An Introduction to Advanced Air Mobility and the Future of eVTOLs

Sitting in busy traffic in a major city, you may ask yourself if there's a better way to move through populous areas. What if, instead of being constrained to the ground, we could move in three dimensions and travel short distances through the skies?

While this may seem like science fiction, the idea is not unfounded. Take electric vertical takeoff and landing (eVTOL) vehicles as an example. eVTOLs are small aircraft that can both take off and land without needing a runway, which could enable them to function in tight suburban and urban areas.

eVTOLs will also likely play a major role in advanced air mobility (AAM), which aims to advance the aviation industry via new, efficient, and sustainable crewed and uncrewed methods of transporting people and cargo. AAM will aid many industries, from emergency services to public transportation.

But how exactly will eVTOLs be used to advance AAM, and what challenges and opportunities are innovators in this space dealing with?

A Quick Look at the Current State of AAM and eVTOLs

While the exact timeline of AAM is debatable, Jim Sherman, senior director of aeronautics at the American Institute of Aeronautics and Astronautics (AIAA), says AAM may have started around 2009 with the NASA Puffin project, which was an early-stage eVTOL. Then, in 2010, Joby Aviation began to conceptualize a commercial eVTOL. In the years following, the burgeoning electric flight and vertical takeoff market saw major growth, aided in part by companies like Archer, Vertical Aerospace, Lilium, and Volocopter.

While technologies that are foundational to AAM had been in development for years, it wasn't until around 2020 that NASA invented the term "advanced air mobility" to help direct its research more effectively, says Sherman. Since then, the concept of AAM has grown to include a few distinct subsets, including regional air mobility (RAM) for suburban air transport and urban air mobility (UAM) for air transport at lower altitudes in urban areas via small- and medium-sized drones.

While the initial surge of companies entering the AAM and eVTOL markets has tapered off, a few organizations have become increasingly established, such as Archer, Joby Aviation, and Vertical Aerospace. Of these, Joby Aviation and Archer are aiming to certify their aircraft in the next few years. Another company, OneSky, is developing a low-altitude traffic management system that would facilitate uncrewed traffic management (UTM) and AAM traffic in the same space.

As for eVTOLs themselves, these fit under the wider AAM umbrella and can fit a variety of use cases. For example, the cargo sector presents a very legitimate business case, says Sherman. From making short-duration deliveries to transporting organs to hospitals, there are many potential applications that eVTOLs can assist with.

On the other hand, "the passenger air taxi model is going to take a lot more time to develop," says Sherman. While challenging to achieve, an eVTOL air taxi could make short, quick trips around high-density areas for faster travel. And when the technology further evolves, eVTOL range could improve enough to enable RAM. These taxis could offer unique sightseeing experiences as part of the tourism industry, function as airport shuttles, and more.

In some ways, eVTOLs are a natural extension of existing electric-powered technology, such as what is already found in today's automotive industry. "We can draw a straight line from the days of the Prius right up to where we are today," says Sherman. However, although eVTOLs are well on their way to being an active part of AAM, they have a few key challenges developers must overcome.

Key Challenges for eVTOL Developers

While eVTOLs are an essential piece of the AAM puzzle, they are not yet ready for widespread deployment. According to Sherman and Prem Andrade, distinguished engineer at Ansys, part of Synopsys, the engineers designing and developing eVTOLs have a few major hurdles, including:

1. Ensuring safety. All products must meet existing and upcoming safety standards, such as those from the Federal Aviation Administration (FAA) and European Union Aviation Safety Agency (EASA). "Safety is super critical for advanced air mobility," says Andrade.
2. Maximizing efficiency and sustainability. eVTOLs are more efficient than helicopters, and this benefit will become even more pronounced with continued technological advancement. This will involve designing increasingly efficient power systems and batteries.
3. Minimizing noise. Although eVTOLs are already around 100x quieter than helicopters, it is a priority to continue lessening noise pollution as much as possible.
4. Building infrastructure. eVTOLs will require the creation of vertiports that can handle the strong downward winds created beneath the aircraft (known as downwash and outwash), as well as optimized charging ports for landing on and quickly charging their batteries.
5. Deploying in urban environments. Determining a flight path around and over buildings, handling wind, and finding permissible and appropriate areas for landing and charging stations pose major challenges for urban operation.

These challenges will also evolve over time, meaning that eVTOL developers will need to be adaptable in their designs and plans. For example, EASA announced that they want eVTOLs to be as safe as commercial airliners, says Sherman. This change will require an increase in cost and testing to achieve the redundancy and reliability required.

As another example, the safety standard Federal Aviation Regulations (FAR) Part 23 has gone through many changes in the past 10 years, including becoming less prescriptive and more centered on validation. While no company has yet gone through this new process completely, eVTOL developers like Joby Aviation and Archer will have to navigate this difficulty soon to achieve certification.

