Roads are dangerous and increasingly congested places. Every year around 1.35 million people die in motor accidents worldwide according to the World Health Organization, with between 20 and 50 million non-fatal injuries on top.
Congestion is worsening in major urban centres. In cities like Los Angeles commuters spend an estimated seven working weeks each year driving to work, two of which are wasted in traffic congestion. And the situation will only worsen, as it’s thought that 60 per cent of all people will be living in cities by 2030.
Clearly something needs to be done. Self-driving ride-share services could ease the problem and help cut down the number of road accidents, 94 per cent of which are caused by human error. But for a complete solution to the problem of traffic, more and more people are looking to the skies in the form of personal air vehicles (PAVs).
Electric vertical take-off and landing vehicles (eVTOLs) can make urban travel up to five times faster, at the same relieving traffic congestion, road accidents and noise and environmental pollution. And some versions are taking humans out of the equation altogether by pioneering self-piloting systems.
Here are ten of the most promising developments.
Airbus’s eVTOL, CityAirbus (pictured above), first took to the skies in May 2019 in a demonstration flight. Since then it has clocked up more than 100 test flights in its sub-scale format.
The design is certainly unique, perhaps even iconic, with four huge 2.8-metre ducted high-lift propulsion units that give it something of the look of a massively oversized fidget spinner. The eight propellers are powered by eight 100kW electric motors at around 950rpm to minimise noise pollution, providing a top cruise speed of 75mph.
CityAirbus is designed to be single-engine-failure tolerant. It will carry four passengers and be piloted remotely, providing 15 minutes of autonomy. This will be integrated into Airbus’s Unmanned Traffic Management system – a work-in-progress project to provide digital air traffic management for all the unmanned PAVs and drones that will soon be proliferating in city skyscapes.
The company’s Urban Mobility initiative will also look at how to incorporate critical infrastructure into cities, like vertipads for vertical take-off and landing in sustainable, compact and efficient ways.
Hyundai’s S-A1 concept was launched in January as part of Uber’s Elevate programme to develop fleets of eVTOL ‘air taxi’ vehicles for ride-sharing at scale.
The personal air vehicle (PAV) uses distributed electric propulsion – lots of small rotors to increase lift, reduce noise and enhance safety by limiting the impact of any single point of failure. Four of the rotors are designed to pivot, transitioning the aircraft from vertical take-off to forward, wing-borne flight, while four more provide extra lift during take-off and landing.
The S-A1 is designed to carry four passengers plus personal baggage in the back with a pilot up front. However, Hyundai envisages the technology going autonomous in the near future. It is fully electric-powered and can cruise up to 180mph with a range of up to 60 miles. Recharging takes just five to seven minutes.
The partnership will see Hyundai produce and deploy the vehicles while Uber provides airspace support services, connections to ground transportation, and customer interfaces through an aerial ride-share network.
Both companies are collaborating on infrastructure concepts for take-off and landing sites.
Caltech: Flying ambulance
In some urban environments traffic jams can kill, literally. In cities like Sao Paulo, Brazil, traffic congestion is so bad that helicopter ambulances are common and helicopter ride-sharing schemes are already popular alternatives to sitting it out on the ground.
However helicopters are too large, costly, noisy, and accident-prone to operate well in a dense urban environment. The answer could be unmanned eVTOL air ambulances, which is exactly what a team from Caltech is working on. Principal investigators Soon-Jo Chung and Mory Gharib are developing a craft with three banks of rotors along each side of the fuselage mounted underneath a set of fixed wings so that it can seamlessly transition from vertical take-off to forward flight.
The other side of the research project is the autonomous flight system, which must be able to navigate restricted urban areas full of other flying vehicles, objects and buildings, as well as being stable and secure enough to transport injured patients to hospitals. Despite the challenges, the team believes it should be easier than achieving full autonomy for self-driving cars because of the reduced complexity of the vertical airspace (no pedestrians, drivers, and other human factors).
Other applications could extend to ride-sharing air taxis and even next-generation eVTOLs used to explore Mars.
Porsche and Boeing: eVTOL concept
Looking like something out of a Batman movie, Porsche and Boeing’s shared concept for an eVTOL certainly makes up in style what it lacks in substance.
Image credit: Porsche | Boeing
Announced in October last year, the collaboration between Boeing, Porsche and Aurora Flight Sciences is still very much at the concept stage, with no prototype or even a name for the vehicle.
The companies have said they will work hard to develop a luxury electric flying car that can fly short hops across cities. It seems that the product will be targeted at the high-end market using Porsche’s design expertise, while Boeing focuses on the logistics of providing a next-generation ecosystem for urban autonomous and piloted PAVs.
Some clues as to progress might come from Boeing’s subsidiary, Aurora Flight Sciences, which has begun testing a prototype autonomous passenger eVTOL at its test centre in Manassas, Virginia.
Other than that there’s not much else to say, except it looks great!
Rolls-Royce: eVTOL project
Another vehicle without a name, Rolls-Royce’s eVTOL concept was first unveiled at the 2018 Farnborough International Airshow.
