- What it is: a piloted, four‑passenger electric vertical‑takeoff‑and‑landing (eVTOL) tiltrotor built by UK‑based Vertical Aerospace. It uses eight electric propellers—four tilting for cruise plus four lift‑only behind the wing—for redundancy and low‑noise ops. eVTOL News
- Baseline performance: targeted cruise ~150 mph (241 km/h) and range ~100 miles (161 km) for short regional hops. Vertical Aerospace
- 2025 flight‑test milestones: first piloted “wingborne” flight in open UK airspace on May 27, 2025; first public airport‑to‑airport hop (Cotswold → RAF Fairford) on July 16, 2025; Phase 3 (wingborne) testing completed Sept 5, 2025, with transition flights targeted before year‑end. Vertical Aerospace, International News
- Certification target & spend: Vertical is reaffirming a 2028 certification goal, estimating ~$700M additional funding required to get there. Vertical Aerospace
- Manufacturing set‑up: initial final assembly at an expanded Cotswold Airport site (25+ aircraft/year capacity) and battery production at an expanded Avonmouth facility near Bristol. Vertical Aerospace
- Supply chain & avionics: Honeywell is under a long‑term deal to certify the Anthem flight deck and compact fly‑by‑wire controls on VX4; Aciturri will supply the entire airframe for pre‑production and certified aircraft. Reuters
- Orderbook: ~1,500 conditional pre‑orders (e.g., American Airlines, JAL, GOL, Bristow). Vertical Aerospace
- 2023 crash finding: UK AAIB concluded the prototype’s propeller blade adhesive bond failed, causing a blade release and damage; Vertical redesigned the propellor and changed suppliers. GOV.UK
- Battery tech today: current packs deliver ~220 Wh/kg; Vertical aims to monetize battery maintenance and replacement services post‑entry‑into‑service. Aviation Week
The VX4 in one sentence
Vertical’s VX4 is the UK’s flagship eVTOL program: an eight‑prop, tiltrotor air taxi pursuing airline‑level certification in 2028 after notching a string of piloted flight milestones in 2025—and now racing to secure the $700 million it says it needs to finish the job. Vertical Aerospace
What exactly is the VX4?
The VX4 is a piloted eVTOL designed to carry four passengers plus a pilot. Unlike multicopter “drone taxis,” the VX4 has a wing for efficient cruise and a distributed electric propulsion layout: four tilting front propellers for vertical lift and forward thrust, and four lift‑only props behind the wing that scissor/stow in forward flight to cut drag. This architecture delivers redundancy (eight motors) and a quieter noise footprint—core requirements for urban operations. Target cruise is ~150 mph with ~100‑mile range, slotting it for airport shuttles and short regional hops. Vertical Aerospace
2023 accident, 2024 reset
On Aug. 9, 2023, the first VX4 prototype—remotely piloted—was damaged during flight testing at Cotswold Airport. The UK Air Accidents Investigation Branch (AAIB) later found the root cause: adhesive bond failure between a propeller blade sheath and spar, which led to blade release, structural damage, and loss of vertical thrust. Vertical says the propeller had already been redesigned and the supplier changed; it also identified 36 product/process improvements from its internal review. GOV.UK
Expert lens: Aviation Week’s Graham Warwick highlighted the accident’s lessons—eVTOL prototypes face unique hazards, and design margins must account for off‑nominal loads during early testing. That sober context explains why regulators, investors, and developers are laser‑focused on hardware and process maturity before public service. Aviation Week
2025: the year VX4 went truly piloted in open airspace
Vertical spent 2024 rolling out an upgraded full‑scale prototype with ~20% better power‑to‑weight, then entered a four‑phase piloted test program in 2025:
- Phase 2 (Thrustborne) – Jan 2025: piloted vertical takeoffs/landings and low‑speed maneuvers using lift from the propellers. Vertical Aerospace
- Phase 3 (Wingborne) – May–Sept 2025: the VX4 took off, flew, and landed like a conventional airplane, validating handling qualities in open airspace. On May 27, 2025, Vertical flew the first piloted wingborne flight of a winged eVTOL in European open airspace (under an expanded CAA Permit to Fly). On July 16, the prototype flew airport‑to‑airport (Cotswold → RAF Fairford) ahead of RIAT. Phase 3 completed Sept 5. Vertical Aerospace
- Phase 4 (Transition) – Planned 2H 2025: the make‑or‑break maneuver from vertical lift to wingborne flight (and back). Vertical says it remains on track to transition before year‑end 2025. Aviation International News also reports the team is “close” to a full transition. Vertical Aerospace
Why this matters: Transition is the defining capability for a tiltrotor eVTOL. Completing it de‑risks handling qualities, power margins, and control laws—the gate to for‑credit certification testing. Vertical Aerospace
Technology stack: flight controls, batteries, and noise
- Flight deck & fly‑by‑wire: Vertical signed a long‑term agreement with Honeywell to certify the Anthem integrated flight deck and compact fly‑by‑wire system on the production VX4 through the UK CAA (coordinated with EASA). Honeywell’s AAM lead Dave Shilliday told Reuters the deal also secures hardware production capacity as the program scales. Reuters
- Batteries: Vertical sources high‑power cells from Molicel but owns IP for pack design, thermal management, and BMS. Its current‑gen packs deliver ~220 Wh/kg, and the company is planning a battery‑maintenance business model given the pack’s share of lifetime MRO costs. Aviation Week
- Acoustics: VX4’s airframe/propeller updates and so‑called Low Noise Signature focus are designed to make it “virtually imperceptible” in urban environments—vital for community acceptance. (Independent, for‑credit noise tests will ultimately validate these claims.) Vertical Aerospace
Industrialization: where and who will build VX4?
