H3X has reached a critical milestone in the dynamometer testing of their HPDM-250 integrated motor drive for electric aircraft. The unit successfully ran at 77% max torque and 90% max speed on their in-house dyno, producing 140 kW of shaft power. This puts their combined system-level specific power at 9.85 kW/kg achieved so far, which is 2–3X higher than state-of-the-art. The peak system-level efficiency measured with HBK data acquisition equipment during this testing was 96.4%. This round of testing was done with the direct-drive variant, and combined testing with the integrated gearbox is slated for later this summer. The inverter and motor thermal performance aligns well with simulation results at these power levels and the team will continue to push to 100% performance in coming months.

“We're absolutely thrilled with these early results and see a clear path to 12 kW/kg continuous within the next six months.” said Jason Sylvestre, Co-Founder and CEO of H3X. “The road to get this data has come with significant challenges, but I'm very proud of the pace at which the team has been able to identify and work through problems. The core technology we're proving out with the HPDM-250 forms the backbone of our competitive advantage and is directly scalable to our higher power motors. This will be a key enabler for widespread commercial electric aircraft on a massive scale.”

Within the last year, H3X has built four full-scale HPDM-250 prototypes, and is currently targeting completion of one more by the end of June. They will then build a small batch of pre-production units that will be delivered to development partners and customers towards the end of this year (2022) for bench testing and evaluation. Production is slated to begin in 2023.