Electra has finished a fully integrated test of the proprietary hybrid-electric propulsion system for its electric short takeoff and landing (eSTOL) aircraft, the Virginia-based company reported Wednesday. Electra continues to work on integrating the hybrid system into its piloted technology demonstrator, which is expected to test Electra’s eSTOL short takeoff and landing performance and fuel burn savings. The company first developed the technology for its nine-passenger eSTOL aircraft and plans to scale it for use in larger aircraft.

Backed by a significant undisclosed investment from Lockheed Martin Ventures that was announced in January, Electra subsequently accelerated ground testing of the 150-kW hybrid-electric propulsion system for a subscale, two-seat eSTOL technology demonstrator that it plans to start flight testing before the end of the year. Designed to carry nine passengers or 1,800 pounds (820 kg) of freight on flights ranging up to 500 miles (800 km), the blown-lift eSTOL aircraft has drawn sales commitments from helicopter operations group Bristow and charter flight booking platforms Yugo, Flapper, and Flyv. 

Electra calls hybrid-electric propulsion its first step on a path to zero-emissions air mobility and the only sustainable technology that can meet range requirements for the regional air mobility market. The company designed its eSTOL aircraft to adopt hydrogen and battery-electric propulsion systems when those technologies become commercially viable. To support those long-range goals, Electra has partnered with hydrogen fuel cell developer Plug Power.

“Tightly coupling airframe and propulsion systems is the hallmark of Electra’s unique and scalable approach to providing net-zero emissions for regional and transport-category aircraft by 2050,” noted Electra vice president and general manager JP Stewart. “Electra’s eSTOL aircraft uses this patent-pending technology for the urban and regional aircraft market, allowing a reduction of the five billion tons of CO₂ created by inefficient ground transport in personal cars every year.”   

Testing of the hybrid-electric system took place at Electra's propulsion development facility in Switzerland. Electra's hybrid system uses a combination of high-power battery packs and a turbogenerator to power eight electric motors and propellers.