An Experimental Test Pilot’s Look at Electric Aviation

For decades, discussions of electric flight have inspired images of peaceful, eco-conscious air travel. Electric flight promises fewer carbon emissions and lower fuel costs, and while obstacles remain before that potential is realized, promising research is underway. In a recent presentation hosted by Acubed, accomplished experimental test pilot Miguel Iturmendi discussed a variety of experimental electric-powered projects and the paths they face toward commercial certification.

Iturmendi, who has accrued more than 10,000 flight hours, has set multiple aviation world records and contributed to the development and testing of an array of experimental aircraft like the Helios Horizon, SolarStratos, and the Airbus Perlan II, among many others. His enthusiasm for an electric future was obvious, and he spoke candidly about getting there.

New Designs, New Standards

Because most electric applications are new – compared to traditional aircraft – and vary significantly in both function and appearance, there may be little or no standardized path toward certification from the Federal Aviation Administration (FAA) and the European Authority for Aviation Safety (EASA), and airworthiness is often determined on a case-by-case basis.

“It makes sense … that the FAA and EASA are doing it this way,” Iturmendi said. “Because, quite frankly, all these vehicles … are one of a kind.”

Despite singular designs, these experimental electric aircraft generally fall into a handful of categories.


Electric vertical take-off and landing (eVTOL) aircraft – typically featuring multirotor designs – are the result of developing solutions for passenger and cargo transport at low altitudes in populated areas, a concept known as urban air mobility (UAM). Acubed’s Vahana eVTOL, for example, features eight electric motors and a tilt-wing design, achieving both vertical take-off and landing, as well as urban flight powered entirely by batteries. Ultimately, Vahana helped enable researchers to explore the operating costs and potential path toward certification for commercial eVTOLs.

Iturmendi was frank about the need for improved battery technology, among other improvements, in order to support commercial eVTOL deployment, though. “All of this will happen eventually,” he said. “It will just happen farther down the road.”


From fixed-wing to hybrid helicopter designs, electric short take-off and landing (eSTOL) aircraft require less energy to take off and land, compared to eVTOLs, and are capable of doing so on shorter-than-average runaways.

Regarding eSTOLs, Iturmendi said, “They have a better chance to be certified, because any time you can catch some lift with your wings you’re by definition safer since you can fly really slowly and still bring it to the ground.”

Fixed-Wing Solar

Solar-powered aircraft typically feature wide wings and lightweight construction and have demonstrated the longest range of emerging electric aircraft. They are limited in their ability to convert solar energy to power, however, resulting in slower cruising speeds.

Airbus’ Zephyr fits into this category. Zephyr is a world-record-breaking High Altitude Platform Station (HAPS). Capable of flying continuously for months at a time above weather and conventional air traffic – around 70,000 feet – Zephyr relies on solar energy, with secondary batteries charged during daylight to power overnight flight.

Hybrid Electric

Hybrid approaches utilize both electricity and aviation fuel either jointly or alternately – typically in conventional fixed-wing designs – to improve energy use, limit fuel consumption, and reduce emissions. Iturmendi was enthusiastic about hybrid projects: “This might be the category that has the easiest way toward certification.”

“Some people claim that you basically cut your fuel consumption in half,” Iturmendi said. “I have never worked on an electric-hybrid, but I am impressed with the results they’re getting compared to everybody else. It seems more realistic than the other categories.”

Energy Storage

One of the biggest obstacles to the practical application of electric aircraft is energy storage. The energy density of today’s batteries is dramatically less than that of jet fuel – around 250 watt-hours per kilogram, compared to 12,000 watt-hours per kilogram. Because of this, electric aircraft have shorter ranges and endurance, and smaller payload capacities than conventional aircraft. They also face challenges in less-than-ideal weather conditions. While today’s batteries have enabled researchers to develop a variety of short-range concepts, the industry is looking to emerging battery technology to help advance these projects.

“For better range on airplanes,” Iturmendi said, “you need batteries, realistically, that are in the 450 watt-hours per kilogram range.”

To address this need, researchers at the Massachusetts Institute of Technology (MIT) are developing a one-megawatt motor that, together with advances in battery technology, could propel larger future aircraft. The motor employs a powerful, compact, lightweight design in order to minimize the battery bulk that burdens existing electric aircraft. Already through the design phase, the MIT team has reported that the motor’s primary components can perform similarly to current small aircraft engines.

Anticipating the Future

As Iturmendi emphasized, certifying electric aircraft for commercial use may take some time. “It’s not as easy as just putting in an electric motor and flying.” Most electric aircraft lack a standardized path toward certification, but regulations from the FAA and EASA are underway. Iturmendi, on several committees himself, was optimistic: “New regulations are in progress within the FAA and EASA.” In this light, electric applications are a promising endeavor, waiting in the wings to support the industry’s effort to reduce its environmental impact and achieve net-zero carbon emissions by 2050.