AAM Spotlight: Rob Scholl, Textron eAviation

Formed in April 2022 following Textron’s acquisition of Pipistrel, Textron eAviation is focused on developing electric aircraft, including the Nexus electric vertical takeoff and landing (eVTOL) air taxi program, which was taken over last year from Bell. Rob Scholl, the unit’s CEO, recently sat down with the AAM Report to discuss the vehicle’s design and development progress. A partial transcript follows.

AAM Report: When do you plan to have a Nexus demonstrator?

Scholl: We are targeting within the next two years to be flying aircraft. We’re keeping the time frame flexible because we continue to uncover new technologies and things that we think will make a better aircraft. We’re still targeting late this decade for an EIS [entry into service]. We’re not giving a specific date because we think it’s going to be driven by regulations, economics and technology—and we’re going to make sure we invest efficiently, because that’s what our shareholders require us to do. We understand that aviation tends to be a marathon, not a sprint, so we’re trying to pace ourselves appropriately from an investment standpoint.

With a maximum takeoff weight of 8,000 lb., the Nexus is quite heavy relative to other eVTOL designs. Why?

So, basically, the airframe and basic systems of the aircraft need to weigh a certain amount, and we understand what that has to look like to get through certification. We think we also have a good understanding of battery cell technology today, and where it’s going to migrate over the next five or 10 years. And I believe that’s going to lead to heavier battery packs to give our end customers something that will really work for them and their operations. You can’t be replacing these batteries on a very regular basis. You’ve got to give them more life cycle, so that you’re not overhauling or completely replacing batteries every couple weeks or months. So, we want to offer up that robust cell life cycle to give a good performance, and it’s my belief that to do that, the aircraft needs to be heavier.

What was the reasoning behind the switch last year from the ducted-fan concept to the tiltrotor design?

The ducted-fan design was originally part of an effort to keep the noise levels down, because there was a belief they were quieter. I also think there’s a perception that ducted fans are a little bit safer. But when you look at the power requirements, a ducted fan does require more power to give you the necessary lift. And in this space for eVTOL aircraft, it’s all about power requirements, right? The power phase when you’re in hover or takeoff and landing is incredibly high. And open rotors allow you to reduce those power requirements. And then can slow the rotors down enough where you can reduce the noise levels too. So for us, it was the overall power requirements that drove the switch to an open rotor design from the closed.

The Nexus is being designed to be fully electric. Why didn’t you go with a hybrid eVTOL like many others?

Well, let’s start with the end customer. They go from having one propulsion system that has to be maintained to two propulsion systems with a hybrid design. And so, how often will the battery or the electric propulsion system have to be overhauled? And the same goes for the gas-powered propulsion system. Then there’s the pure economic piece of it, the cost to the customer of putting two propulsion systems in one aircraft. And there’s also regulatory challenges around how those two aircraft systems interact. So, we’re looking at both paths, but right now we’re working on the full electric to go after that UAM [urban air mobility]-type mission. We also see other potential areas that it could fulfill, but we’re really focused on that urban air taxi model.

What do you see as the major gating factors that could slow the path to adoption for eVTOLs?

I see two major obstacles. The first is infrastructure. And not so much ground infrastructure, because we have enough of that in the U.S. to support early entry into service, whether you’re operating from heliports or airports. But what I think we need to focus on, frankly, as a country, is airspace infrastructure. How do we make more efficient use of our airspace? If we cleaned up some of our airspace now and more effectively used it, we could have a dramatic impact on fuel usage and carbon footprint. There’s also the question of how to communicate with these aircraft and integrate them. Ultimately, I think economics is another big challenge. We’ve got to build an aircraft that’s got a reasonable acquisition cost and a reasonable operating cost and can be flown without too much downtime. So you’ve got to work out the technological challenges early on, and that will take time. But I see those as the two biggest challenges.