Electra EL-2 Goldfinch

The Electra EL-2 Goldfinch is a technology demonstrator developed by U.S. startup Electra.aero. The EL-2 is a hybrid electric aircraft with distributed propulsion for short takeoff and landing (STOL).

Development
Electra creator John Langford founded Aurora Flight Sciences in 1989, sold to Boeing in 2017.

The first test flight happened on November 11, 2023, all-electric powered, from Manassas Regional Airport in Virginia. On November 17, it flew again for 23 minutes, powered by its hybrid-electric drivetrain, reaching 3,200 ft. Electra wants to develop a nine passenger-aircraft (or 2,500 lb of cargo) capable of operating from an area soccer field-sized with a 150 ft ground roll, for a 500 mi range. The company aims to fly a full-scale prototype in 2026, then a certification test aircraft targeted for a 2028 introduction.

By late April 2024, the demonstrator had flown for over 10 hours and had achieved 150 ft landings and 175 ft takeoffs. Its longest flight exceeded 1.5 hrs, its highest altitude reached was 6,500 ft, and its lowest speed achieved is 25 kn. Electra envisions a 200-seat turboelectric airliner for 2040, for which it has submitted a proposal for the NASA Advanced Aircraft Concepts for Environmental Sustainability.

Electra uses a hybrid powertrain as lithium-ion batteries pack not enough energy, only 170 Wh/kg in the Pipistrel Velis Electro in 2020, approaching 235 Wh/kg at the pack level for 2025. The Advanced Research Projects Agency-Energy (ARPA-E) has launched the Propel-1K program to demonstrate a 1,000 Wh/kg cell by mid-2025.

Design
The Goldfinch has a turbogenerator in the nose for hybrid propulsion and battery packs under the floor for all-electric operation. It has a two-person cockpit and a gross weight of 3,100 lb. To take off at 30-35 kn, it has a blown-lift wing, generating a pitching moment balanced by a large T-tail. It has a modified Cessna 172 wing, and its 150 kW powertrain employs a helicopter auxiliary power unit while its battery packs handle peak power.