Here's a riddle: What isn't a boat, isn't an airplane, isn't a car or a truck, though when you drive it, you feel like you're flying and that you're traveling through water?

The answer: an air-cushioned vehicle, more popularly known as a hovercraft. It looks like a cross between a smallish boat and a space ship for two, and it rides on a cushion of air.

Now one Iowa company says the time is right to bring the vehicle to the mass market. The hovercraft as novelty has long been popular in England and other parts of Western Europe, but has never particularly caught on in America. Nonetheless, many companies offer build-your-own hovercraft plans, claiming that even a schoolchild can assemble one. And the 17-year-old Hovercraft Museum in Lee-on-the-Solent, England, houses a compendium of hovercraft plans and a variety of the craft themselves.

And hovercraft enthusiasts across America, Europe, and Australia have all formed clubs to discuss and to keep alive the spirit of their favorite invention. Perhaps one of the vehicle's appeals is its appearance: straight 1950s sci-fi. Indeed, a 1959 issue of Popular Science proudly boasted a hovercraft on its cover.

But it's time to take the air-cushioned vehicle from the realm of scientific marvel into that of utilitarian workhorse, says William Kirby, chief executive officer of Gimbal Craft in Fairfield, Iowa. He claims that, while thousands of boats were sold in the U.S. market during 2003, only a few dozen diehard fans purchased hovercraft.

"They give you a sense of flying," Kirby said. "You're not in a boat riding on the water, but you're not in a wheeled vehicle riding over the land."

A hovercraft maker wants to bring these vehicles to the masses.

Hovercraft generally rise a few inches to a few feet in the air and are propelled forward, bobbing on the air cushion. They work best on flat surfaces, which is why they're generally used on water, Kirby said. They can mount rises of about two feet but don't travel well over some surfaces, performing best over water, ice, and snow.

"They're not hill climbers," Kirby said.

The vehicles never caught on because they lack controllability, he added. Wind can interfere with the air cushion. But Kirby thinks that his company can surmount the controllability issue with the help of Gimbal fan technology. William Bertelson, a medical doctor with engineering experience who has been working the past 50 years to perfect hovercraft technology, invented the fan. Gimbal Craft licensed the technology.

Bertelson says the dismal picture of today's polluted, gridlocked cities, where transportation is more and more difficult, need not be a reality. And hovercraft are the way to surmount the problem.

In 2002, Bertelson, of Rock Island, Ill., was awarded the title "Father of the Air-Cushion Vehicle" by the World Hovercraft Federation.

His fan technology controls the flow of air in a way that gives the pilot—or, if you prefer, driver—control over the direction of the vehicle to a greater degree than past air-cushioned vehicle drivers had. The fans operate within a cylindrical tube.

If they are mass-marketed, these air-cushioned vehicles could be used for search-and-rescue missions because they can access remote, weedy, or low-lying, water-filled areas that other types of vehicles can't get to, Kirby said. Although they can run at about 50 miles per hour over water or land, they give off fewer emissions than boats or cars because they use less power. And they don't churn the water with a blade the way boats do, he added, which means they could move quickly through no-wake areas where boats aren't allowed to pick up speed.

The craft can also be used within environmentally sensitive areas like wetlands, because they ride above the surface and don't dig into it. For homeland security purposes, they can access remote areas, and they would be particularly helpful in navigating rivers.

"They're truly amphibious," Kirby said. "They probably won't replace cars, because they do kick up dust. You wouldn't take them out in a hurricane or a blizzard. But in places where the rivers freeze up, you could just commute to work on the waterway."

home | features | weekly news | marketplace | departments | about ME | back issues | ASME | site search

© 2004 by The American Society of Mechanical Engineers