UK start-up Sora Aviation is preparing to launch a Series A funding round to support its work on a planned 30-seat eVTOL aircraft primarily intended for airport shuttle services. The company is convinced that a battery-electric propulsion system integrated with six tilting rotors installed across a tandem wing configuration will be able to deliver higher payload for trips of up to around 25 miles.
Having completed their conceptual design for the S-1 aircraft, Sora’s CEO Furqan and CTO Malcolm Foster are now working on the preliminary design for what they characterize as a bus rather than an air taxi. They aim to have a full-scale technology demonstrator ready to start flight testing in 2028 as they target type certification and entry into service in 2031.
Sora’s co-founders met when they were with GKN Aerospace, where Furqan was the technical authority on the group’s advanced air mobility project team and Foster was involved in GKN’s contribution to Eviation’s Alice electric fixed-wing aircraft. Foster has extensive previous engineering experience with companies including Piper, Bell, and Leonardo.
In 2021, GKN and 15 partners launched a study into three prospective eVTOL designs with funding from the UK government’s Future Flight Challenge program. One of the concepts considered was a large eVTOL called the Skybus intended to carry between 30 and 50 passengers. Based on studies by consultants Swanson Aviation Consultancy, Pascall and Watson, and Connected Places Catapult, it was envisaged that this might be used to operate shuttle services between city center vertiports and “park and ride” facilities in more suburban locations.
Tandem Wing, Tilting Rotors
Early drawings of the S1 model show a shorter forward wing with a rotor installed at each wing tip. The longer rear wing has four rotors, with two installed inboard and two on the wing tips.
According to Furqan, their engineering studies have established that the battery weight per passenger does not need to increase for an electric aircraft with more seats since the energy consumption is proportional to takeoff weight. On this basis, Sora believes it can deliver a seven-fold increase in passenger capacity with similar battery weight per person as other eVTOL aircraft.
The company expects to partner with specialist suppliers for key elements such as electric motors and fuselage sections while using its own designs for systems such as the tilting rotors. In the longer-term, it may subsequently consider alternative powertrains such as hydrogen-electric and diesel-based hybrids for possible military applications.
Furqan pointed to a recent study by consultancy Roland Berger suggesting that the majority of early eVTOL use cases could be short-hop trips between airports and city centers. Sora envisages its S1 requiring H2-grade 24-meter (79-foot) helipads that could be part of city center vertiports that also offer H1-grade pads for smaller eVTOL vehicles. The company also expects its aircraft to find applications such as short island-hopping flights.
Sora forecasts that prices for airport shuttle trips of around 25 miles will amount to between $30 to $40 per passenger. By extrapolating data from the Roland Berger report on unit economics for advanced air mobility, it said estimates for the same trip in a typical eVTOL air taxi would be priced at $7.70 per passenger-mile, which is higher than the earlier Uber Elevate estimates of $5.73 per passenger-mile. On this basis, Sora has projected that the cost of an eVTOL air taxi for the same 25-mile trip would be between $140 and $190 per passenger.
The company's S-1 will require H2-grade 24-meter (79-foot) helipads that could be part of city center vertiports that also offer H1-grade pads for smaller eVTOL vehicles. Additionally, it expects its aircraft to find applications such as short island-hopping flights.
Another European start-up called Lyte Aviation is already working on plans for a hybrid-electric commuter eVTOL aircraft called the LA-44 SkyBus. It said this 40-passenger aircraft could operate on routes of up to around 625 miles, and could also be offered as a 19-seat executive version and as a freighter.