The Incredible Stair-Climbing, Self-Parking, Amphibious Wheelchair

An Army vet’s quest to give paraplegics their life back
Brad Soden Photograph by Benjamin Rasmussen for Bloomberg Businessweek

On the morning of Jan. 6, 2007, U.S. Marine Corporal Joshua Hoffman and his platoon were notified of possible insurgent activity near their station in Fallujah, Iraq. When they arrived and began a sweep of an alley, Hoffman, a tall, strapping former wrestler with a passion for muscle cars, stood out. A sniper perched in a building behind him fired a single 7.62-millimeter round that tore through his neck, shattered his upper spine, and knocked him to the ground, paralyzed and unable to breathe. In the scramble to save him, a trachea tube inserted to prevent asphyxiation severed his vocal cords, depriving him, on top of everything else, of the ability to speak.

Hoffman’s rehabilitation was lengthy and grueling, both physically and psychologically. At one point he became so frustrated that he stopped communicating with his doctors and a parent had to assume power of attorney for him. “It was a really long road,” says his caretaker, Brenda Johncock. After two years in veterans hospitals, he returned home to Middleville, Mich., where volunteers built him a wheelchair-friendly home with an extrawide doorway to the garage and his Mustang. He could no longer drive it—any movement required help—but just going out to look at it made him happy.

One evening at a fireworks show, an American Legion member told him about an amazing contraption she’d seen: a modified wheelchair with tanklike treads that could climb stairs and ford a stream. A veterans group, the Independence Fund, was raising money to buy them for wounded soldiers and marines. Was he interested?

That’s how Hoffman came to know Brad Soden. Soden is the inventor of the Tankchair, which is a wheelchair in the same sense that an aircraft carrier is a boat. His fearsome-looking machine can traverse rugged hillsides, sandy beaches, snowy embankments, and, with a top speed approaching 30 miles per hour, keep up with traffic on a typical city street. Its brain is built by a company that designs Apache helicopter control systems, so the chair can elevate to a standing position or fully recline to aid blood flow. Some versions have gun mounts and fishing reels. Some have roll bars. A few glow in the dark. One chair Soden built for a paralyzed Phoenix police officer has a “vomit light” to neutralize suspects—a pulsing LED so powerfully incapacitating that it induces nausea. If Michael Bay had devoted himself to making medical equipment instead of action movies, this is what he would have built.

June 5 (Bloomberg) –- In 2005, Brad Soden invented a modified wheelchair for his wife Liz, who is paralyzed from the waist down, so she could actively participate in more activities with their family. These fearsome-looking machines can traverse rugged hillsides, sandy beaches and snowy embankments. Read more in Bloomberg Businessweek’s first Global Technology Issue, the definitive guide to the whole world of technology outside of Silicon Valley. (Source: Bloomberg)

As remarkable as the Tankchair is the man behind it. Soden is a robotics savant, with no formal training in engineering or even a college degree, who, like tech visionaries before him, invented a life-changing machine in his garage. But you’ll never catch him in a mock turtleneck rhapsodizing about the future. With his motorcycle boots, Hulk Hogan arms, and impish grin, he looks like a guy who crushes beer cans on his head. Only when he gets going about his latest creation does he sound like a creature of Silicon Valley: “How many times do you see a wheelchair so cool that people want to get in it?”

