr. inspections required for piston engines. Commercial pilots will also be able to train at the outset on a turbine aircraft, he says.
The company plans to make its training aircraft available with 100-, 140- and 160-shp versions of the turboprop within two to four years. But Champenois expects it could take two or three decades before a liquid-hydrogen-powered version becomes operational in flight schools.
