The Soviet Union pioneered ground-effect flight with its “ekranoplan,” the Caspian Sea Monster first spotted by a U.S. spy satellite in 1967. Part boat, part plane, the hulking vessel, longer than a Boeing 747, rose to glide just above the water’s surface.
Watchful eyes on Narragansett Bay in Rhode Island may catch a glimpse of a 21st-century version undergoing testing: The Regent Viceroy Seaglider is a wing-in-ground (WIG) craft. In the aerodynamic phenomenon known as ground effect, proximity to that surface squeezes air beneath a craft’s wings to reduce drag and boost lift, with far less propulsive power required than for high-altitude flight.
The Rhode Island–based Regent Craft is, well, floating the Viceroy as a versatile, sustainable mobility solution for coastal passenger transport, defense, or cargo applications. Backers of electric WIGs view them as a more-practical alternative to eVTOLs, or electric vertical take-off and landing aircraft, which face major adoption barriers due to operational constraints and regulatory challenges.
The striking, 16.8-meter-long Viceroy took its maiden flight on 2 September, making it the largest-ever electric WIG to fly with people aboard. For that flight, soon followed by four others, the Viceroy flew a distance of 596 meters over 30 seconds near Regent’s headquarters on Narragansett Bay, with two captains aboard. Like similar “Type A” WIGs, the Viceroy’s preferred altitude is about half the length of its 19.8-meter wingspan, so 10 meters above the water. Much above that and a WIG can no longer exploit its aerodynamic edge, and loses stability.
Ground-Effect Flight for the Masses
The Viceroy is designed to “float, foil, or fly,” company executives say. It operates like a boat near docks, then rises onto a hydrofoil at higher speeds in preparation for takeoff. The craft is powered by a dozen electric motors and propellers mounted on composite wings. A roughly 500-kilowatt-hour battery pack below decks is equivalent to the packs of five Tesla Model S sedans.
Billy Thalheimer, the company’s 34-year-old chief executive and cofounder, says a similar “Tesla moment” is coming for aviation. “This will disrupt regional transportation, where you want to go fast,” Thalheimer says in an interview, “but you’re talking about routes that are too long to drive but too short to fly, because you’re sitting in the airport longer than you’re actually in the plane.”
Thalheimer, an MIT-trained aerospace engineer and aerobatic pilot, says his company sees an untapped travel market with big potential. “We’re going to focus on coastlines, by dusting off the technology called wing-into-ground effect,” says Thalheimer, who previously worked at Aurora Flight Sciences (a Boeing subsidiary), Blue Origin, and Virgin Galactic.
Think island-hopping—whether Hawaii, Nantucket, the Caribbean, or the Mediterranean—where airports may be small, overburdened, or nonexistent. Or traffic-clogged coastal routes that are the bane of drivers but that are also exorbitantly priced for flying: New York to the Hamptons is exhibit A. The company has raised more than US $340 million in funding from Lockheed Martin Ventures and other investors. Regent claims a $10-billion backlog of orders for its Seaglider, with commercial production set to begin at the end of 2027.
The Twenty Five, a luxury coastal-travel company, has an order for up to 60 Seagliders to cover routes on the East Coast, initially focused on the Northeast and Florida, in partnership with the maritime operator Hornblower.
Regent’s versatile vessel can fly at up to 290 kilometers per hour (180 miles per hour), roughly nine times the speed of a standard passenger ferry, with a 290-kilometer range. The Viceroy can carry 12 adult passengers and luggage in addition to its two captains, more than most private helicopters and small planes. Windows are generously sized, as is legroom. Maximum payload is claimed to be 1,588 kilograms (3,500 pounds), about 3.5 times that of, say, an Archer Midnight eVTOL, which, like most eVTOLs, is limited to four passengers.
Regent figures its unique flier has another advantage over eVTOLs. Under U.S. statutes and international maritime law, low-altitude WIG craft are currently classified as maritime vessels, not as aircraft, as are eVTOLs and seaplanes. Backers here say WIGs thereby fall under U.S Coast Guard regulation, not that of the FAA. That means WIGs appear poised to bypass the unresolved certification, airspace, and pilot-training issues that have left eVTOLs in a kind of regulatory limbo for the past several years. But the FAA’s new funding law does require the agency to collaborate with the Coast Guard over a two-year period, to hash out regulatory oversight of WIGs.
Unlike a plane cruising at 5,000 meters, the Viceroy can be operated by a certified master mariner, the highest grade of professional qualification for a ship’s deck officer, with some modest additional instruction. For comparison, licensed air pilots require relatively extensive and costly training.
Advanced Control Algorithms Make Flying a Breeze
At Regent’s 23,700-square-meter manufacturing plant in North Kingstown, R.I., I hop aboard a two-seat Viceroy simulator with wraparound video screens. Within seconds, I’m guiding the Viceroy’s deep-V-shaped hull through a simulated harbor off the coast of Maui, operating in its Float mode, in which its carbon-fiber hydrofoils are not yet extended. Outriggers at the tips of the wings act as floats to provide lateral stability.
Very sophisticated control algorithms mean that captains only need concern themselves with two main controls: A central lever manages speed, and a joystick turns (or banks) the Viceroy left or right. Pressing an onscreen switch unlocks near-autonomous transitions between four operating modes: Dock, Float, Foil, and Fly.
As I transition to Foil mode, the Viceroy lifts partially from the water, its outriggers rising above the simulated waves. Finally, it’s time for liftoff, and steady flight at about 10 meters over the surface. The transition from foiling to flight is the hardest bit, because a WIG is moving fast for a boat but extremely slow for an aircraft, at 60 to 84 km/h.
Soviet military versions were undone in part by hazardous liftoffs and tricky handling at low altitudes. Pilots had to make constant manual adjustments to avoid a catastrophic crash into waves. The original Soviet “KM” ekranoplan, in fact, crashed into the Caspian Sea in 1980, due to pilot error. No one was killed, but their sea monster sank about a week later. The collapse of the Soviet Union in 1991 marked the end of ekranoplans.
One breakthrough, Thalheimer says, is the Viceroy’s ability to hydrofoil as it approaches takeoff speed, reducing water drag and giving passengers a smoother transition to flight. Aircraft-grade redundancy includes multiple backups for electric power, computing, and connections to flaps and other control surfaces. Modern avionics, a virtual “Star Wars” fantasy in comparison with what was available during the Cold War era, automate virtually the entire process. On the simulator, I’m essentially a passive bystander as the Viceroy transitions autonomously from foiling to flying and back again. The Seaglider is designed to handle ocean swells up to a meter and a half high.
Once airborne, kilometers from shore, where coastal boat traffic becomes sparse, cameras and other sensors help spot slower vessels that would have the right of way at all times. That’s a good thing, because the Viceroy flies lower than the masts of larger sailboats and much lower than, say, the upper decks of a cruise ship.
Regent is also testing a smaller, uncrewed WIG, which it calls Squire Seaglider, backed by nearly $20 million in contracts from the U.S. Marine Corps Warfighting Laboratory and other investors. The Squire is being demonstrated for use in mobile communications with submarines or other vessels, as well as in medical and other applications.
Thalheimer points out another WIG advantage in safety, range and viability: Compared with higher-flying aircraft, the Viceroy doesn’t need to carry enough reserve fuel to make it to an emergency airport, or any airport at all. All it needs is water, wherever that may be.
“You’re always over your landing area,” Thalheimer notes.