Stralis Selects H3X to Develop MW-Class Electric Propulsion System for Hydrogen-Electric Regional Aircraft

By March 30, 2023 5   min read  (950 words)

March 30, 2023 |

Fuel Cells Works, Stralis Selects H3X to Develop MW-Class Electric Propulsion System for Hydrogen-Electric Regional Aircraft

Stralis and H3X have entered into a commercial agreement to develop and certify a 1.4MW multi-sector integrated motor drive for the Stralis B1900D-HE and SA-1 hydrogen-electric aircraft.

DENVER and BRISBANE, Australia, — Stralis Aircraft, the Australian startup pioneering hydrogen-electric aircraft to decarbonize commercial air travel, today announced they have selected H3X as their electric propulsion unit (EPU) supplier. They have entered into a commercial agreement to develop and certify a 10-kW/kg multi-sector integrated motor drive for the Stralis B1900D-HE and SA-1 aircraft. With H3X’s revolutionary motor technology and Stralis’ proprietary hydrogen fuel cell system, their aircraft will fly ten times farther than battery-electric alternatives at a lower operating cost than fossil fuel powered aircraft. The Beechcraft 1900 retrofit (B1900D-HE) will carry 15 passengers, have a range of 800 km plus reserves, and is slated to enter service in 2026 with a Supplemental Type Certificate (STC) from CASA and the FAA.

“Based on our extensive experience developing EPUs that have gone on to power a number of world first electric aircraft flights, we quickly recognized that H3X has developed a step change in EPU power to weight and efficiency” says Bob Criner, CEO of Stralis Aircraft. “Given the challenges we face in reducing hydrogen fuel cell weight, we need the lightest possible motors to make our aircraft commercially viable. From the outset, we felt that our company missions were well aligned and that H3X is the perfect partner to help us achieve our ambitious goals.”

“Stralis is onto something big and we’re very excited to support their mission of building 50,000 aircraft by 2050” says Jason Sylvestre, CEO of H3X. “We are both extremely passionate about developing sustainable electric aircraft to enable regional air mobility, and Stralis is developing compelling aircraft with the performance and economics required to realize this vision. Both companies are moving at lightspeed; we expect to have the detailed design of the EPU completed by Q4 this year and deliver first articles to Stralis for ground testing by Q3 of 2024.”

H3X is building integrated motor drives ranging from 30 kW to 3 MW, and are pushing the limits of materials and manufacturing processes to reach thermally continuous specific powers of >10kW/kg and best-in-class system efficiencies up to 97%. “Efficiency is often an overlooked metric in the optimization of these systems. A small increase in efficiency (e.g. +1%) can have an outsized impact on energy storage mass (- hundreds of kg)” says Jason Sylvestre. We have developed in-house architecture tools that use customer-provided aircraft sensitivities, analyze the specific power – efficiency trade space, and select a solution that results in the best vehicle-level performance in terms of CASK (Cost per Available Seat Kilometer), range, and payload.”

The unit H3X is developing for Stralis will be capable of 1.4 MW at a mass of 135 kg and will have cruise efficiency of 96.8 %. It will have 8 independent winding sets and inverters for fault-tolerant operation without compromise in performance. “There is nothing on the market with this level of power, efficiency, fault tolerance, and power density” says Jason Sylvestre.

“We’re seeing increased demand for our B1900D-HE aircraft, with $105M in LOIs signed with airline customers to date” says Bob Criner. Stralis specifically chose the B1900D aircraft due to the pressurized cabin, 270 knot cruise speed and large internal cabin volume, allowing sufficient onboard green hydrogen storage to meet customer range requirements. “The retrofit approach is a practical first step to get a product into the market as quickly as possible and help spark the kind of innovation our industry needs to achieve net zero by 2050”.

“The product that really excites our customers is the SA-1 aircraft, which we’re targeting to be the world’s first clean-sheet hydrogen electric commercial aircraft” says Criner. The SA-1 will offer a 40% reduction in operating costs compared to the current aging fleet of 50 seat turboprops, unlocking new regional routes that were previously unprofitable. “We found the H3X product portfolio to be well suited to our aircraft programs”.

Over the next 9 months, H3X and Stralis will work together to perform ground and flight testing of the HPDM-250 EPU installed on Stralis’ Beechcraft Bonanza flying test bed. “We want to get an aircraft flying as quickly as possible to accelerate our learnings and firmly establish hydrogen electric propulsion as the optimum solution for emission-free flight”, says Bob Criner.

  Read the most up to date Fuel Cell and Hydrogen Industry news at FuelCellsWorks


Founded in 2020 by a team of multidisciplinary engineers, H3X is an advanced technology and electric motor manufacturing company based in Denver, Colorado. Their team brings together driven minds from automotive, aerospace, and motorsports with deep knowledge in electric machines and power electronics. They are heavily vertically integrated: designing, manufacturing, and testing their integrated motor drives under one roof at their 17,000 sq-ft headquarters facility. The mission of the company is to become the world’s leading supplier of aviation-grade electric propulsion systems by 2030 to enable a large-scale revolution in aircraft electrification and regional air mobility. For more information, visit

ABOUT Stralis

Stralis makes emission free hydrogen electric aircraft. Founded in 2021 in Brisbane, Australia, with the goal to decarbonize air travel, improve passenger experience and create a world class aircraft manufacturer. Stralis sees green hydrogen as a fundamentally clean solution that is carbon-free, lightweight and cost effective. Their team has over 85 years of aerospace experience, having developed, flight tested and certified aircraft at Google X, magniX, Heart Aerospace, Ampaire, Airbus, Bombardier and Gulfstream. They have $105M in aircraft LOIs from airline customers and are funded by Liquid2 Ventures, Collab Fund, Chris Golda and Y Combinator (W23). For more information, visit


Author FuelCellsWorks

More posts by FuelCellsWorks
error: Alert: Content is protected !!