What are electric vertical take-off and landing (eVTOL) aircraft?
Electric vertical take-off and landing (eVTOL) aircraft take off vertically like a helicopter. The key difference is that they are powered by electric motors instead of conventional combustion engines. Propellers or rotors ensure they can take off vertically, hover in place, and fly horizontally.
How does the technology of these aircraft work?
eVTOL aircraft fly through electric propulsion and vertical lift. Electric motors drive rotors or propellers arranged in different configurations — typically, they are static and fixed in place or can tilt for lift and control in all directions.
Batteries, typically lithium-ion, or other energy storage systems store and provide the energy needed to lift off and fly. The aircraft are controlled by computer systems and, if they are not fully autonomous, pilot input.
Are eVTOLs already a reality?
eVTOL aircraft are in the development and testing stage, and several prototypes are at different stages of flight testing. So while they are not quite a reality yet, the groundwork and drive are there. Research firm MarketsandMarkets says the eVTOL market is expected to reach a value of over $30 billion by 2030, a compound annual growth rate of 15.3 percent from 2023.
According to Archer CEO Adam Goldstein, briefing Aviation Week after a visit from the FAA, certifying eVTOLs by 2025 is now one of the FAA’s top three priorities. Additionally, the FAA is very focused on having eVTOLs used “at scale” in Los Angeles for the 2028 Olympics. We could be seeing eVTOLs in use sooner than many might imagine!
Are they safe?
As research and development proceeds in the eVTOL sector, safety is a key consideration. This is true both in development and during flight testing, during which aircraft are pushed to the max to see how safe and reliable they are in real-world conditions.
The FAA is working toward standards for advanced air mobility, which includes eVTOL aircraft. The FAA determines the certification requirements for each eVTOL’s design, production, airworthiness, and operation. They are also working on operator certification, infrastructure development for ‘vertiports,’ and a conceptual framework for operations around urban areas.
Safety features include redundant propulsion and flight control systems, advanced sensors and avionics, and fail-safe mechanisms for a safe landing.
What is the societal impact of widespread use of eVTOL aircraft?
From infrastructure opportunities to accessibility, eVTOLs have the potential to revolutionize many key aviation functions.
Could they reduce traffic congestion in large cities?
Taking little space to take off and land and offering quick transportation, eVTOLs could reduce traffic congestion in large cities. People can stay off congested roadways and bypass gridlock by taking to the sky. This also plays a part in addressing air pollution and gets people to where they need to be with less travel time and fewer delays.
Will eVTOLs make transportation more affordable/accessible?
eVTOLs have the potential to make transportation more affordable and accessible. They may reduce the need for runways and airports and for using congested roadways. eVTOLs can take off like helicopters, meaning they can travel from rooftops and other flat surfaces with a much smaller footprint.
As for affordability, there are different predictions, from $2.25 per passenger per mile up to $11. The infrastructure and technology required to build and operate an eVTOL are currently high, from charging stations to maintenance facilities. Pilots, training and autonomous technology are other significant costs to factor in.
Like any new technology, there may be a period where eVTOLs are not widely accessible or affordable to all until the tech becomes more widespread and reaches a critical mass. This is similar to electric vehicles, which are now becoming more affordable to the average consumer.
Could they replace helicopters?
eVTOLs are similar to helicopters but are quieter, produce zero emissions, and can take off and land vertically. They could potentially serve to replace helicopters or augment service in urban areas. However, eVTOLs, as they are right now, will likely not have the full range or payload capabilities of helicopters. Until technology improves, we may see eVTOLs replace or complement helicopters in some limited applications but not in all scenarios.
What is the environmental impact of widespread use?
eVTOL aircraft have the potential to reduce pollution and greenhouse gas emissions if powered by renewable energy sources. While eVTOLs themselves produce no emissions, charging their batteries using conventional power sources can still produce emissions. As eVTOL aircraft become more commonplace, any positive environmental impacts may begin to be realized.
Will they help reduce pollution and improve air quality?
eVTOLs can potentially reduce pollution and improve air quality, especially if renewable energy sources power them. Because they are not powered by fossil fuels and instead use electric motors, emissions are cut down completely, reducing air pollution and improving population health.
Will they play a role in reducing greenhouse gas emissions?
eVTOLs require batteries to operate. If eVTOL batteries are charged by renewable energy sources like wind or solar power, they could reduce greenhouse gas emissions vs. typical applications that do require fossil fuels. Research says that comparing an eVTOL loaded with three passengers versus a ground-based car with an average occupancy of 1.54, eVTOL greenhouse gas emissions per passenger-kilometer are 52 percent lower than internal combustion engine vehicles and 6 percent lower than electric vehicles.
Are they still in the development stage?
Right now, eVTOLs are limited by range and payload capacity. For example, the range of eVTOL aircraft is estimated at 50 miles initially, while the longest-range helicopters can fly as far as 500 miles in a trip.
Being in the development stage, eVTOLs also require a significant investment in infrastructure, which will take time. As discussed above, the cost of operating, building, maintaining and using an eVTOL will also be higher while they are in these initial stages. They will also require regulatory approval, adding more time to the process.
Could they disrupt air traffic control systems or cause congestion?
eVTOLs could possibly be disruptive to air traffic control systems without changes to the way these systems currently operate. There is already high air traffic density in urban areas where eVTOLs are expected to be widely used. In addition, eVTOLs operate at low altitudes along with other conventional aircraft. These factors impact the potential for congested urban skies.
