It’s a sign of the times at this year’s EAA Airventure. For the first time, the Airbus booth near the flight line does not exclusively feature one the company’s sleek production helicopters on static display, but rather the second prototype of its tandem tilt-wing Vahana eVTOL. A single-seat urban air mobility demonstrator, the futuristic vehicle features eight 45-kW electric motors. It's drawing more foot traffic than any of the company’s helicopters ever did.
Despite the excitement, Amanda Simpson, Airbus Americas vice president for research and technology, cautions that it will be some time before such vehicles are commercially viable or economically sustainable in a way that appeals to a mass market.
“There are limitations as to what we can do with batteries,” she said. “If you took the best battery today and made it five times more efficient and you wanted to make an [all electric] airliner the size of an [Airbus] A320 [passenger jet], it would weigh six times as much as the aircraft of today without even putting any passengers or cargo on board. The [UAM prototype] vehicles that are out there have a range of about 30 miles. Try to get more than 30 minutes to an hour out of a vehicle the size [of the Vahana] is very challenging today. And the battery technology is going to have to come along much further if we are going to have 100 percent electric vehicles.” She added that Airbus is continuing its exploration into improved battery technology.
However, battery capacity is only part of the problem, Simpson said. “The challenge isn't the energy density as it goes to weight and volume, but also the charging challenge. There’s only so much energy you can pump into these things over a given period of time. You have to be able to recharge these vehicles when they land. Does that mean swapping out batteries or plugging it in? Where is that energy coming from? How many times can you recharge a battery before you can’t get the maximum utilization out of it? It’s very easy to measure fuel left in a tank, not so much to determine how many megawatt-hours are left in your battery.”
Simpson, like others within the aircraft industry, thinks the first generation of UAMs will have to be hybrids. “I don’t see any other way around it. Remember when [electric car maker] Tesla first proposed battery swap-out stations and replacing entire vehicle battery packs in like three minutes so you didn’t have to wait for 25 minutes or 40 minutes for a charge? It didn’t work out. What the hybrid offers is efficiency, either for boost or distributed power.”
Aside from the battery issue, there is also one of commercial viability. Simpson doesn’t think that urban air-taxi models, which assume passenger per seat mile costs will be on par with those of the family car, are particularly realistic. Then there is the not inconsequential matter of public acceptance as it relates to autonomous air vehicles to transport passengers. The Vahana is designed to be operated autonomously without a pilot in the aircraft or any accessible flight controls in the cabin. A single touchscreen is used to conduct passenger safety briefings and to confirm a passenger’s destination and if he or she is ready for takeoff. Simpson says some potential passengers who have visited the aircraft this week at Airventure find that disconcerting. “People are reluctant to get in vehicles without visible flight controls. It’s a leap,” she said.
There are other safety-related issues as well. Simpson points out that Airbus and a handful of other companies exploring the UAM market have solid aircraft building experience over several decades but that most of the market entrants do not. “It’s only a matter of time before a company new to building aircraft has an accident and then it will raise the bar for everyone else. Here at Oshkosh, in part, we celebrate the Golden Age of aviation. However, when you look back at that age, we killed a lot of people. But there was such enthusiasm that it continued, and the fallout was that it took a long time before people were willing to get on airplanes as part of a scheduled service.”
Still, Simpson thinks UAMs have market appeal, but perhaps not in the way currently envisioned. Personally, she thinks that UAMs will take hold in the Asia Pacific region first, where population densities are higher, regulatory barriers are lower, and governments are often unfettered by the need for democratic debate on public policy. That is not to say that the vehicles will not find a market in the U.S., but initially she thinks that could be more rural than urban, with UAM vehicles proving their worth and safety for medevac and human organ transport and the delivery of expedited goods to ground shipping hubs, before being deployed in more populous areas.
Meanwhile, the lessons from more than 100 test flight hours of the Vahana are being evaluated by Airbus’s new urban air mobility unit in Germany. “The aircraft itself was never the objective,” Simpson said, but rather a vehicle to learning and evaluating the technology. “The question is how to demonstrate the capabilities of the aircraft and how do we work with EASA or the FAA to develop regulations to govern these? How do you work with the cities and the urban infrastructure to provide landing places? How do you develop an app for your phone that will allow you to call and schedule service and the whole infrastructure behind that?”
The answers to those questions will shape Airbus’s decisions when it comes to urban air mobility. Meanwhile, a larger Airbus UAM demonstration vehicle, the four-passenger CityAirbus, began its flight test campaign in May.
Watch an AIN video interview in which Eduardo Dominguez-Puerta, head of Airbus' Urban Air Mobility division, talks frankly about the challenges and opportunities facing those trying to bring eVTOL aircraft to market.