Last year he was demonstrating one in a Seattle park when Eddie Vedder of Pearl Jam wandered over to ask what it was. While Vedder went for a spin, Soden teased some teenage girls who were gawking at their idol by pretending to have no idea who Vedder was. Even without a rock star at the controls, it’s impossible to drive the chair in public without attracting crowds. Soden’s wife, Liz, has dubbed this “the prom queen effect” and counts it among the chair’s many virtues. “We’re taught as a society that it’s not polite to stare,” she says. “But people who get hurt don’t want to be shunned. Once they get in the chair, people will stop and come over.” And the conversations are all about what the injured person can do, rather than what he cannot.
Tankchair LLC is a family affair run out of a small industrial garage off a sunbaked strip of I-17 in North Phoenix. In addition to Brad and Liz, the company includes Jo-Ann Soden, Brad’s firecracker of a mom, Vic Soden, his taciturn dad, and Doofus, an excitable mutt who enjoys taking test rides. Together, the Sodens build, service, and deliver chairs to about 200 customers throughout the world. Although Tankchair is a business, the enterprise has the feel of a cause. Every chair is customized to the unique and demanding needs of the client, and behind every one is a story. Bill Weigt was a cop in Peoria, Ariz., forced to retire on medical disability after getting shot in the spine during a drug bust gone bad. Soden built him a chair painted like a police car, replete with flashing lights and guns. The city of Peoria balked at the guns but hired Weigt back as a police investigator when Soden grudgingly removed them (hence the vomit lights). Weigt delighted fellow officers at a police convention in Washington, D.C., last year by taking the chair on the road and pulling over cars with his siren and flashers.

Jenna Moore, a wisp of a girl, was dropped as an infant, causing a series of strokes and seizures. Her adoptive family lives in a hilly Northern California neighborhood inhospitable to most wheelchairs, so for much of her life, her parents and older brothers carried her. Soden built her a chair in Victoria’s Secret pink. Later, her mother called him, upset that Jenna had disappeared after an argument, as teenagers do. “Well, isn’t that a good thing?” he ventured. She thought it over and agreed that, yes, it probably was.

Gerald Brown, who lives in Denison, Texas, found Tankchair online and bought one for his son Joshua, an avid drummer afflicted with muscular dystrophy. Soden built him a chair he can control with his foot. It has a ventilator, ground effects lighting, and detachable snare drums. “Brother, it is just amazing what this man did for my little boy,” Brown says. Friday nights, Josh plays in the high school marching band, and he’s won state drumming competitions.

Since hooking up with the Independence Fund last year, Tankchair has focused almost exclusively on veterans, whom Soden often visits to take measurements and learn about their hobbies and passions. He also tries to deliver the chairs himself when he can, because there’s nothing like seeing someone do something he had never imagined being able to do again—playing on a football field with his son, going hunting, mowing the lawn. (Mower attachments are a Tankchair option.)

Last fall, Hoffman, the former marine, traveled to the Citadel in Charleston, S.C., for Lieutenant Dan Weekend, an event for wounded veterans run by Gary Sinise, the actor who portrayed an amputee Vietnam veteran by that name in Forrest Gump. Soden met Hoffman there to deliver his chair, which is controlled by a head array and has a ventilator on the back. “They got up early on Saturday morning and had a lesson,” says Johncock, Hoffman’s caretaker. “By lunch, Josh was doing doughnuts in the parking lot as Brad watched with tears in his eyes.” The chair included an additional feature, a Samsung Galaxy tablet with a Bluetooth speaker system. “He wanted to give Josh a voice again,” she says. The head array doubles as a mouse, so Hoffman can “speak” in an electronic voice. (“A way cooler one than Stephen Hawking’s,” Soden notes.) After six years of silence, Hoffman’s first phone call wasn’t to his parents but to a startled U.S. Navy buddy whom he gleefully told to “kiss my butt.”

Watching Soden dream up these features in his garage, one wonders whether the Tankchair will eventually resemble a Transformer robot. His latest innovation makes the chair appear almost sentient: a docking system that enables it to maneuver itself onto the bed of a pickup truck. To most people, the chair is a stunning piece of equipment. But to Soden it represents something much bigger and more important—an assault on the idea that a physical handicap, no matter how severe, should constrain a person’s ability to live the life he wishes to. At its heart, the story of the Tankchair isn’t really about technology. It’s a love story.
Brad met Liz in Parker, Ariz., a flyspeck two hours northwest of Phoenix. He’d grown up there, smart, restless, and bored. He liked to experiment. At 12, he was experimenting with accelerants when the wind picked up and three abandoned houses burned to the ground. After high school, he enlisted in the U.S. Army and wound up as a frontline grunt with the 7th Infantry’s mechanized division at the spearhead of the U.S. invasion of Iraq in the first Gulf War. The M1A1 Bradley Fighting Vehicle had just rolled off the line, and his unit was the first to receive it. He developed enough proficiency with the Bradley that when his vehicle threw off a track during battle, he climbed out in a minefield and changed it under fire. After the war he returned to Parker and became a plumber and volunteer firefighter.

