From Brisbane to the White House

Deep Dive

When Stralis Aircraft founders got the call last month from former Australian PM and current ambassador to the US, Kevin Rudd, to visit the White House as part of a select group of leading Australian cleantech start ups they were shocked.

Despite being a Winter 2023 Y Combinator graduate (often a shoe in with investors), Stralis, to its misfortune, emerged into a cold funding environment in April this year. The crash of Silicon Valley Bank – the 16th largest US bank before its collapse – which specialised in financing and banking for venture-backed startups, left capital markets temporarily cautious. Stralis raised just $2m in pre-seed funding after graduation from Y Combinator, Liquid2 Ventures, Collab Fund, Schox, Climate Capital and Chris Golda.

Undeterred, co-founders Bob Criner and Stuart Johnstone (pictured below left and right) put that $2m to good use. The firm has upped the order book for its B1900D-HE system to $210m across nine airlines in the US, Europe, Australia and New Zealand, including launch customer Skytrans Airlines – plus, now publicly sharing it has letters of intent with Penjet and Air Frontier.


As well as completing initial high temperature hydrogen fuel cell testing, Stralis has also been working with its two Beechcraft Bonanza test aircraft – aka Bonnie and Clyde. Bonnie – undergoing preparation for initial test flights next year – is the flying half of the pair, whilst Clyde is the ‘iron bird’ ground testbed. In late summer, Clyde was fitted with H3X’s HPDM-250 electric motor, the first shipped out by the US motor OEM.

Early hardware-in-the-loop testing of the motor has been “highly successful, the product has been very easy to integrate,” Criner tells us. Stralis uses software programme, Simulink to create detailed system simulation models of its aircraft and hydrogen electric propulsion system. The team then perform Software-in-the-Loop (SIL) and Hardware-in-the-Loop (HIL) testing using a Speedgoat real time computer.

“You’ve probably heard of a hardware-in-the-loop test setup. Essentially you create a simulated model of your propulsion system,” says Criner. “We use Simulink and in that you’ve got a model of the motor, model of the fuel cell and a model of the liquid hydrogen tank. The beauty of the HIL setup is you can take pieces of that model out of the simulation and into the real world, because the HIL interfaces mimic the real interfaces that component will see when it is installed in the airplane. This is an essential system development test process that we are following here.” It allows Stralis to test how the system responds to certain potential failures without damaging expensive hardware. By taking it a step further and fitting the HIL test setup within Clyde’s airframe means Stralis can also get a head start on how their systems will perform in the specific setup they will initially fly in, accelerating their development timelines.

Technology readiness

Criner puts Stralis’ system between technology readiness levels (TRL) three and five. TRLs are a type of measurement system used to assess the maturity level of a particular technology. “It depends on what part of the system you are talking about,” says Criner. “Integration of the motor into our system is around level five. But the hydrogen piece of the system, we are currently working on our safety standards and getting approval from the airport to bring hydrogen on site and start testing with it, so that is less mature. We have fuel cells in our lab and we are starting to build our fuel cell system, but it is not running yet. All tests have been performed with a DC power supply to date.”

Elsewhere, Stralis launched the Hydrogen Flight Alliance at Brisbane Airport in June, which brings together leading Australian organisations to develop the hydrogen flight ecosystem required to enable operation of emission-free aircraft. “One of the main concerns we hear from investors is where are you going to get cheap green hydrogen at airports, the cost of infrastructure upgrade is way too much and the timing is uncertain. So we created this hydrogen flight alliance that includes a few airports across Australia, airlines, us aircraft makers and green hydrogen logistics companies like BOC (owned by German gas multinational Linde). The key of the alliance is that we bring all of the right people together to advance the hydrogen ecosystem required to support our airplanes,” says Criner.

The White House

Since graduating YC earlier this year, the Stralis team has grown to 10 strong, with over 150 years of combined aerospace, electric propulsion and hydrogen experience, including the person who wrote the book on hydrogen fuel cells, says Criner. Nevertheless, to be selected for the visit to Washington DC was a curveball. The best kind, he says. “It was unbelievable. Stuart and I were offline for a few days and when I logged back in I saw the email from the former prime minister of Australia and my first reaction was this can’t be real. But we got another one inviting us to DC alongside current Australian Prime Minister Anthony Albanese, and we had to go. It’s clear people are recognising what we are doing here at Stralis, and that the world needs our emission free aircraft.”  

The Aussie PM was on an official state visit to the US addressing topics including the Climate, Critical Minerals and Clean Energy Transformation Compact signed back in May. “This includes clean hydrogen which will fuel our aircraft and the clean energy needed to produce green hydrogen. Standing on the south lawn of the White House listening to Biden and Albanese speak about how our two countries will lead the world in cleantech convinced me that there’s no better time to be building an innovative Australian start up working to decarbonise air transport,” adds Criner.

Seed round launch

The visit to the White House coincided with the launch of Stralis’ seed round. Post-visiting Washington DC the team is in the US to meet investors. “We’re currently in San Francisco kicking off our seed round, which will allow us to achieve first flight of Bonnie, our Bonanza technology demonstrator aircraft next year, as well as advance the design of our 15-seat retrofit and 50-seat clean sheet aircraft products,” says Criner. “We’re targeting an $8m seed round to push on with our ground test programme, achieve first flight and also support the hydrogen flight alliance to work on solving the ecosystem problem.”

Stralis originates from Brisbane, at the heart of Australia’s Sunshine State. Queensland is a long way (over 9,000 miles) from the US capital. It is almost as far from Linde’s HQ in Germany. Overcoming the challenges to building a hydrogen ecosystem is going to require helping hands from many corners of the globe.

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