Work is well underway to incorporate future eVTOL aircraft into military missions of all types.

“The military is still figuring out its exact use cases — ship to ship, ship to shore, and many others.” That’s according to Kevin Rustagi, director of business development at LIFT Aircraft, referring to the use of LIFT’s Hexa ultralight eVTOL and other eVTOLs that are yet to be certified with the Federal Aviation Administration. 

All those in the eVTOL sector already know, along with revolutionizing commercial transportation of people and cargo, disaster relief, some aspects of healthcare, etc., eVTOLs will also significantly change military and peacekeeping operations.

Indeed, the U.S. military has been taking a broad and deep look at eVTOLs for years now. Joby Aviation, Beta Technologies, Elroy Air and LIFT, for example, were all early participants in the U.S. Air Force AFWERX Agility Prime program and are still very much involved in various military research projects.

There are many obvious reasons why air forces, armies and navies are interested in eVTOL technology, but also some reasons not as apparent.

Off the top, there’s the ability to vertically take off and land, of course, and the way eVTOLs are powered by charging or by quick battery/fuel cell swap — no need to worry about the fuel logistics needed with helicopters and conventional aircraft. Then there’s the expected autonomous aspect, similar to the use of drones.

AFWERX spokesperson Ciska Bloemhard foresees that eVTOL tech will both “supplement legacy military platforms” but also provide “a hydrocarbon-independent alternative for missions like middle-mile logistics, personnel recovery and humanitarian aid.” Bloemhard added that with eVTOLs, the military hopes to reduce overall costs — both operational and maintenance — of various missions.

To this list of potential eVTOL benefits, those at Joby added increased speed of maintenance and significant improvements in reliability and acoustics compared to conventional aircraft like helicopters. In addition, a Joby spokesperson said “aircraft like ours are also able to take off immediately, rather than require minutes to spin up prior to takeoff.”

Leaders at Elroy Air — vice president of strategy and business development Kofi Asante, CEO Dave Merrill, and government business development director Karl Purdy — added efficient defense resupply to the list.

They said resupply is hardly optimized with traditional helicopters — particularly in combat scenarios, for example, because helicopter transport frameworks generally don’t involve enough people and aircraft to achieve the optimum on-demand tempo.

There’s already a shift, Elroy’s team said (and explained in documents like the U.S. Air Force Science and Technology Strategy), “toward larger numbers of lower-cost assets in the military, where each individual asset is attritable [or can be lost in battle].” This applies, of course, to drones, eVTOLs and other technology that can be operated remotely or autonomously.

Elroy leadership also pointed out that eVTOL technology better supports the concept of “places, not bases.” Simply put, eVTOL systems “enable a nimbler approach to staging people and materiel, where instead of establishing permanent bases that must be built and defended, the fighting force can pick up and move more readily, confusing an enemy who would like to destroy infrastructure to create advantage.”

Autonomous technology

The autonomous aspect of eVTOLs, Rustagi said, opens up many new use cases for military forces, including having many of them operate in tandem. Automated pickup/drop-off of payloads also means more cargo/personnel can be delivered within a given time period and greater overall operational efficiencies.

Asante, Merrill and Purdy at Elroy Air list increased risk tolerance as another benefit of autonomous technology. Uncrewed aircraft can take greater operational risks — flying resupply materiel into active fight zones and contested airspace, flying low to the ground, and so on.

Autonomous aircraft can also be operated continuously, regardless of the physical location of pilots or caps on working hours per day of pilots/remote pilots. There are also no pilot/cockpit requirements, reducing manufacturing costs, and for some applications like defense, a lower standard of certification may become acceptable, particularly for attritable air assets.

Ultralight benefits

Whether piloted or autonomous, ultralight eVTOLs offer other specific benefits for military applications.

The crewed version of LIFT’s Hexa ultralight eVTOL has been in tests in partnership with the U.S. military since 2018.