Liz grew up in Los Angeles County, a city girl transplanted each summer to her grandmother’s house in Parker. She stuck around L.A. after high school to run an in-home day-care center. But she longed for something else. “What I really wanted to do was drive a school bus,” she says. She returned to Parker with her two young daughters, found the job she was looking for, got divorced, and settled in. Before long, she met Brad, who was also divorced and had three young sons of his own. They clicked.

“She was a city slicker until she met me,” he says. “I got her off the beaten path. She got to see a whole bunch of wildlife. Once you get off the sidewalk, the whole world opens up. To us a great date was a 12-pack of beer and some catfish down by the side of the river.” The kids liked camping, too, and the whole clan took to celebrating birthdays at Hualapai Mountain Park. Soden thought of them as the redneck Brady Bunch. “I was just going along,” he says, “happy as a clam.”

One day in 1999, Brad, Liz, and the boys were coasting down the highway in his truck when a tire separated. The truck swerved, flew off the road, and hit the side of a mountain. “I knew right afterward that she was hurt real bad,” he says. His fireman’s training taught him not to move her. With his own leg broken, he scooped up his sons, all younger than 3 and badly bloodied, and dragged himself back to the road to flag down help. When the fire and ambulance crews arrived, they extracted Liz from the wreckage and medevaced her to Las Vegas. One of the boys, whose jaw had been separated in the crash, was flown to Phoenix. He made a full recovery. Liz did not. When the truck hit the mountain, her legs absorbed the full impact. “Her spine basically went to powder,” Soden says. She suffered an L1 burst fracture and was paralyzed from the waist down.

When families experience devastating injuries, they often try as much as they can to keep life as it was before. Brad and Liz were no different. She missed the outdoors. When she was finally able, in 2003, the family headed back up into the mountains. Early one morning, Soden awoke and saw a herd of elk passing through the campground. “C’mon,” he called to his sleeping family, “let’s go follow them.” Kids spilled out of the cabin, Liz climbed into her wheelchair, and the family crept quietly down the path after the elk. But Liz couldn’t keep up. Her chair kept getting stuck. “She’s the most unselfish person you’ll ever meet,” Soden says. “So she said, ‘Just go on without me.’ ” Then she sat there and cried.

“It just tore me up,” he says. “I didn’t want her being stuck anymore, not anywhere. I resolved to make her something. If we go out camping and she wants to come, dammit, she’s gonna be able to come. That’s when I started.”
Within days of that trip, Soden disappeared into the garage and started experimenting again. He began with accelerants. From an engineering perspective, the main challenge to building an off-road wheelchair is generating sufficient horsepower. He tried modifying diesel and lawn mower engines, eventually building a prototype from a hand-powered 250cc gas engine of the type used in dune buggies. This had several drawbacks: It was noisy and dirty and couldn’t be used indoors or even, he discovered, in national parks. It had no suspension, so it was murder on the back. Also the cost of insurance was prohibitive, because, as he puts it, “you’re putting a combustible material under the butt of someone who can’t get up.”

He switched to electric motors. When a plumbing customer couldn’t pay for a big job, Soden accepted a 1966 Harley-Davidson golf cart as payment. He rebuilt the cart from the tires up, installing a hand controller and giving it a gleaming coat of paint. He had proposed to Liz, and they were going to be married in the desert. “She didn’t want her wheelchair in any of the wedding pictures,” he says. Instead, she rode out to the altar in the modified Harley and was given away by her grandfather, an old cowboy, as her little girls in their lace dresses beamed from the back seat. “After the judge married us,” Soden says, “we put the boys on, symbolically joining the family, then drove off through the riverbed and celebrated with pit meat and beer.”

