Stralis Aircraft is advancing its plans for hydrogen-powered aircraft, starting with a technology demonstrator based on a Bonanza A36 model with which it is aiming to start flight tests by the end of 2025. The Australian start-up intends to apply for a supplemental type certificate (STC) covering the conversion of the single-engined aircraft. It also has longer-term plans to convert the larger Beech 1900D utility aircraft and to develop a clean-sheet regional airliner called the SA-1-HE.

In late March, Brisbane-based Stralis announced a partnership with New Zealand company Fabrum, which will develop and test liquid hydrogen storage tanks and a fuel system for its hydrogen-electric propulsion system. The companies have received support from Ara Ake, which is New Zealand’s future energy center.

Stralis co-founder and chief technology officer Stuart Johnstone said the STC application for the Bonanza conversion will be made in 2026 if there is sufficient demand, adding that the company has already logged expressions of interest. In December, it conducted the first ground tests with the hydrogen propulsion system on what it refers to as the Bonanza A36-HE at Brisbane International Airport, and has said that it could start deliveries in 2027.

Work on the 15-seat B1900-HE model is expected to start after the initial Bonanza flight tests as Stralis works toward a target entry into service date in 2030. Australian regional airline Skytrans is the launch customer for this conversion project.

The SA-1-HE would be a 50-seat airliner with a projected range of up to 3,000 kilometers (1,620 nm). According to Stralis, work for this program could begin in 2028 with an anticipated entry into service in 2037.

Lightweight, Scalable Fuel Tanks

Fabrum is developing wing-tip fuel tanks for the Bonanza A36-HE, with each holding 13 kilograms (about 28.7 pounds) of liquid hydrogen. Using lightweight composite materials, the Christchurch-based company said it has the capability to scale up the size of the tanks to store up to 500 kilograms of the fuel. The B1900D-HE aircraft would have a pair of tanks in the fuselage holding 210 kilograms of liquid hydrogen, and the SA-1-HE would carry 1,100 kilograms.

According to Fabrum, its patented triple-skin tanks will support reduced refueling times and loss of gas through boil-off. The vaporiser for converting the liquid hydrogen into gas is built into the composite tank, which Stralis is integrating with its high-temperature proton exchange membrane fuel cells. The propulsion system requires the gas to be heated to 180 degrees C and the tank is pressurized to 3 bars.

With support from Ara Ake, Fabrum is also working on the process for distributing green liquid hydrogen, produced using renewable energy sources, to airports. “Our hydrogen liquefier provides readily available liquid hydrogen onsite, allowing the capability to access the critical fuel source to prove and test the tanks and fuel system we are developing for Stralis and their fixed-wing fuel-cell electric aircraft,” said Fabrum’s managing director, Christopher Boyle.

Stralis has started working with Australia’s Civil Aviation Safety Authority on the certification process for its propulsion systems. The company intends to make the technology available to other aircraft manufacturers for experimental applications from mid-2026 and for certified commercial applications from 2028. It said it has signed letters of intent with prospective aircraft operators in Australia, New Zealand, Asia, Europe, and the U.S.