Two important new urban air mobility concepts took center stage at the Consumer Electronics Show in Las Vegas in January—concepts that could significantly shape the future of flying taxis.
Hyundai-Uber
Hyundai and Uber have collaborated to create the Hyundai S-A1 aircraft for the ridesharing service.
The S-A1 uses eight rotors—four in a fixed position to boost downward air flow while hovering, and four that can tilt for horizontal or vertical flight to propel the aircraft around the city. It can reach a cruising speed of 180 miles per hour and a cruising altitude as high as 2,000 feet while making trips up to 60 miles.
The vehicle will be 100 percent electric and could be charged in as little as five to seven minutes during busy stretches of the day. It will use distributed electric propulsion to get around, powering several rotors and propellers. This will not only increase the safety of the aircraft should a rotor fail, but it will also be much quieter than conventional rotor craft—an important consideration in cities. The S-A1 will take off and land vertically, transitioning to wing-borne lift to cruise between destinations.
Hyundai’s flying taxi will accommodate four passengers with enough room for a personal bag or backpack. It will initially be piloted, but the carmaker intends to eventually make the S-A1 fully autonomous. .
The partnership between giant automaker Hyundai and Uber could be a game changer in the new but growing urban air mobility market.
“Combining Hyundai’s manufacturing muscle with Uber’s technology platform represents a giant leap forward for launching a vibrant air taxi network in the coming years,” said Eric Allison, head of Uber Elevate.
The SA-1 forms part of a larger urban air mobility concept that includes a landing pad building called a Hub and a fleet of electric Purpose-Built Vehicles that would transport people between the hubs and existing transportation infrastructure.
Bell
Helicopter manufacturer Bell is also investing in the urban air mobility sector with a smart city ecosystem centered around its Nexus 4EX aircraft. Originally debuted at CES 2019, Bell has since refined its powered-lift aircraft concept.
The Nexus 4EX features four tilting ducted fans—two less than the previous Nexus version to reduce drag and cruise more efficiently. It would have maximum takeoff weight of about 3,200 kilograms and a cruising speed of 241 km/h. The flying taxi would make trips 13 km to 22 kmin length.
The aircraft will come in two variants: an all-electric vehicle for shorter hops and a proposed hybrid for longer trips. The electric Nexus 4EX has a range of 52 nautical miles. The hybrid would use a turbo-generator to charge batteries that would power the electric motors, which would boost its range to 130 nautical miles.
The 4EX will have a four-to five-passenger capability plus a pilot. Like the Hyundai S-A1, Bell envisions that its aircraft will eventually be autonomous.
Its battery is being supplied by Electric Power Systems, which will include a battery management system that will monitor temperature, current, voltage, discharge and charge rates.
Bell is deliberately focusing its 4EX design on inner city travel rather than longer trips—a significant departure from Bell’s traditional focus on helicopters that are designed as multi-purpose utility vehicles.
Bell has also partnered with Uber, but the helicopter maker seems committed to providing its own infrastructure and aircraft management technologies to support its urban air mobility concept. Mobility as a Service (MaaS) focuses on making flying taxis more accessible by integrating on-demand air mobility into communities. This service is powered by Bell’s proprietary AerOS fleet management system—a technology running on Microsoft Azure that manages fleet information, aircraft performance, maintenance, and repair, among other factors.
The urban air mobility demonstrations at CES 2020 showcase the promising growth of the sector but significant hurdles still need to be cleared before flying taxis become a part of everyday life. The FAA has not formalized regulations for certificating eVTOL aircraft or rules for inner city autonomous flights—a regulatory structure that vehicle makers like Hyundai and Bell will rely on to finalize their designs.
Another important roadblock is battery capability. Current batteries are too heavy and their energy density is still too limited for an eVTOL to use reliably. Manufacturers anticipate that regulatory requirements for these batteries will be understandably high and will include a mandatory reserve flight capability while carrying passengers.
Encouragingly, though, battery efficiency continues to improve.
“The battery energy power densities right now are right on the edge for a mission like this,” said Scott Drennan, Bell vice president of innovation.
Drennan anticipates that battery energy density could improve up to 15 percent by the mid-2020s. That’s when he thinks the flying taxi industry will reach the critical mass needed to become a reliable and affordable reality. Bell predicts that hundreds or even thousands of flying taxis would be needed in a city to significantly alter conventional ground traffic patterns.
Uber also anticipates that the urban air mobility sector will require a serious re-thinking of the way transportation works—from manufacturing to urban design—and the vehicles themselves are only a part of the equation.
“Electric aircraft manufacturing needs to be fundamentally different from how aircraft are manufactured today,” said Nikhil Goel, Uber’s head of product in its aviation efforts. “That’s what will get us to an accessible cost-per-trip for air taxi flights.”
Read more about urban air mobility technologies at NASA Receives First All-Electric Aircraft, Readies It for Flight.