LE BOURGET—Chinese startup AutoFlight is debuting its fourth full-scale proof-of-concept electric-vertical-takeoff-and-landing air taxi at the Paris Air Show show here.

It is the last before the company builds conforming prototypes for certification of its aircraft with the Civil Aviation Administration of China (CAAC).

The aircraft on display is a further refinement of AutoFlight’s lift-plus-cruise electric-vertical-takeoff-and-landing (eVTOL) configuration. It has 10 lift rotors on wing booms for vertical flight and three pusher propellers for cruise flight. The aircraft is fitted with an interior for a pilot and four passengers conceived by car designer Frank Stephenson.

The proof-of-concept aircraft here has yet to fly, but the previous three have completed thousands of transitions between rotor-borne vertical and wing-borne horizontal flight in uncrewed testing in China, AutoFlight CEO Tian Yu says.

The next step is type certification of the uncrewed cargo version of the 2,000-kg (4,400-lb.) gross-weight aircraft, the Carryall, with the CAAC. This is expected in 2024, says Mark Henning, AutoFlight's managing director.

The CAAC recently published the certification basis for the Carryall, which Henning says resembles a combination of the European Union Aviation Safety Agency’s (EASA) Special Condition for VTOL (SC-VTOL) and FAA regulations for the electric propulsion system.

The carryall is designed to lift a 400-kg payload 200 km (125 mi.). Henning says certification will allow AutoFlight to begin delivering aircraft to customers in China and Asia and start gathering operational data for the next step: certification of the passenger-carrying Prosperity 1 version with the CAAC.

The aircraft are essentially identical, and Chinese certification of the Prosperity 1 is expected 2 1/2-3 years after that of the Carryall, Yu says. Where the Carryall uses NMC811 high-silicon lithium-ion battery cells with an energy density of 330 Wh/kg, the Prosperity 1 will use 400 Wh/kg solid-state batteries.

Yu says the high-silicon batteries in the Carryall cannot pass the thermal runaway tests required for commercial passenger certification, but the solid-state batteries “do not burn.” AutoFlight builds its own battery packs and a competition is underway to select the cell supplier.

The Carryall is to be certified to a safety level of 10^-5 ,while the passenger-carrying Prosperity 1 is planned to be certified initially by the CAAC at 10^-7, the same safety level as current commercial helicopters, Henning says.

After gaining operational experience in China and Asia with the Prosperity 1, AutoFlight plans to certify the aircraft with EASA. This will require a safety level of 10^-9 under SC-VTOL and is expected to take another one-two years, he says. FAA certification would follow later.

AutoFlight is vertically integrated and has developed the composite airframe, electric motors, battery packs, flight controllers and cockpit avionics in-house. The company is building a factory with the capacity to produce 1,000 aircraft a year, Yu says.

For redundancy, the 10 3-m-dia. (9.8 ft.) lift props each have dual 60-kW, 1,000-rpm motors while the three pusher props have dual 80-kW, 2,000-rpm motors. All the motors, which have integrated inverters and cooling, share common components to reduce costs, Yu says.

AutoFlight holds orders for 670 eVTOL aircraft, Yu says, from customers in China and countries in Asia that recognize Chinese certification. In addition to a low unit cost, the company is projecting direct operating cost one-fourth those of helicopters, says Henning, who was formerly with Airbus Helicopters.