FLYING Magazine
Hybrid-electric regional aircraft developer Heart Aerospace has pivoted to a new flagship aircraft intended to deliver 20 percent more passenger and payload capacity and better economics than its previously announced ES-30, with JSX placing a deposit-backed order for the clean-sheet design.
The company’s new ES-36 will have 36 seats, compared to 30 on its previous flagship design, and shift from four nacelles and propellers to two, which Heart said will reduce drag, simplify the integration of the hybrid-electric propulsion system, shrink the size of the wing, and lower maintenance costs. Like the ES-30, the ES-36 targets 40 percent lower operating costs versus legacy regional aircraft.
The ES-36’s propulsion system has also changed. The ES-30’s four-engine “independent hybrid” propulsion system—comprising a pair of turboprops installed on the wing and two inboard electric motors—is gone, replaced by twin series-hybrid powertrains and a turbogenerator. Heart had been planning a series-hybrid configuration with a turbogenerator until May 2024, when it pivoted to the independent hybrid system in order to enable all-electric flight without using the turboprops.
Heart said design changes give the ES-36 a hybrid-electric range of 745 miles plus reserves, up from the ES-30’s 500 miles. It will retain the previous flagship’s 125-mile all-electric range.
JSX has converted its 2023 letter of intent for the ES-30 to a deposit-backed agreement for 50 ES-36 aircraft, with purchase rights for 50 more. The partners said the agreement will underpin a “next-generation regional fleet” intended to expand JSX’s nonstop service at community airports.
Ben Stabler, chief technology officer of Heart, said the ES-36 is a “direct result of what Heart learned designing, building, testing and flying our X1 demonstrator aircraft” and will be “more capable in the air and more productive for operators” than the ES-30.
The X1, which used the four-engine system and was designed to be representative of the ES-30, made its first all-electric flight in August at New York’s Plattsburgh International Airport (KPBG). The company said the demonstrator was the largest aircraft of its kind, by both wingspan and takeoff weight, to achieve first flight. It was originally planned to fly in 2025.
Heart’s website in August indicated a revised Part 25 certification target for the ES-30 of 2031, a slide from 2028. The company said Wednesday that the ES-36 will maintain that certification timeframe. It said the first preproduction aircraft is being built in Los Angeles and targeting first flight in the second half of 2028.
Introducing the ES-36
Each of the ES-36’s series-hybrid powertrains will drive a propeller using a 1.65-megawatt electric motor that provides instant thrust, controlled using a two-lever throttle. The same propellers will be used for electric and hybrid flight modes.
Another major change is a more “aerodynamically optimized” airframe that dedicates about 3 percent more of its maximum takeoff weight to passengers and payload. Compared to the previous flagship, the ES-36 adds 1,415 pounds of payload for a maximum of 8,492 pounds. But it retains the ES-30’s battery capacity and MTOW, which should make the new design more attractive to regional carriers.
Operators seeking to eliminate fuel burn could charge the aircraft’s batteries on the ground for all-electric flights up to 125 miles plus reserves. Range-extending, megawatt-class turbogenerators in each powertrain will enable longer, hybrid-electric missions by supplying power to the batteries in flight. Heart said the design could also enable conventional missions using Jet A. It will operate at about 25,000 feet.
The ES-36’s fly-by-wire flight deck is designed for two pilots (Honeywell was previously announced as the ES-30’s fly-by-wire supplier). It will use “digital assistance” to reduce pilot workload, as well as an architecture that Heart said is “designed to enable progressively greater automation” for single-pilot and even autonomous operation.
The aircraft will offer pilots real-time visibility into system performance for predictive maintenance and quicker troubleshooting. Rather than a centralized hydraulic system, it will use multiple self-contained electrohydraulic actuators that share a common design.
The ES-36’s length of about 84 feet falls between the ATR 42-600 and ATR 72-600. Its 95-foot wingspan is between those twin-engine turboprops and larger narrowbodies like the Boeing 737 MAX 8.
JSX Bets on Heart
JSX’s conversion of its LOI to a deposit-backed purchase commitment signals a newfound vote of confidence in Heart. The public charter air carrier also secured early delivery positions for an unspecified number of aircraft.
JSX also has agreements for up to 150 hybrid-electric 19-seaters from Aura Aero and up to 82 Electra EL9 Ultra Short aircraft, a nine-seat hybrid model. But as of Tuesday, its website said that among the sustainable models it is exploring, Heart’s aircraft “most closely mirror our current existing fleet.”
According to Heart and JSX, the ES-36 will help the carrier expand service at Santa Monica (KSMO), Westchester County (KHPN), Naples (KAPF), and other airports it already serves. The design’s short-field performance could also enable operations at “constrained airfields,” they said, and its curtailed wingspan—about 10 percent shorter than the ES-30’s—will enable higher utilization at busier airfields.
Lower operating costs could open up new, nonstop JSX routes with lower fares for passengers. And the aircraft’s all-electric mode could assuage local communities’ concerns about aircraft noise, such as in Santa Monica, where the airport faces closure due to residents’ complaints.
Alex Wilcox, CEO of JSX, said the carrier is excited to “back the development” of the ES-36 and will work with Heart to tailor it for its operations. The agreement includes what the partners described as a “working partnership,” under which they will jointly enhance the ES-36’s cabin configuration and onboard experience and study charging and turnaround procedures, route planning, and airport readiness.
Heart’s next-largest customer is United Airlines, which placed an order for 100 of the manufacturer’s earlier ES-19 model that it later converted to the ES-30. Michael Leskinen, United’s chief financial officer, in August said the ES-30 would have a “potential future role in United’s network.” The carrier did not immediately convert its order to the ES-36, but it could follow in JSX’s footsteps.
Other ES-30 customers who could pivot to the ES-36 include Mesa Air Group, Air Canada, Loganair, and Scandinavian Airlines, though most of their orders are not firm.