Technology like sensors, communication systems, and data processing algorithms will help, along with integrating eVTOLs into air traffic control systems with new procedures and protocols.
Do their electrical engines cause emissions?
While battery-powered eVTOLs produce no emissions during operation, charging the batteries used to power them can cause emissions. If the electricity used to charge eVTOL batteries is generated from renewable energy sources like solar or wind, eVTOLs may be entirely emissions-free. However, if electricity comes from conventional sources, some emissions and greenhouse gasses would still be a by-product.
Ultimately, electric engines do not cause emissions on their own, and even batteries charged with conventional power produce fewer emissions than fossil fuel-powered aircraft.
How does battery tech relate to the progress of eVTOLs?
Battery technology is a key component of the electric propulsion system that powers eVTOL aircraft. So, battery technology is critical to the progress of eVTOLs and a significant factor in moving aircraft from research and development into reality. eVTOLs will likely depend on high-capacity, energy-dense, lightweight batteries to ensure safety, reliability, range and payload.
Battery safety and reliability are also important, with a need to avoid both fire and failure. Battery management systems are important, and batteries must be stress-tested in research and development. eVTOL batteries may be subject to extreme temperatures, high altitudes, and rapid charge and discharge cycles and must remain safe and functional.
Along with energy density, battery cost is among the most important factors for eVTOLs. Much like electric vehicles, battery cost drives the overall cost of eVTOLs. As battery technology improves and achieves economies of scale, costs may be reduced, and eVTOLs may become more affordable and accessible to a broader range of people.
How does energy density factor in?
The energy density of a battery measures how much energy it can store in a given mass or volume. Higher energy density batteries can store more energy in a smaller or lighter battery. eVTOL vehicles require a high amount of energy to lift off the ground and fly. So, the energy density of batteries directly influences the capability and range of an eVTOL and its usefulness.
An eVTOL with little range and payload capability may have limited practical use. Particularly when we look at using eVTOLs to replace helicopter functionality, batteries and energy density are critical to ensure transportation works.
The energy density of a battery enables a greater eVTOL range with fewer stops to recharge or replace batteries. With energy-dense batteries, eVTOLS may fly longer, carry more passengers and cargo, and become a more efficient method of transportation.
What companies are working on eVTOLs now?
From prominent, well-known names in aviation to smaller startups, many companies are working on research, development and testing of eVTOLs. By Q2 2022, there were over 500 concepts in the works, according to Simple Flying. Here are a few examples.
Airbus – In September 2021, Airbus unveiled its eVTOL prototype CityAirbus NextGen. It has a range of 80 kilometers and a speed of 120 km/hour, designed to be deployed in urban areas and used for transporting passengers, eco-tourism, and medical missions.
The company recently began constructing a test center for the CityAirbus NextGen, which is scheduled to be completed soon.
Archer – Archer’s Midnight five-seat eVTOL aircraft carries four passengers and one pilot for up to 60 miles at speeds of up to 150 mph. The company plans to focus on markets with heavy traffic congestion initially.
Joby Aviation – Joby Aviation is developing a five-seat eVTOL aircraft for urban applications, designed with a range of 150 miles. The company recently announced a project to operate demonstration flights with a partner during the Expo 2025 in Osaka, Kansai, Japan. Joby became the first foreign air taxi manufacturer to formally apply for its aircraft design to be certified for use in Japan in October 2022.
Joby is believed to be the first eVTOL company to test its propeller in the National Full-Scale Aerodynamic Complex 40-by-80-foot wind tunnel. It registered what it believes is the fastest eVTOL test in history at an airspeed of 205 miles per hour. The company has ambitious plans to begin delivering commercial passenger services in the United States in 2025. It has completed more than 1,000 test flights since its establishment in 2009.
Beta Technologies – An all-electric propulsion system powers Vermont-based Beta Technologies’ electric Alia-250 aircraft with vertical takeoff and landing capability. The eVTOL operates with a noise profile one-tenth the decibel level of conventional helicopters, a big consideration for urban use, and it can fly up to six people. In April 2021, Blade Air Mobility announced an agreement to facilitate the purchase of up to 20 of BETA’s first passenger-configured eVTOL aircraft by its network of operators, intending to deploy these aircraft on routes between its terminals in the US. BETA has also agreed to provide and install charging infrastructure at critical locations.
What must be addressed before eVTOLs are widespread?
There are a few key areas that need more information and more investment before eVTOLs can become widespread.
The first is infrastructure, from landing pads to charging stations to maintenance facilities. We have seen this before with electric vehicles, which initially had little supportive infrastructure for consumers. Infrastructure must follow as demand for eVTOLs increases and the technology becomes more commonplace.
Safety and certification are also vital for companies working with organizations like the FAA for regulation and ensuring public confidence in newer technology.
Airspace management, noise pollution, and addressing potential congestion are crucial to public understanding and adopting new technology. If people in urban areas feel unfairly impacted, they are unlikely to accept the benefits of eVTOLs happily.
The cost will remain a factor that will need to be carried by companies, investors, and those who can afford to fly with eVTOLs until infrastructure is built, prices come down, and use becomes widespread enough that it is more accessible.
And, of course, battery technology is essential. As battery technology develops and improves, so will eVTOL technology. High-capacity, energy dense, lightweight batteries are crucial and will significantly impact the performance, reliability, and accessibility of eVTOLs.
