New eVTOL and UAV platforms mark key advances in urban air mobility

Unmanned Cessna 208B Caravan (Credit: Reliable)

As we are always looking for news on electric vertical take-off and landing vehicle (eVTOL) progress, the United Kingdom has recently stepped up with Gloucestershire-based Vertical Aerospace in the Cotswolds area, a beautiful part of Southwestern England.

The company flew its new VX4 prototype from Cotsword airport to RAF Fairford (a military airport) for the Royal International Air Tattoo (RAIT), one of the world’s largest military airshows. This demonstration marked the first flight between two public airports in the country. The VX4 was also the only eVOTL on display at RAIT.

RAF Fairford, which also serves as a base for the U.S. Air Force in Europe, has hosted aircraft including the U.S. B-52, B-1, B-2 bombers and U-2 reconnaissance aircraft. This year, RAIT featured several hundred aircraft from 30 countries, with around 200,000 attendees.

The VX4 is equipped with eight tilt-and-lift propellers that provide redundancy for takeoff, landing and horizontal flight. The aircraft is designed to carry four passengers and one pilot.

The avionics include proven Honeywell flight controls, and the lightweight airframe is constructed from carbon composite materials. Vertical Aeropspace said the eVTOL is designed to meet the same UK and European certification requirements as existing conventional passenger aircraft.

The VX4 is designed with extremely low noise characteristics in both hover and horizontal flight at up to 150 mph. The company plans to use a hybrid-electric power unit in its production models.

With a range of 100 miles and a max speed of 150mph, VX4 is being touted for short hops to overcome crowded city roads, or in London, avoiding changes on the underground while toting cumbersome luggage, and flying between downtown and one of London’s busiest airports.

The VX4 can be reconfigured to carry cargo and is powered by specially designed batteries built for high output and rapid recharging, enabling quick turnaround for trans-city passenger transport.

While aiming to replace helicopters for short hops over the city, Vertical Aerospace claims the VX4 offers far quieter, less maintenance-intensive and lower operating costs. There has been no mention of autonomous operations at this stage, but with all the necessary capabilities in hand, it’s possible that pilotless, automated flight could be possible at some future stage.

Reliable Robotics (Reliable) has been around since being founded in 2017 – they have the objective of automating flight for General Aviation (GA), passenger airlines and cargo aircraft. Reliable reports that roughly 400 people are killed each year in GA through loss of flight and controlled flight into terrain accidents. Reliable believes that about 70% of issues could be prevented by their automation systems. For airlines, 1397 people died in 75 fatal accidents between 2017 and 2021.

Working with the US Air Force (UASAF), FAA and NASA, Reliable first equipped and flew an unmanned Cessna 172 and later did the same with a Cessna 208B Caravan, similar to those operated by Federal Express (FedEx). In the process, they developed their own detect and avoid (DAA) system and qualified their own actuators to FAA standards. With the intention of developing a certifiable autopilot which would manage taxi, take-off, en-route flight, and landing, Reliable implemented a multiple flight management system which is supervised by a remote pilot.

With the extensive use of simulations, around 140 landings were first accomplished and the third landing of the actual equipped aircraft was fully automated. It may have seemed a little unnerving at first to see the aircraft taxi out to the runway with no pilot in the cockpit!

Nevertheless, it was clear that the system worked extremely well, with a remote voice interface, ground control, data link control, and monitoring of the aircraft system. With over 5000 airports available around the US, only 130 actually experience commercial operations, so the scope of enabling automated cargo transport activity more extensively across the nation appears to have room for expansion.

Reliable has just begun more simulation work with NASA — automated aircraft human-in-the-loop detect and avoid (DAA); loss of the command and control (C2) link and the necessary reversionary recovery systems, and management of the automated aircraft alongside manned aircraft as they both enter and leave airports. Work is intended to figure out the level and type of automated systems required for safe integration of large volumes of cargo-carrying unmanned aircraft systems (UAS) into the National Airspace System (NAS).

Northrop Grumman had Scaled Composites (SC) build a prototype (Model 437) manned UAV, which, according to the company, is now destined to become a testbed for autonomous systems development.

Now called Beacon, the testbed originally flew in August 2024, possibly as a contender for the Loyal Wingman Collaborative Combat Aircraft opportunity, with a Pratt & Whitney 3400 lb thrust jet engine and an internal weapons bay capable of carrying 2000 lb of weapons. SC originally built the M437 as a platform to demonstrate Northrop’s digitally engineered wings.

Now, Northrop is providing the airframe to enable collaborative partners to further develop autonomy capability to be used in future Northrop programs.

Nice to see some VTOL air taxi development in the UK, an outfit focusing on the insides of UAV autonomy and even an aircraft platform for developers to use — all together interesting times for autonomous UAV growth.