[11] In 2015, NASA researchers were ground testing a 31 ft (9.4 m) span, carbon composite wing section with 18 electric motors powered by lithium iron phosphate batteries.

Preliminary testing up to 40 mph (64 km/h; 35 kn) took place in January at Oceano County Airport on California's Central Coast.

Mounted on a specially modified truck, it was tested at up to 70 mph (110 km/h; 61 kn) across a dry lakebed at Edwards Air Force Base later in 2015.

[11] The X-57 project was publicly revealed by NASA Administrator Charles Bolden on 17 June 2016 in a keynote speech to the American Institute of Aeronautics and Astronautics (AIAA) at its Aviation 2016 exposition.

[14][15][16] In July 2017, Scaled Composites was modifying a first P2006T to the X-57 Mod II configuration by replacing the piston engines with Joby Aviation electric motors, with plans to fly early in 2018.

Mod IV configuration will see the installation of the Xperimental, LLC high aspect ratio wing with 12 smaller propellers along its leading edge to augment its takeoff and landing aerodynamic lift.

The experience helped Electric Power Systems develop a battery for the Bye Aerospace Sun Flyer 2 which made its first flight in April 2018.

It was planned that contractor ES Aero would lead extensive ground-tests over months, culminating in a mission-like 30 minutes at full power test, before flying within 2019.

[19] By September 2018, the first Joby Aviation JM-X57 electric cruise motors were mounted with controllers, batteries and new cockpit displays at Scaled Composites in Mojave, with flight tests planned to begin in mid-2019.

Construction of the ESAero high aspect ratio, low drag composite wing was then almost finished, to fly the Mod 3 by mid-2020.

[6] The wings will be optimised for cruise, with the motors protecting it from low-speed stalls and achieving the small aircraft standard of 70 mph (113 km/h; 61 kn).

[7] The speed of each propeller can be controlled independently, offering the ability to change the over-wing airflow pattern to cope with flying conditions, such as wind gusts.

When cruising, the propellers closer to the fuselage could be folded back to further reduce drag, leaving those towards the wing tips to move the plane.

[7] The wing features twelve 1.89 ft (0.58 m) diameter cruise propellers that each require 14.4 kW (19.3 hp) of motor power at 63 mph (102 km/h; 55 kn) and turn at 4,548 rpm.

Each wingtip hosts two 3-blade 5 ft (1.5 m) diameter cruise propellers that each require 48.1 kW (64.5 hp) at 170 mph (280 km/h; 150 kn) and turn at 2,250 rpm.