The vehicle will be hybrid-powered with a modified Rolls Royce M250 gas turbine at the rear of the craft powering six electric propulsors specially designed to have a low noise profile. In this configuration it could carry four or five passengers at speeds up to 250mph for approximately 500 miles and would not require re-charging as the battery is charged by the gas turbine.
The concept would be piloted and could use existing infrastructure such as heliports and airports. Its wings rotate from vertical to horizontal configurations to transition from take-off to forward flight and the main turbines could fold away at cruising height, reducing drag and cabin noise, leaving the two tail propellers for forward thrust.
Aston Martin: Volante Vision Concept
Produced in partnership with Cranfield Aerospace Solutions, Cranfield University and Rolls-Royce, the Volante Vision Concept will be a luxury personal eVTOL vehicle for three people.
Using Rolls-Royce’s expertise at hybrid-electric technology, the vehicle will be a hybrid with a semi-autonomous control system developed by Cranfield. The craft will be capable of fully autonomous flight but will re-introduce elements of driver control depending on the skill of the driver, according to an Aston Martin spokesperson.
And it won’t just be for short inner-city hops. The same spokesperson talked of the craft being able to make London to Paris in just one hour.
Aston Martin says it is targeting the aircraft for the urban cityscape of 2030 and that certainly fits with its futuristic and beautiful design.
In 2011, German-based Volocopter’s first prototype, the VC-1, achieved the first manned eVTOL take-off and flight in the world. In 2016 the VC-200 was the first eVTOL to receive a permit to fly alongside regular air traffic. Now the latest iteration, VoloCity, is aiming to become the first manned eVTOL to receive a commercial licence.
The unique design of the VoloCity features 18 rotors distributed evenly around a large ring that sits above the fuselage. The piloted aircraft will carry two passengers with luggage over a range of 35km. It has a maximum cruise speed of 110km/h and its nine lithium-ion battery packs are designed to be swapped out and recharged in just five minutes.
Perhaps most impressive is its safety standards, which meet European Aviation Safety Agency (EASA) requirements stating that air taxis must be as safe as airliners. This could mean the VoloCity wins the race to become the first commercially certified air taxi.
The firm’s VoloPort, a transparent vertiport, will have its first prototype in Singapore. And in cooperation with the operator of Frankfurt Airport, and the German Air Traffic Services, Volocopter is investigating how to incorporate air taxis into airport operations.
Joby Aviation: eVTOL
Another collaborator in Uber’s Elevate programme, Joby Aviation has also received funding and partnership from Toyota. The Japanese car manufacturer invested $394m in the company in January and will offer its expertise in scaling up production.
It’s perhaps not a surprise that two such big players are interested in the small, California-based firm. Joby Aviation has been developing its eVTOL for 10 years now and began flight-testing its prototype in 2017.
The all-electric four-passenger air taxi has some impressive stats. The six tilting rotors can carry it to cruising speeds of 200mph with a range of more than 150 miles. High levels of redundancy mean it is protected against single points of failure and its all-electric powertrain make it 100 times quieter than conventional aircraft.
It seems the craft is designed to be piloted as there is no talk of an autonomous version. This means it could take to the skies in the not-too-distant future, fuelling Joby’s dream of saving a billion people an hour a day.
Terrafugia stands out among the competition in that it has already made one flying car and is on to its second.
Founded by five MIT graduates in 2006, the company’s first offering was the Transition, a hybrid vehicle that drives on the ground like a normal car but can transition in under a minute to a fixed-wing, petrol-powered, two-passenger light aircraft.
Image credit: TF
The TF2 is a more evolved and complex urban mobility solution. The four-passenger vehicle starts as a hybrid-powered ground taxi, which docks on the VTOL aircraft’s frame, attaching the passenger cabin to the aircraft while the driver cabin detaches. The aircraft, plus passenger cabin, then flies to its destination vertipad where another ground vehicle links to the passenger cabin and takes the passengers to their final drop offs by road.
The aircraft section is powered by eight electric engines fuelled by a turbine generator, which the company intends to transition to fully electric in the future. Likewise, the ground vehicle is hybrid-powered with a view to full electrification going forward. Both elements require a driver or pilot but again there is an expectation of full automation in the future.
Hoversurf: Hoverbike and Formula
Hoversurf has the distinction of being the only eVTOL that comes in the form of a bike. The sleek, four-rotor machine carries a single passenger strapped to the outside just like a traditional motorbike.
If the concept sounds slightly insane, well it’s already flying, with appearances at several events including the Dubai Airshow – and it has Federal Aviation Administration approval in the US.
The Hoverbike’s speed is limited to 60mph and safety features include sound and visual warnings and automatic emergency landing. Power is supplied by an innovative lithium-manganese-nickel battery, giving a flight time of 10-25 minutes dependant on weight and weather conditions. A portable home-charging pack recharges the battery in two-and-a-half hours.
Hoversurf has also developed a single-seat air taxi that can park in a standard car-parking space and works without rotors, using instead the company’s own patented Venturi engines, which it claims are quieter and safer than standard rotors. The ‘Formula’ can fly up to 186 miles at a top speed of 155mph.