“The military likes that we were quick to get flying and test critical safety features,” Rustagi said. “We have done a lot of testing in partnership with both the University of Texas and the U.S. military through U.S. Air Force innovation research grants, alongside the Agility Prime program.”

He added that the Hexa’s configuration and ultralight design make it particularly attractive for military use. As an ultralight, the crewed version is already authorized for first response and recreational flights over populated areas, and both the crewed and cargo versions already have “military flight releases” to allow test flights at military bases.

Other military benefits of an eVTOL like the Hexa are the reduced level of complexity and maintenance, as well as the much greater safety they provide compared to helicopters, Rustagi said.

“Our aircraft has only 18 moving parts, [plus a joystick in the crewed version],” he explained. “With eVTOLs, you’re trading hardware risk for cybersecurity risk, but that’s why we have multiple redundancies. We have 18 independently-powered rotors, a triple-redundant flight computer — and we may add a fourth — and the ability to land and takeoff from water. We are also testing a whole-aircraft ballistic parachute in case of total motor loss.”

The military, he added, also likes the Hexa’s modular design and flexibility.

“Basically, below our rotor system, with its motors, propellers and batteries, the rest of the aircraft is essentially payload,” Rustagi reported. “We’ve already tested several cargo modules with remote flight capability. The cargo version can carry a payload of up to 350 to 400 pounds [160 to 180 kilograms].”

The Hexa is also suitable for rapid deployment, he said. The firm has been brainstorming with the military about launching from a large land vehicle, and there’s even a future possibility of dropping them from planes, each with a parachute that helps them safely reach an appropriate altitude and speed.

An eVTOL the size of the Hexa can also be charged anywhere there’s a way to generate electricity — for example, with foldable solar panels or a small wind turbine, technology it could carry onboard. No heavy-duty system is required to charge the Hexa’s batteries, just three regular outlets. LIFT is also working on extending the Hexa’s range with a fossil fuel-battery hybrid power system.

(Elroy’s Chaparral hybrid eVTOL — not an ultralight — also has a hybrid-electric powertrain. “The ability to refuel rather than recharge means that hybrid-electric eVTOLs can operate in a much wider set of operating locations, including those without electrical power infrastructure, which is very important to early military operations and austere locations,” Elroy’s team said.)

Some further updates

Designing for military markets is no different than other markets in that faster speeds, better reliability, more payload and longer range are always desirable. Refinements or new breakthroughs in these areas and more are sure to come in the years ahead. 

LIFT’s Hexa is expected to be commercially available sometime this year, which means military use will be officially possible at that point.

Elroy currently has three contracts with the U.S. Air Force, all with an autonomous focus. The contracts cover flight envelope expansion, rapid deployment, and hybrid powertrain development.

Joby, upon certification, plans to be ready to start on-base operations with the Department of Defense in 2024. Last year, Joby announced an expansion of its existing contract with the Agility Prime program that increased the contract’s potential value by more than US$45 million, bringing the potential value of the total contract to more than US$75 million. At the same time, the contract has also widened defense partnerships to include the U.S. Marine Corps, which is participating in government-directed flight tests and use case exploration.

Beta’s Alia-250 eVTOL is currently being assessed by the U.S. military for a variety of mission uses. “We’ve achieved several significant milestones with our partners at Agility Prime over the past few years, including the first crewed flight of an electric aircraft with both the Air Force and Army,” a Beta spokesperson said. “Those qualitative evaluation flights were the culmination of months of hard work and a weeklong training program inclusive of ground school academics and hands-on simulator training. In addition to these technical demonstrations, these partners have shared invaluable insight and expertise that helps us continue to develop our training tools and flight test programs significantly.” 

In addition, “our work with the Army continues to progress well … last year, they completed a crewed quality evaluation of our Alia-250 aircraft, making Maj. Wes Ogden the first Army aviator to fly in an electric aircraft and progress through our ground and simulator training programs. As well, we have had a number of senior Army leaders join us [at our company headquarters in] Burlington, [Vermont].”