Rapid innovations in computing, electric motors, and battery technology are turning the dream of Electrical Vertical Take-off and Landing (eVTOL) aircraft into reality, says a new report by IDTechEx.
The report, "Air Taxis: Electric Vertical Take-Off and Landing Aircraft 2021-2041", reveals the potential of eVTOL aircraft to cut journey times between poorly-connected places in a way that’s affordable, green, and quiet enough for use as air taxis in cities.
Top eVTOL developers like Beta Technologies, Wisk Aero and Joby Aviation are getting closer to flight certification. They plan to mass-produce eVTOL aircraft at over 10 times the volume of mainstream aircraft manufacturers.
With over $4 billion already invested in the eVTOL aircraft market, upcoming IPOs by start-ups Lilium, Joby Aviation, and Archer Aviation are expected to raise another $3+ billion in capital. And big-name aerospace suppliers like Honeywell and Rolls-Royce are already developing technologies for the emerging market.
Perhaps the most vital of these is battery technology. While eVTOL aircraft can work with today’s batteries, which have a maximum energy density of about 180 Wh/kg, doubling that number would massively improve the operational flexibility, range and endurance of air taxis. Ultra-fast charging will also be needed to minimise downtime between flights.
In the meantime, OEMs are exploring alternatives like hybrid or fuel cell-hybrid powertrains, using either fuel cell systems or normal aircraft turbine and piston engines as generators that can charge the battery in flight. While there are still some environmental issues to address around hydrogen production, this would enable air taxis to boost their capabilities while keeping emissions low.
Electric motors are also vital in eVTOL design, with one aircraft often boasting at least six motors, which have to be light but able to meet high power demands during take-off and landing. Axial flux ('pancake’) motors, which have 3 or 4 times the power density of the radial-flux motors used in cars, are currently being explored.
Lightening the aircraft itself as much as possible will also be necessary to maximise range and payload. Carbon fiber composites are the materials of choice, offering many opportunities for manufacturers.
New infrastructure must also be built for air taxis, such as vertiports, booking systems and traffic management systems. Robotics and smart factories will be needed to keep up with the pace of production and maintenance.
Although some challenges remain to be overcome, eVTOL aircraft offer lucrative opportunities for companies willing to take the risk of investing in them.