By now it was clear that electric motors were the way to go. But Soden kept getting stuck on another engineering challenge: generating enough friction so the wheelchair wouldn’t get stuck when it left the blacktop. It needed a bigger footprint and more low-end torque. This led to wild-looking machines with giant racing tires. But the voltage necessary to turn the wheels produced so much heat that the chair’s wiring would melt. Engineers Soden consulted advised him to give up. “They kept saying, ‘According to the laws of physics, what you’re trying to do will not work,’ ” he says, laughing. “Well, according to the law of physics, bumblebees and helicopters aren’t supposed to fly, but somehow they get off the ground.”

The problem did seem insurmountable: Any wheel fat enough to grip sand, snow, and mud required more power than an electric motor small enough for a wheelchair could supply. The breakthrough came one day in the garage with Liz’s dad, Barry. “We were just sitting out there,” Soden says, “and he says to me, ‘Man, you know what’d be cool? If we could put tracks on it, like a tank.’ ” Soden felt as if he’d been hit by lightning. “That’s when I knew exactly what it was going to be,” he says. “It made so much sense.” He found a company called Mattracks that makes rubber tank treads.

The final challenge was adapting the treads to a wheelchair. Most vehicles that run on treads, such as snowmobiles, don’t execute sharp turns. But wheelchairs need to make zero-point turns—that is, turn in place. Bradley Fighting Vehicles can do this because their treads operate independently through a skid-steering system that requires great skill to operate. Power wheelchairs use a simple joystick. The solution presented itself late one night on cable TV when Soden was watching BattleBots, a short-lived science show on Comedy Central in which contestants built remote-controlled robots armed with weapons such as circular saw blades that battled each other, gladiator-style, to the death. Some of the BattleBots were treaded and pivoting on a dime. He tracked down their creator, who lived in Minnesota and loved the idea of a life-size BattleBot for transporting humans. They talked through the technical challenge for hours, without any luck. Finally, Soden loaded the chair onto his pickup and drove straight through to Minnesota. Within an hour of his arrival, they had found a solution. They hacked the module’s safety protocols to trick it into letting them operate the right and left motors independently, as a Bradley does.

Soden returned home and took off with his family for the Kaibab National Forest on the north rim of the Grand Canyon. A picture from that day of Liz in the chair hangs on the office wall. He says, “She went off for a hike with her daughters for the first time since the accident with just a big ol’ grin on her face.”
The original Tankchair still sits in the corner of the Sodens’ garage. It’s made with tin cut from an air-conditioning unit, an audio fuse from a car stereo system, and rubber treads from an ATV. Toilet bowl bolts fasten down the seat, which holds a flat cardboard box with big eyeholes cut out. In 2005 a producer at Pixar saw a video of the chair online and invited the family to the studio’s headquarters in Emeryville, Calif. That’s how Soden found himself, a few weeks later, rolling around in the chair with the cardboard box on his head—the human inspiration for the trash-collecting robot in Pixar’s 2008 animated film, WALL-E. “They put a s-‍-‍- ton of cameras and sound equipment out there and filmed me a bunch of times running over trash,” he recalls. (You can see this yourself in the DVD bonus material.)

Soden never stopped experimenting, steadily improving the chairs’ quality and production efficiency. Early models cost $22,000 to manufacture and took four weeks to complete; today, he can make as many as 10 a week at $15,000 each. Recently he switched from using wet-lead batteries (like those used in conventional cars) to cutting-edge lithium ion polymer batteries, or LiPos. These provide 50 percent more power than wet-lead and last 15 years, instead of the two or three he was getting before. Without ever advertising, Soden began selling chairs to people referred by friends or who found him online. In 2008 he quit plumbing to build chairs full time. To keep up with orders, he recently moved to a bigger facility.