To successfully deploy eVTOLs as part of the future state of AAM, engineers will need to balance the technical challenges associated with optimizing their designs, work with municipalities to build infrastructure, and remain flexible to adapt to regulations that may change during their development cycle.

How Can We Accelerate Progress Toward AAM?

While imperative for progress, tackling these challenges is not simple. To aid in this process, innovators worldwide turn to Ansys simulation software to optimize their designs, validate their safety, and build overall confidence in AAM systems.

Optimizing eVTOLs With Ansys Simulation

By using Ansys multiphysics simulation tools, engineers can accurately and comprehensively analyze their eVTOL designs, shortening the time to market and accelerating progress toward AAM.

For example, take an engineer who wants to minimize the sound pollution from their eVTOL design. Using Ansys Fluent fluid simulation software, they can model the pressure waves and acoustics to determine the sounds emitted by each design iteration.

Of course, acoustics modeling is only one way that simulation software can help with design optimization. Other use cases combine electromagnetic, optical, thermal, structural, and aerodynamic simulations for design optimization, structural analyses, battery thermal management, propulsion system optimization, electro-optical infrared (EOIR) sensors analysis, and other evaluations.

Validating Safety and Meeting Safety Standards via Simulation Software

eVTOL designers and manufacturers can also leverage simulation to achieve compliance and certification more quickly and efficiently. Some key uses include:

• Creating digital twins for safety monitoring, such as prognostic health management and maintenance
• Using artificial intelligence and machine learning (AI/ML) solutions to perform lightweight verification runs
• Designing autonomous system safety validation
• Adhering to virtual verification, validation, and certification by analysis (CbA) for existing standards, such as the Guidelines for Development of Civil Aircraft and Systems ARP4754B from SAE International, as well as the Military Standard (MIL-STD) 882E System Safety from the U.S. Department of Defense

"The fact that we can run through multiple test cases and simulations so quickly makes it possible that we're where we are today," says Sherman. Simulation tools help ensure that safety-critical components are safe, reliable, compliant with regulatory standards, and trusted, which is essential for the implementation and acceptance of AAM.

Gaining Confidence With Comprehensive Digital Engineering Tools

By using Ansys' simulation and digital engineering tools, engineers can study an eVTOL's rotors in motion, its mission environment, and other factors to capture the full operational picture.

For example, Ansys Systems Tool Kit (STK) digital mission engineering software can model the complex systems that comprise an eVTOL within a time-dynamic and realistic 3D simulation, which includes high-resolution terrain, imagery, and radio frequency (RF) environments.

Such a comprehensive analysis is essential for detecting issues early in the design process, thereby avoiding potentially life-threatening issues later in development and deployment.

Ansys software can also help with some of the difficulties of operating in more crowded areas that need to balance scheduled flights with on-demand routes for aircraft. With Ansys simulation software, engineers and operators can model air traffic and how it is affected by the presence of eVTOLs.

Andrade says Ansys has solutions that take engineers all the way from mission requirements and concept to design, validation, safety, and operations. This seamless end-to-end digital engineering workflow enables engineers to perform all their analyses in one place, increasing efficiency and saving time and costs.

Looking to the Skies: The Future of AAM and eVTOLs

AAM and eVTOLs have the potential to transform how we think about transportation. This technology may redefine the future of moving people throughout urban and suburban areas, transporting cargo, aiding medical emergencies, and more. In fact, "the global eVTOL aircraft market is expected to reach $23.4 billion by 2030," says Andrade.

A few of the key technologies that are driving the continued advancement of eVTOLs and AAM are:

1. Autonomy. While autonomous systems will take time to be adopted for civilian aerospace applications, "autonomy is extremely important from a defense point of view," says Andrade.
2. Digital twins. Digital twins are helpful "across the board, with things like prognostic health management and looking at the health of your asset as it's flying," says Andrade. The main benefits of digital twins can be divided into two buckets:
   • Employing a digital twin during the design and development process to efficiently and accurately study and refine your design in a virtual environment
   • Using a digital twin after the design goes into operation to better assess abnormalities, compare preventative measures, and more
3. Over-the-air (OTA) updates. With increasingly complicated designs that are involved in critical missions, performing regular updates and ensuring continued functionality and compliance can be difficult. With OTA updates, engineers can implement software updates on vehicles in the field, enabling continuous improvements.

Looking to the future of AAM and eVTOLs, "I want to see it establish itself as a legitimate industry," says Sherman. He envisions a future in which everyone can afford to ride in eVTOLs that are efficient, evolving, and, most importantly, useful.

To learn more, watch the webinar "Leveraging Digital Engineering for eVTOL Design and Operation" and download the e-book "Navigating Tomorrow's Skies: Confidently Developing Autonomous Systems."

Just for you. We have some additional resources you may enjoy.

TAKE A LOOK

"The fact that we can run through multiple test cases and simulations so quickly makes it possible that we're where we are today."

- Jim Sherman, senior director of aeronautics, American Institute of Aeronautics and Astronautics