HAI Convention News

Hirschberg: eVTOL Is Urban Moonshot

 - January 29, 2020, 4:09 PM
Mike Hirschberg the executive director of the Vertical Flight Society.

Mike Hirschberg is the executive director of the Vertical Flight Society (formerly the American Helicopter Society), an organization deeply involved in the science and research driving electric vertical takeoff and landing (eVTOL) aircraft and urban air mobility (UAM). Hirschberg was previously a principal aerospace engineer with Centra Technology, providing technical and program management support for more than 10 years to the Defense Advanced Research Projects Agency (Darpa) and Office of Naval Research (ONR) on advanced aircraft and rotorcraft concepts. Before this, Hirschberg worked from 1994 to 2001 in the Joint Strike Fighter (JSF) program office, supporting the development of the X-32 and X-35 vertical flight propulsion systems. Hirschberg holds a bachelor's degree in aerospace engineering from the University of Virginia and a master's in mechanical engineering from Catholic University of America. AIN sat down with Hirschberg at Heli-Expo 2020 to discuss the future of UAM.

Two factors set eVTOL aircraft apart: electric power and autonomous operation. Which of these do you feel will prove to be the most transformative for aviation and which of these is the most challenging for the industry to deliver?

The real revolution for urban air mobility is electric power. With electric power, you can distribute the propulsion to thrusters around the aircraft. So you’re able to come up with configurations that just couldn’t exist with driveshafts on mechanical systems. Using electric power on vertical takeoff and landing designs that transition to winged flight for high cruise speed allows for less power consumption. You can use a battery to get off the ground and then require much less power for cruise. So that combination is a way to get over the limitations of battery power in a helicopter or a multi-copter that has to thrust down the whole time.

Autonomy is very important. Obviously you can get much more efficiency and throughput by having all the seats occupied by passengers.

Uber Elevate said at one point they expected these vehicles to cost less than $200,000 and expected to deliver UAM service for around $1.36 per seat mile. Given the likely cost of the vehicles and the infrastructure to support them, is this realistic? 

We know that electric aircraft can be much cheaper to operate than piston- or turbine-powered aircraft, just like an electric car is cheaper to operate than a fuel engine. So we think the operations will be cheaper without some of the complex mechanical systems, we think the vehicle will be cheaper to produce. The actual seat miles that Uber quotes—that’s maybe in the farther future as learning improves, higher volumes are produced, and the aircraft get cheaper and different systems are in place.  

Will we ever see UAM truly become a mass market, or is this likely to be a premium transportation service with a limited market?

I think it will be in the middle. Urban air mobility is just one more option, just like today we have taxis, Uber, scooters, public transportation, driving, and walking. Just having more options for travelers will help distribute loads. When ground traffic is congested, aircraft and other methods will be used to commute across town. I think a lot of people can travel on eVTOLs.

Uber is looking at thousands of flights per day. But there are only going to be four or five seats per aircraft, so it’s not going to solve congestion. It will provide more opportunity for people, depending on the price point and the wait. If you have to wait longer to get a ride, it’s really not going to make people happy either. People are going to take the path of least resistance. It’s not going to be a premium service, but it’s not going to be a solution for congestion of something that will have a mass-market, either, at least not in the foreseeable future.

Of the 252 odd eVTOL designs announced to date, in your opinion, how many are currently properly capitalized through certification and initial production? 

No company that I know of is capitalized through certification and initial production. Joby Aviation has gotten the most money we know of so far. They’ve raised $720 million in total and have been working at it for 10 years and flying for three years. The money is probably enough to get them through certification, but as far as building things up for production, they’re going to require more money before they get a return on investment. The next tier of companies, such as Volocopter and Wisk, are in the $100 million range. There are a few more companies that are near that, but it is expensive to certify an aircraft, put it into production, and get a return on your investment.  

What’s your takeaway from Toyota’s recent large investment—nearly $400 million—in eVTOL maker Joby Aviation? 

Toyota has invested in a company with a compelling design that balances the high power required for vertical takeoff with the lower power required for cruise flight. Toyota’s investment in Joby suggests it is a leading contender in eVTOL, with a design that is very elegant that Toyota believes will be a market winner. 