A couple of things stand in the way of broader success. One is the government. The market for wheelchairs is shaped almost entirely by what Medicare will reimburse, because the federal government, which spends about $1 billion a year on power wheelchairs, is by far the largest customer. The industry is a textbook example of regulatory capture. Getting certified by the Food and Drug Administration—a condition for federal reimbursement—can easily cost $1 million, making it all but impossible for small innovators to reach the largest markets. So Tankchairs are classified as recreational vehicles, which insurance plans won’t cover. “There’s a lot of stupidity in the bureaucracy,” Soden says. Worse still, the big medical-equipment makers inflate their prices enormously. A 2011 report by the U.S. Department of Health and Human Services Office of Inspector General found that Medicare pays 400 percent of what it costs suppliers to make a power chair and that 80 percent of those payments are made in error, because the industry routinely pressures doctors to prescribe chairs to patients who don’t need them, costing taxpayers hundreds of millions of dollars each year.

Liz and Brad
Photograph by Benjamin Rasmussen for Bloomberg Businessweek

Soden, on the other hand, is a compulsive savior, which, in a strict moneymaking sense, is an obstacle. In May he drives out to the desert to visit one of his first customers, Jean Hamman, 57. A recent widow, she affectionately calls her Tankchair “Sherman” and uses it to care for her miniature horses, whom she has named after Harry Potter characters. Soden was eager for her to try out his latest model, which is smaller and sleeker than Sherman and, it turns out, allows easier access to the horse pens. “Cool deal, Brad!” she practically squeals. “Now I can mulch the horse s-‍-‍-!” By the time he leaves, he’s repaired her broken Medicare chair and promised to give her a new Tankchair. It’s clear that these gifts, and his insistence on selling the chairs he builds for veterans at cost, leave his finances in a more precarious state than they should be; but he says he carries no debt and would welcome the right partner.

His business is helped along by a large network of friends, supporters, and companies eager to see him succeed. Corbeau, a maker of race-car seats, supplies its product at a discount. U-Haul provides trucks at no charge to deliver the chairs to veterans. La Quinta hotels let the drivers stay for free. A group of NFL Hall of Famers whom Soden met at a golf tournament is raising money to buy chairs that will be given away at next year’s Super Bowl in Glendale, Ariz. “There are people who appreciate our way of life,” Soden says, “and appreciate those who have given all you can ask and then some.”

A few weeks ago, the Sodens set up American Heroes Transportation, a moving company to employ vets that has begun delivering chairs around the country. They’re also planning to build a small factory near Lake Havasu that, along with building chairs and doing other light manufacturing, will function as a technical school for disabled vets. “A while back,” Soden says, “I met a soldier in California, a triple amputee, who was taking care of his baby. One thing he said that stuck with me was, ‘I wish I could go back to work again.’ ”

Here again, government policy poses an obstacle, because even blind or paralyzed veterans risk losing their Social Security disability benefits if they earn too much income. Sergeant Major Jesse Acosta, a board member of the Independence Fund blinded by an improvised explosive device in Iraq, discovered this the hard way when he found work as a supervisor at Southern California Gas. Although he reported the job to the Social Security Administration, the agency continued sending him benefit checks until last year—when it turned around and sued him to recoup $80,000. “It’s a moral travesty that you jeopardize the compensation of these men and women just by employing them,” Acosta says. “We should be doing all we can to get them off the couch, but the government just wants to keep them there.”

The recent scandal surrounding the mistreatment of patients at a Phoenix veterans hospital—a problem that now appears to be widespread throughout the country—has only deepened Soden’s determination to find more ways to help veterans. “I’m gonna give them a job,” he says. “Not just a gardener job, but a trade, so that once they walk out of my shop, they’ll know how to machine, how to tool, how to laser cut. They’ll be employable, and people will want to hire them. This triple amputee guy, I’m gonna make him a rig for his missing arm—like the Terminator. We’re going to make it in the shop; it’ll be his when he goes. There’s a lot that a job cures. One thing he told me was, ‘I love being with my kids, but I miss bringing home the bacon.’ I said, ‘No problem, man, we’ll do it.’ ”