Sora Aviation Completes Subscale S-1 eVTOL Testing

Sora Aviation has completed the initial flight test campaign of its subscale demonstrator for its planned 30-seat S-1 eVTOL concept. Over the course of several months, the UK start-up has made dozens of flights with the subscale aircraft to validate its proprietary flight control architecture.

Announcing the milestone in June, Sora Aviation senior aerodynamics engineer Luke Brown said that data collected has shown “excellent correlation” with flight dynamics models and simulation results. These include ongoing laboratory testing and wind tunnel campaigns.

Speaking to AIN, Sora clarified that the demonstrator configuration represents the full-scale aircraft’s overall geometry, control surfaces, propulsor positioning and centre of gravity.  The company also provided further details about the S-1’s high-voltage (over a kilovolt) battery-electric propulsion system, which it said is being designed and integrated in-house.

“While many current small air taxis rely on systems operating at around 800 volts and below 300 kilowatts, Sora has already designed, built and successfully tested a 1,200 volt inverter,” the company explained in a written response to questions.   

In-Wing Batteries

Wing-integrated battery packs “provide structural bending relief while also improving safety by physically separating the batteries from the passenger cabin,” the company stated. These packs—based on commercially available cells with a pack-level specific energy of 275 Wh/kg—will be designed and integrated by Sora in collaboration with the University of Bath.

This work is supported by the UK Aerospace Technology Institute-funded Batwing program, announced in early 2025, which is due to run until early 2028. In March 2025, Sora announced a "pre-order agreement" with Korean charter operator Moviation for up to 20 examples of the S-1.

According to Sora, it is on track for a targeted first flight of its full-scale, 30-seat S-1 concept in 2028. The next program milestone is to conduct full-scale proprotor testing on a dedicated whirl tower currently under construction in Bristol.

Scheduled for 2027, these tests are intended to validate the S-1's large proprotor architecture, which Sora claims will alleviate the high hub loads encountered during edgewise and transition flight. According to the company it is now building multiple additional ground and flight demonstrators to support the maturation of key technologies and systems across the program.

Sora is targeting type certification and entry into service in 2031, and, having closed a private investment round and secured funding grants, will be seeking to raise additional capital as it progresses through development milestones. The company told AIN it hopes that the 30-seat aircraft will draw investors “looking to back category-defining companies rather than incremental variations on existing [smaller] air taxi concepts.”