Given the current state of battery technology and the limited flight duration it achieves, does the FAA need to waive the 20-minute VFR reserve rule, currently in place for helicopters, for eVTOLs to be economically and practically viable? 

No, they shouldn’t. Helicopters can land anywhere, but they still have to have reserve fuel, and the same for eVTOLs. Just because they can land anywhere doesn’t mean you shouldn’t have reserve fuel. They should have sufficient capability to divert to a different site or land safely in an area. That might not be 20 to 30 minutes of fuel reserve, but it should be enough to make them safe. 

How will the 737 Max grounding impact the regulatory environment and how will that affect the pace and scope of eVTOL regulation, and ultimately the certification of eVTOL aircraft? 

I’m not sure it will. But the scrutiny of the autonomous assistance program—such as MCAS (Maneuvering Characteristics Augmentation System) on the 737 Max—is producing greater scrutiny for autonomy, and we’ve also seen this with greater autonomy in helicopter cockpits such as in the Bell 525 and with Airbus. It’s a new capability we haven’t had in the helicopter industry until recently and as people understand it, its ability and limitations, those will be applied to urban air mobility as well. Autonomy will be a key benefit for eVTOL and will increase capacity once you do not need a pilot on board.  

More states and localities are becoming increasingly aggressive about regulating helicopters. Will this climate will carry over to eVTOLs? 

We know that eVTOL aircraft are inherently quieter than helicopters. We believe because they are quieter, there won’t be as much citizen push back as there would be with regard to helicopters. The goal of eVTOL developers is to get the noise of the vehicles to blend into the background noise of the environment. However, multiple flights out of vertiports all day, every day, will create a certain amount of visual pollution.

But when you look at the benefits that eVTOLs provide a community, when more people start to use it, we think citizens will be more receptive to it. There isn’t going to be a case like helicopters, where very few people use the technology. We’re working with different organizations to build community acceptance and educate state and local governments on the benefits of UAM so they can plan for it and take advantage of the benefits it offers. 

Where will we first see regular UAM service? In the U.S. or somewhere else? 

EHang in China might receive approval this year. Volocopter has flown a couple thousand flights and they are working on getting approval in Germany and Singapore. Uber is planning for 2023. Joby also expects 2023. I think it will start out modestly—maybe just one flight per day. But as operators work out the hiccups and build experience, it will build and expand, first in the U.S. in Dallas and Los Angeles. But in 10 or 20 years, this is going to be a very big part of our lives. 

Where do you see the largest market potential—cargo/delivery or passenger UAM? 

Cargo development is obviously easier because you don’t have passenger-safety concerns. But passenger transport will be much more lucrative than cargo delivery, so there is more investment in air-taxi designs. 

What do you see as the major eVTOL development for the rest of 2020? 

People will see some of these aircraft fly this year and other manufacturers unveil their designs. Once people see these aircraft fly and their capabilities, they will begin to appreciate what they can do. 

And what do you see as significant developments for the remainder of the decade? 

For eVTOL to be worth the investment they really need larger-scale operations. When tens of thousands of people are flying every day in a city, then there will really be a benefit. We’ll see more cities around the world adopt UAM services and those will scale up in terms of the number of cities, vertiports, aircraft, and passengers.

What is the most valuable role the Vertical Flight Society plays in the UAM market?

In 2013 we saw the confluence of technologies that would enable the eVTOL revolution. We started having workshops in 2014 with developers; NASA; standards organizations such as ASTM and SAE International; and different aviation organizations over the years in trying to support aircraft builders and researchers. We’ve tried to play a key role in bringing people together. We’ve just had our seventh eVTOL symposium that attracted developers, scientists, investors, insurers, and government agencies from all over the world.

We also hold specific workshops, conferences, and publish technical papers on the specific benefits of eVTOL aircraft. This eVTOL revolution is really exciting, but it really requires a lot of collaboration. It’s like going to the moon. Everyone has to come together and look at the different roles people can play. We really think there is going to be a huge benefit to society in bringing UAM to cities.