Heart Aerospace Wins FAA CLEEN Phase IV Award to Develop ES-36 Hybrid-Electric Turbogenerator
Why It MattersFederal backing for a series-hybrid regional aircraft's certification data signals the FAA is building an evaluation path for hybrid-electric propulsion that could shape how the wider industry certifies such designs.
Heart Aerospace announced Monday an award from the Federal Aviation Administration (FAA) under Phase IV of the agency's Continuous Lower Energy, Emissions, and Noise (CLEEN) public-private partnership program. With an equal cost share from Heart, the award supports a $5.8 million, 24-month R&D and demonstration project, called Project HYPER (Hybrid Propulsion Environmental Readiness).
The funding will advance development and testing of a Heart turbogenerator for the ES-36's series-hybrid propulsion system. Each of the aircraft's two propulsion nacelles will house a megawatt-class turbogenerator that produces electricity in flight, extending range beyond what batteries alone can provide. Heart will develop and test it on its pre-production aircraft, scheduled to make its first flight in 2028. The project begins with ground testing of how the turbogenerator, batteries and electric motors work together in different operating modes, then moves to demonstration flights aboard the pre-production ES-36. It will generate data on energy use, fuel burn, emissions and noise to support ES-36 certification and inform the FAA's approach to certifying hybrid-electric aircraft more broadly.
The award extends FAA support previously provided through the Fueling Aviation's Sustainable Transition (FAST) program, which funded the Total Hybrid Electric Management and Integration System (THEMIS), the control architecture that coordinates the ES-36's electric motors, turbogenerators and batteries. Together, the turbogenerators and THEMIS will let the ES-36 fly on battery power alone on short-haul routes and supplement it with electricity generated from Jet A and sustainable aviation fuel (SAF) on longer regional missions. Heart is targeting an all-electric range of 125 miles and a hybrid range of up to 745 miles, both plus reserves.
Ben Stabler, Heart's Chief Technology Officer, said the FAA's continued partnership will accelerate development of this key element of the ES-36's hybrid-electric powertrain. Cole Randle, Head of Corporate Affairs, said Heart would advance the ES-36 toward flight demonstration while generating knowledge to help the broader industry build, test and certify hybrid-electric aircraft.
The award adds to Heart's 2026 milestones, which include the first flight of its X1 demonstrator, the unveiling of the 36-seat ES-36 production aircraft, and a purchase agreement with JSX for up to 100 ES-36 aircraft. Heart is a Los Angeles-based electric aircraft manufacturer and reports over $9 billion in customer commitments from carriers including United Airlines, Air Canada and JSX.
