As Vertical Aerospace prepares for the landmark first flight of a full-scale, fixed-wing VA-X4 eVTOL prototype later this year, engineering work is intensifying and the UK-based company is preparing for a type certification process that should see the four-passenger aircraft enter commercial service in 2024. Initially, the eVTOL is expected to fly with launch customers including American Airlines and Virgin Atlantic Airways, and more operators are expected to follow, with leasing group Avolon also having committed to early orders.

In June, these three companies agreed to buy up to 1,000 aircraft in the eVTOL sector’s largest deal to date. American Airlines and Avolon have joined other investors, including Honeywell, Rolls-Royce, and Microsoft, in backing plans for an initial public offering through a merger with special purpose acquisition company Broadstone.

In an interview with FutureFlight, Vertical president Michael Cervenka said that his team is now focused on completing detailed design work, with the assembly of the first X4 and long-lead items such as batteries and the wing now well advanced through their manufacturing processes. The first prototype, assembled from Solvay’s composite aerostructures, will fly with Honeywell flight controls and a complete avionics suite.

Work to prepare for the first flight has included multiple ground rig tests to evaluate different rotor configurations, optimizing factors such as airframe weight, aerodynamics, noise, and bird-strike tolerances. The company recently completed tests with a subscale model in an Airbus wind tunnel.

Now the Vertical team is building a more advanced pilot-in-the-loop simulator with Microsoft as its partner in work that Cervenka said has “pushed the boundaries for 3D simulation.” It is also using a testbed for the complex evaluation of all avionics and flight control systems in different flight cycles. “This is a really good way for us to test everything,” Cervenka explained. “We can inject different fault and failure conditions and put them through different flight cycles and make sure that the integration of software and hardware is doing what we want.”

Despite the progress being made on the ground, flight tests will add an extra dimension to Vertical’s development and certification effort. The company flew two earlier technology demonstrators before settling on the design for the X4, and Cervenka said that flight testing full-scale vehicles always delivers valuable information for engineers. “It’s there to validate earlier [ground] tests and to make sure we didn’t miss anything,” he added.

No substantial changes are expected for the basic architecture of Vertical’s eVTOL vehicle, with its high, 15-meter (49-foot) wing and eight rotors. The initial X4 prototype will fly with an interim set of motors, as Rolls-Royce finalizes the development of its bespoke electric propulsion system, which will be more powerful and lighter than the first test unit. The first production examples of the propulsion units are set to be delivered in late 2022.

When Bristol-based Vertical started working on its eVTOL plans, the UK was still a member of the European Union (EU) and its aerospace industry was accountable to EASA. Following the country’s Brexit departure from the EU at the end of January 2020, the European Aviation Safety Agency no longer has direct jurisdiction over British aviation companies and so Vertical is now working with the UK Civil Aviation Authority.

However, according to Cervenka, for all the UK government’s doctrinaire protestations about not accepting EU rules, the British regulator appears to have stayed closely aligned with EASA’s approach to type certification of eVTOL aircraft. He says this regulator seems to be significantly more stringent than the FAA, with requirements to meet the same safety standards as large commercial airliners as opposed to those for smaller general aviation aircraft and helicopters.

“It’s a big burden but we are comfortable doing this because we see this as a mass-market [product] that will fly with passengers over built-up areas,” Cervenka said. “It gives us a strong foothold in Europe and, with countries like Japan leaning in the same way, it gives us a route to global markets as well as a good path to certify with the FAA as well.”

According to Cervenka, type certification is the biggest challenge facing eVTOL developers, and he expects only a handful of the many contenders to make it to this stage. “This is why we have taken a partnership approach to leverage world-class tier-one aerospace companies, like Honeywell, GKN, and Solvay, with decades of experience certifying safety-critical equipment so that the process is a shared burden,” he said. “We don’t have to be best-in-class with everything we do, as we’re leveraging pipelines from partners to access world-class technology that is available externally.”

Vertical believes that the competitive edge with its eVTOL will come in areas such as the battery system, including packaging and power management, as well as its rotors. It is anticipating a battery recharge time of just 10 minutes.

The vectored thrust propulsion will use all four front rotors throughout the flight envelope, with the V-shaped tail minimizing weight and drag. “There is no duplicated powertrain [between lift and cruise flight] and we can maximize the disk or rotor area for efficient hover,” explained Cervenka.

The Vertical eVTOL, which still hasn't been given a brand name, features a cabin with a separate area for the pilot at the front. The main cabin area features a club-four seating layout for the passengers.

According to Cervenka, airport-to-downtown connections will be among the early-use cases for eVTOLs. Connections such as Manhattan to New York’s John F. Kennedy International Airport—a likely first route for American Airlines—are obvious candidates, along with Heathrow Airport to the center of London. However, given the Vertical eVTOL’s projected range of around 100 miles, Cervenka also sees potential for UK cities like Cambridge and Oxford to enjoy vastly improved connections to this major hub.

Like other eVTOL pioneers, Vertical says that its electric aircraft will be highly disruptive in the air transport sector, with claimed safety improvements and noise reductions of up to around 100-fold compared with existing helicopters. Vertical says its vehicle will deliver operating costs of around one-fifth those of today’s rotorcraft, equating to a per-passenger-mile cost of just $1. It projects typical airport shuttle costs to be as low as around $30 to $40 per person, depending on the location.

“American [Airlines] sees this as a way to seamlessly integrate services with their existing hub-and-spoke airport model, and they carry around 200 million passengers each year so it’s a massive opportunity,” Cervenka said.

UK-based Virgin Atlantic is eyeing a different business model that would involve launching ultra-short-haul domestic airline services. For Vertical, this is set to entail a partnership to connect regions with flights between cities like Liverpool and Leeds, Bristol to Brighton and Cardiff, and Leeds to Hull, offering a way to overcome geographic constraints such as inadequate highways and slow train connections.

According to Cervenka, there is greater potential for inter-regional services across the rest of Europe where he said there are around 230 to 240 cities with populations of at least 300,000 with many pairs of cities that are only about 100 miles apart. By comparison, Vertical says there are just 60 such cities in the U.S., and it also sees growth prospects in Asia and South America.

Initially, Vertical expects existing heliports, fitted with electric charging facilities, to be the main points for eVTOL arrivals and departures. The company believes that the significantly reduced noise and projected higher degrees of safety will open up multiple sites that are currently limited to emergency services.

Avolon has a customer base of some 150 airlines worldwide, and Vertical believes that eVTOLs could soon start featuring in leasing portfolios, which now account for 40 to 50 percent of commercial airliners bought each year. “This is not just a great route to link up with airlines, but also with the wider aerospace industry and possible partners among companies like MRO [maintenance, repair, and overhaul] providers,” Cervenka said.

In his view, the sort of intra-city urban air mobility services targeted by many eVTOL developers will take longer than expected to flourish, in part because of the need to win public acceptance. He doesn’t see this activity dominating the market until around the mid-2030s.

While Vertical is certainly eager to sell its aircraft in the private aviation sector, where high-net-worth individuals are currently transported in business jets and helicopters, its main ambition is the mass market. “We don’t want to just develop something for the uber-rich,” Cervenka concluded. “The objective is something where most people in most cities can really benefit and when we reach that tipping point it will be easier to get public acceptance for these aircraft flying over people’s heads.”

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