Vertical completes phase one of piloted testing

Vertical Aerospace’s VX4 prototype has completed the first phase of its piloted flight test programme.  

Test pilots conducted multiple tethered flights and ground runs, across 20 piloted test sorties, completing a total of 70 individual test points, according to Vertical. The tests simulated various operational situations including the aircraft’s ability to handle failures. 

As a result of the test, Vertical’s engineers have collected and will measure 35,000 flight and system parameters. Once verified, the flight envelope will be expanded to piloted thrustborne flight, said the company, which is also working with the UK regulator on expanding its permit to fly in preparation for phase two.

Stuart Simpson, CEO of Vertical Aerospace, said: “It took us just one week to go from our first ground test to our chief test pilot flying the VX4, and we have been making outstanding progress since then. We continue to prove the safety and performance of our design and technology, which we believe to be market leading.”

He added that getting to this stage of testing is a “significant feat” for any eVTOL firm, demonstrating the strength of the aircraft. 

One of the most important tests successfully carried out included simulating the failure of an electric propulsion unit (EPU) while in piloted tethered flight, to ensure the aircraft responds correctly and continues to be safe while in flight conditions.

Vertical’s engineers have also completed a series of low and high-speed taxi tests, including deliberately failing EPUs at high taxi speeds to assess controllability and safety across the taxi envelope. 

At a glance: Phase one of testing  

• Piloted tethered flight: Performed using closed loop flight control to ensure the aircraft’s stability and safety in a controlled environment. Also included simulated failure testing to validate one EPU deliberately failing and assessing automatic aircraft response to bring other engines to maximum power output while in tethered flight.
• Ground vibration testing (GVT): Working with specialists ATA Engineering, eight heavy duty shakers were installed on the VX4 while it was suspended in the air to stress test the aircraft in different situations when flying, such as turbulence. 350 accelerometers — devices that measure the aircraft’s movements and vibrations during testing — were installed on the inside and outside of the aircraft to collect the data.
• Powertrain testing: Understanding how the powertrain is operating and evaluating all the components that generate and deliver power to the propellors. This includes a High Voltage (HV) ripple test to measure and analyse voltage fluctuations (ripple) generated on the powertrain and ensuring the battery can handle it, even at low charge, while providing a stable power supply. This is carried out while the aircraft is tethered in hover.
• Dynamic testing: Ensuring all systems are functioning correctly before they are put into use in flight in real-life conditions – such as powering up, checking the parts are installed and connected correctly and the systems and components work.
• Propellor testing: Propeller balancing and spinning tests to measure weight distribution of each propeller blade to ensure vibrations are minimised for smooth, stable flying.
• Taxi testing: VX4 is piloted at low and high speeds on the ground to test the aircraft can move forwards and backwards effectively, testing brake performance and direction of control using differential thrust.