Heart Aerospace has completed a 27-minute flight of its X1 demonstrator aircraft at Plattsburgh International Airport in New York, proving that commercial-scale electric flight is achievable using battery power alone.
The test flight took place on August 12, with the 11-ton aircraft drawing more than one megawatt of power from its electric propulsion system across a 32-metre wingspan. The X1 relied entirely on electric propulsion through every phase of the flight, including taxiing, takeoff, climbing, maneuvering, and landing.
The successful test demonstrated that aircraft built for future commercial passenger services can operate solely on batteries. However, the Gothenburg-headquartered manufacturer is pursuing a different powertrain design for its upcoming commercial regional airliner, the ES-36, which will combine battery power with liquid fuel turbogenerators.
Heart Aerospace is a Swedish aviation developer focused on decarbonising regional transport through electric propulsion. Plattsburgh International Airport, located in upstate New York near the Canadian border, serves as an international testing facility for aerospace innovation.
Dual power architecture for regional flights
The planned Heart Aerospace ES-36 features two propellers driven directly by electric motors, establishing a fully electric propulsion architecture. To overcome battery energy limitations on longer routes, the aircraft includes onboard turbogenerators that burn liquid fuel to generate electricity when battery reserves are insufficient.
During flight, the electricity produced by the turbogenerators powers the motors that rotate the propellers. This dual configuration addresses the differing energy demands encountered during different stages of regional flight.
Takeoff and initial climb demand several megawatts of power, but this peak requirement lasts for a relatively short duration. Cruise flight requires lower instantaneous power, but the aircraft must sustain that energy over extended periods.
While current battery technology delivers high power output effectively, it remains far behind liquid fuels in terms of energy density per unit of weight. The hybrid architecture of the ES-36 utilizes batteries for short flights while engaging turbogenerators as flight distances increase, ensuring the airliner is not restricted strictly to battery range limits.
Evolution of Heart Aerospace aircraft designs
The current architecture of the ES-36 represents the latest phase in a series of design revisions carried out by Heart Aerospace. The company initially launched its regional aviation program with the ES-19, which was conceived as a pure battery-electric aircraft.
In 2022, the manufacturer adjusted its strategy by introducing the 30-seat ES-30, incorporating turbogenerators into the system to extend operational range. Heart Aerospace shifted direction again in 2024, planning for the ES-30 to feature two battery-electric propellers alongside two conventional turboprop engines.
That 2024 design eliminated energy conversion losses associated with generating electricity via turbines to produce mechanical power, though it required managing two distinct propulsion systems on a single airframe. The subsequent ES-36 design returns to a unified electric driveline where both propellers are continuously driven by electric motors.
Under the ES-36 configuration, turbogenerators serve exclusively to supply electrical energy to the motors when required. This keeps the primary propulsion system fully electric while allowing the source of electricity to vary based on flight requirements. By working around existing battery constraints rather than waiting for battery breakthroughs, Heart Aerospace aims to commercialise its technology faster than competing developers.
Range specifications and battery performance
Heart Aerospace currently projects a commercial flight range of approximately 200 kilometres for the ES-36 when operating on battery power alone. When the onboard hybrid system is utilized, total flight range increases to up to 1,200 kilometres.
According to Heart Aerospace, offering an aircraft that can engage turbines for longer routes provides regional airlines with significantly greater operational flexibility. Consequently, the company has focused its ongoing development work on this hybrid approach.
Heart Aerospace has not yet disclosed detailed specifications regarding the production ES-36 battery system, including its specific chemistry, total storage capacity, or system-level specific energy figures. The full operational capability of the aircraft will become clearer once those technical details are released.
Laboratory measurements of cell-level energy density do not translate directly into usable aircraft battery packs. Flight-ready battery systems must meet stringent performance criteria, including supplying high takeoff power, enduring numerous charge and discharge cycles, providing efficient thermal management, and ensuring safety during thermal runaway events. Achieving higher energy density at the individual cell level does not automatically guarantee a proportional increase in aircraft flight range.
Long-term upgrades and environmental impact
The propulsion design chosen by Heart Aerospace offers a key operational advantage for airline fleets. Because the propellers of the ES-36 are driven exclusively by electric motors, future advancements in battery technology will allow airlines to extend the aircraft range without redesigning its core propulsion infrastructure.
As battery cells with higher energy density become available, reliance on onboard turbogenerators will decrease, expanding the distance over which pure electric flight remains economically viable. Given that commercial passenger aircraft typically remain in service for several decades, individual ES-36 airframes are likely to undergo multiple battery pack replacements throughout their operational lifespan.
Upgrading battery packs over time will enable the same airframes to complete a higher proportion of scheduled flights without burning liquid fuel. Evaluating the environmental impact of the ES-36 requires looking beyond simple electric or hybrid designations.
On shorter routes flown entirely on battery energy, fuel consumption is eliminated completely. Despite its hybrid architecture, the aircraft can operate with a very low carbon footprint when deployed on short regional sectors.
