Heart Aerospace has received a $2.9 million award from the Federal Aviation Administration (FAA) to advance development and testing of the hybrid-electric propulsion system for its 36-seat ES-36 regional aircraft.
The award, made under Phase IV of the FAA’s Continuous Lower Energy, Emissions, and Noise (CLEEN) programme, will support a 24-month research and demonstration project valued at $5.8 million, including Heart’s matching contribution. The project, known as Hybrid Propulsion Environmental Readiness (HYPER), will focus on the aircraft’s turbogenerator technology and its integration with the wider propulsion system.
The ES-36 will use a series-hybrid architecture in which megawatt-class turbogenerators installed in each of the two propulsion nacelles generate electricity during flight. This electricity will supplement battery power, extending the aircraft’s range beyond its all-electric capability.
Testing will begin on the ground, assessing how the turbogenerators, batteries and electric motors operate together across different operating modes. The programme will then progress to demonstration flights using Heart’s pre-production aircraft, which is scheduled for its first flight in 2028. Data gathered during testing will cover energy consumption, fuel burn, emissions and noise, supporting the ES-36’s certification programme and informing the FAA’s evaluation of hybrid-electric aircraft technologies.
The award builds on earlier FAA support through the Fueling Aviation’s Sustainable Transition (FAST) programme, which funded development of Heart’s Total Hybrid Electric Management and Integration System (THEMIS). The system coordinates the electric motors, turbogenerators and batteries during flight.
Heart is targeting an all-electric range of 125 miles and a hybrid range of up to 745 miles, both plus reserves. The hybrid system is designed to use electricity generated from conventional Jet A fuel or sustainable aviation fuel (SAF) for longer regional missions, while enabling battery-only operation on shorter routes.
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For the aerospace industry, the project will generate technical data on hybrid propulsion integration, system performance and testing requirements. These findings could also inform future engineering, maintenance and certification considerations as hybrid-electric aircraft move towards commercial service.
The award follows several milestones for Heart in 2026, including the first flight of its X1 demonstrator, the unveiling of the ES-36 production aircraft and a purchase agreement with JSX for up to 100 aircraft.