Vertical says it has locked in its first manufacturing sites: final assembly at Cotswold Airport (next to the flight‑test center) and battery production at Avonmouth near Bristol—moves meant to reduce integration risk and support early production. In August 2025, Aciturri was selected to supply the entire airframe (wing, fuselage, pylons, empennage) for pre‑production and certified aircraft, including engineering responsibility for several structures. Vertical Aerospace
Expert lens: Aviation Week’s Graham Warwick notes Vertical is “firm” that $700M more is enough to reach VX4 certification in 2028—more than it has raised since 2016, but less than the tally many peers have budgeted. That framing underscores how much hinges on disciplined scope and supplier execution. Aviation Week
Commercial plan and partners
Vertical continues to cite ~1,500 conditional pre‑orders, including marquee names like American Airlines (deposit‑backed slots for the first 50 aircraft), Japan Airlines, GOL, and Bristow. In June 2025, Bristow expanded its partnership with Vertical, committing to up to 50 VX4s plus 50 options and launching a “ready‑to‑fly” model that leans on Bristow’s pilots, maintenance, and insurance—an approach meant to lower barriers for early operators. Vertical Aerospace
Reuters also reported a deepened Honeywell collaboration in May 2025 (potentially up to $1B over a decade) to certify the VX4’s avionics and flight controls under CAA/EASA oversight—an anchor systems partnership that removes critical program risk. Reuters
A new twist: a hybrid‑electric VX4 variant
In May 2025, Vertical unveiled plans for a long‑range hybrid‑electric version aimed at defense, logistics, and other missions requiring higher payload/range—up to ~1,000 miles and 1,100 kg payload, with flight testing targeted for Q2 2026. The company says a VX4 prototype will be retrofitted with the hybrid system. (As always, these are development targets pending demonstrations.) Reuters
Expert lens: Aviation Week’s Warwick wrote that market interest in a hybrid variant is strong, particularly where endurance and off‑grid ops trump zero‑emissions purity—an acknowledgment that pure‑electric ranges may limit early mission sets. Aviation Week
Regulation and timelines
While VX4 is pursuing certification with the UK CAA with EASA coordination, every regulator is feeling its way through first‑of‑type powered‑lift aircraft. As Mike Hirschberg of the Vertical Flight Society has argued, evolving certification frameworks (e.g., FAA’s 2022 “powered‑lift” pivot) underline why schedule realism is as important as technology. Vertical’s public target is 2028, with initial deliveries around 2030—aggressive, but within the band many analysts see for non‑U.S. type certifications. vtol.org
Funding, risk, and reality checks
- Funding runway: CEO Stuart Simpson told Reuters in May 2025 that cash on hand would last through end‑2025, with additional fundraising planned to support operations into 2026 and beyond. The company’s Capital Markets Day reiterated the $700M requirement through certification. Reuters
- Supplier changes: After Rolls‑Royce exited electric propulsion, Vertical and RR mutually ended their electric‑propulsion agreement in May 2024; Vertical has since moved to alternative suppliers. Supplier solidity is a watch‑item in 2026–2028. Vertical Aerospace
- Technical milestones ahead: the transition flight (planned for late 2025), for‑credit certification tests, and mature battery performance in hot/cold/extreme duty cycles remain key proof points. Aviation International News reported this month that Vertical is close to full transition, but flight‑test programs can surprise on schedule. Aviation International News
Why 2025 mattered for VX4
2025 turned VX4 from a test site curiosity into an aircraft flying piloted in open airspace, even airport‑to‑airport before a global audience at RIAT. As Honeywell’s Dave Shilliday put it, the latest deal is about ensuring there’s enough certified hardware for Vertical’s planned build and customer demand—an “industrial” signal beyond flight tests. The remaining question is as much finance as physics: can Vertical close the $700M gap to carry VX4 from impressive prototypes to certified, revenue‑earning aircraft by 2028? Reuters
Sources & expert references
- Flight testing & milestones: Vertical press releases (Jan 8, May 27, July 17, Sept 9, 2025); Aviation International News reporting (May 27, Sept 9, 2025). Aviation International News
- Accident & safety: UK AAIB report and summaries; Vertical statement (May 2, 2024); FlightGlobal/VerticalMag coverage. Vertical Mag
- Specs & architecture: Vertical site and VFS eVTOL.news database; Ansys technical article on propeller configuration. Vertical Aerospace
- Certification & partners: Reuters (Honeywell systems deal; Bristow partnership); Honeywell press; Aviation Week reporting on funding and hybrid interest. Aviation Week
- Manufacturing & spend plan: Vertical Capital Markets Day release (Sept 17, 2025); Aciturri partnership announcement. Vertical Aerospace
- Battery tech & MRO outlook: Aviation Week (Sept 25, 2025). Aviation Week
Bottom line
The VX4 is no longer theoretical—it’s a piloted aircraft flying in everyday British airspace, with credible Tier‑1 partners and a maturing industrial plan. The hardest miles remain (transition, certification, and capital), but after 2025’s progress, the question isn’t whether VX4 can fly—it’s whether Vertical can fund and certify it quickly enough to be among the first eVTOLs carrying paying passengers by the decade’s end.
