Vertical Aerospace’s VX4 prototype achieves major milestone with launch of Phase 2 piloted flight testing
Vertical Aerospace’s full-scale VX4 prototype has completed piloted, untethered vertical take-off and landing for the first time, as Phase 2 of its flight test programme begins.
The VX4 prototype, which delivers up to 1.4 MW of peak power, surpassed expectations in hover performance, control and stability. Testing will now progress to low- speed manoeuvres using lift generated by the propellers at its Flight Test Centre at Cotswolds Airport in Gloucestershire, UK.
Stuart Simpson, CEO of Vertical Aerospace, said: “It’s great to see the VX4 throw off the tethers and move to the next phase of our piloted test flight programme. We now enter a realm that very few companies in the world have achieved.
“Our team is thrilled with the significant strides we continue to make with the VX4 prototype as we expand our learnings and take another step towards connecting communities with faster, cleaner and safer travel.”
Thrustborne flights are designed to assess the aircraft’s stability, battery efficiency, control characteristics, aerodynamics, structural and dynamic loads and performance across different speeds, enabling further assessment of how the VX4 behaves under real-world flight conditions.
This marks an expansion of the VX4’s flight envelope beyond the initial tethered hover condition in Phase 1, as the prototype continues to operate under more demanding conditions, ensuring it meets the most stringent safety and regulatory standards.
The second of four testing phases follows the UK Civil Aviation Authority’s (CAA) expansion of Vertical’s Permit to Fly. To secure this expansion, Vertical submitted extensive documentation verifying the VX4 prototype’s safety under Phase 2 conditions.
This included systems and structural validations, Phase 1 outcomes, flight test protocols, engineering specifications, and detailed operational procedures.
Simon Davies, Vertical’s Chief Test Pilot, who flew the VX4 prototype, added: “The aircraft performed absolutely brilliantly, and was really stable in the hover. The flight controls felt good, and it’s great to have the tethers off. Everything on the aircraft worked perfectly — no surprises, nice and boring — a great test flight.
“Definitely my favourite and most memorable flight in thousands of flight hours, but my job was really easy — standing on the shoulders of giants! So proud of our team.”
Vertical will now progress through Phase 2 while working with the CAA to extend it’s Permit to Fly and move onto Phase 3 — wingborne flight tests. This next stage will involve piloted take-off, flight, and landing like a conventional aircraft using wing-generated lift.
The primary focus of this phase is expanding the transition envelope as safely as possible — working down in speed from high altitude rather than up in speed from low altitude, which is much safer. Phase 4 will involve transitioning between thrustborne and wingborne flight modes.
Vertical is currently developing an identical full-scale prototype which will accelerate the VX4’s flight test programme and demonstration capability. Once assembled, the company will take flight test learnings from both prototypes into the design and development of the certified VX4 model.
Piloted flight test programme explainer
- Phase 1: Tethered: the VX4 will perform stabilised hover while loosely tethered to the ground. COMPLETE
- Phase 2: Thrustborne: the VX4 will take-off and land vertically and conduct low speed flight manoeuvres
with lift generated by the propellers. STARTED - Phase 3: Wingborne: the VX4 will take-off, fly and land like a conventional aircraft, with lift generated by
the wing - Phase 4: Transition: The VX4 will transition between thrustborne and wingborne flight, and vice versa
