Vertical Aerospace poised to begin tests with full-scale prototype

By Paul Brinkmann|August 11, 2022

Company president underscores value of piloted flights

Vertical Aerospace, the U.K-based company developing a small electric rotorcraft for local transit, plans to begin piloted test flights in a matter of weeks with a full-scale prototype, starting with a tethered hop.

This aircraft will be the final iteration before a production model of the eight-rotor aircraft, the VX4, is built in 2024 to complete certification with the European Union Aviation Safety Agency. The company, headquartered in Bristol, announced the next round of test flights in an Aug. 8 letter to shareholders.

“Clearly the goal for most of us is to test a piloted full-size vehicle,” company president Michael Cervenka told me during a video interview. “If you start with a subscale prototype, the technology doesn’t necessarily scale easily, the power equation and the battery weight may not scale. We felt doing a full-scale prototype is really critical to learning and derisking before we go into the certification program.”

Some of Vertical’s competitors in the advanced air mobility field, such as California-based Wisk Aero, have chosen to test smaller prototypes at first. Wisk plans to reveal its first full-size production model in October.

Wisk and Joby Aviation, two leading U.S. companies planning such electric aircraft, have only flown unpiloted test flights. Vertical wants to test with a pilot aboard to gain insight into how future passengers would experience such flights, Cervenka said.

“As Justin Paines, our chief test pilot, would say: ‘At the end of the day, we’re an aircraft company, we’re not a drone company,’” Cervenka said. “And so we all need to get used to setting safety standards that are commensurate with putting someone we care about deeply in the aircraft. If we can’t put our own chief test pilot in, well, how are we going to be comfortable in commercializing this and having the general public fly?”

The VX4 will be a lift-plus-thrust electric craft, meaning four rotors arrayed along the trailing edge of the 15-meter-wide main wing provide only lift, while four rotors in the front tilt for forward flight. The interior will have two chambers — a pilot cockpit area and a seating area for four passengers. A wall will separate the pilot from passengers, but there will be a window and radio communication between the two areas, Cervenka said.

“The handling characteristics that you want from a vehicle with a pilot in the aircraft are quite different that if you’re playing with something remotely,” Cervenka said. “A pilot will have a much more rapid response, knee-jerk almost, than if you are watching the aircraft perform remotely.”

In the meantime, Vertical continues to work on its rotorcraft engines with partner Rolls-Royce, battery development with partner Molicel of Taiwan and on propeller development, Cervenka said.

“You can’t pick up a textbook that says ‘this is how you design these aircraft,’” he said. “We will upgrade the propellers from what you see today, and the next model will have significant improvements in noise and aerodynamic efficiency.”

Vertical is also working with American Airlines and Virgin Atlantic, which have signed letters of intent to buy aircraft from the company, and with Heathrow Airport in London to study how AAM operators can integrate with the airport environment.

“Yes, these will fly in and out of the main airports because they can obviously land and take off vertically and they fly at lower altitudes, so you will be able to connect with an air taxi after you land at the airport and make the final leg of your journey to your hometown or destination,” Cervenka said.

He noted that Vertical’s director of infrastructure, Andrew Macmillan, is a former strategy officer at Heathrow.

“Obviously, he knows an awful lot about how you could operate these vehicles within somewhere like Heathrow,” Cervenka said.

To make such rapid connections and to provide regular service, Vertical plans for each aircraft to be capable of a full recharge after a flight of about 40 or 48 kilometers in a matter of minutes, he said.

He said the company has determined that regulations will allow immediate plug in and recharging, even as passengers board or disembark.

“You can’t be waiting on the ground for long between each flight because your aircraft utilization plummets and then your cost per passenger mile goes up,” he said. “So we’re finding we can do a really quick turnaround time, 10 or 12 minutes, and we’re back up in the air.”