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Lundi, 21 Mars 2011 12:00

One Man's Quest to Outrace Wind

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Rick Cavallaro, a hardware and software engineer, ignited an online flame war with his proposal for a Rube Goldberg wind-powered vehicle.
Photo: Lucas Foglia

The Mojave Desert’s dry Ivanpah lake bed shimmers under a vicious solar glare,creating the illusion of water. Piercing the mirage are dozens of sails—a vast array of color streaking over a dusty ocean. It’s the last week in March, and Ivanpah is hosting the North American Land Sailing Association’s annual dirt-boat championships, the America’s Cup. It may seem odd to give this competition the same name as the more famous ocean race, but truth be told, in a strictly technical sense the two America’s Cups are quite similar. Dirt sailing is sailing, after all: The tactics are the same; the maneuvers are the same. The main difference, as people who race on dirt are keen to point out, is speed. Sailing on a dry lake is about three times faster than sailing on water.

Then there are the competitors themselves. “There’s just something about the desert that attracts strange people,” longtime dirt sailor Richard Jenkins says. He would know: Jenkins is the current king of the Dirt Cup, as some call it, having set the world speed record at the competition in 2009, when his land yacht, Greenbird, hit 126.2 miles per hour. “Land sailors are a weird bunch. Oddballs. Alternative in every respect.”

Cavallaro knew that a sail on a tack and a spinning propeller blade were aerodynamically the same.

No one here is weirder or more alternative than a mustachioed man who has shown up this year with an exceptionally strange-looking dirt boat and an extraordinary claim. The man, a fast-talking inventor named Rick Cavallaro, says that his craft—Blackbird—can, while sailing directly downwind, go faster than the wind that is propelling it.

Jenkins, like other veterans of the Dirt Cup, thinks this is preposterous. There’s no doubt that a boat (dirt or otherwise) can go faster than the wind. That’s part of the magic of sailing: By running at an angle to take advantage of crosswind effects, a boat can outpace wind speed. But directly downwind? Impossible. In a best-case scenario, a sailing vessel headed directly downwind will move at the speed of the breeze that’s pushing it.

The problem with downwind sailing is that from the perspective of the craft, once it reaches wind speed there is no more wind. And if there is one thing every sailor knows, it’s that “you can’t power through zero wind,” as Jenkins says. Not only would the sailing craft have to somehow pull ahead of the wind that’s pushing it, but from the perspective of the sailors on board, it would face what feels like a headwind pushing it back. In sailing, zero wind—real or apparent—is considered an absolute barrier, like the speed of light in physics.

Yet Cavallaro claims that Blackbird can break this barrier. Not only that, he says, it will likely go downwind twice as fast as the wind. The boast is made all the more outlandish by the fact that Blackbird doesn’t have anything that looks even remotely like a sail.

The craft is a crude contraption of plywood, carbon fiber, bicycle parts, and pieces of go-cart. It’s low and relatively streamlined, except for the 14-foot-high tower mounted behind the cockpit. Attached to this is what can be called—for the sake of argument—Blackbird’s sail. Many will choose to call it a giant propeller, because it has two diametrically opposed 8-foot-long blades that rotate just like, well, a giant propeller. But propellers imply motors. Blackbird’s rotating propeller-shaped sail is the motor. Cavallaro has connected the prop to wheels via a drivetrain, so the faster the cart rolls, the faster the sail-prop spins, thereby creating a feedback loop that Cavallaro claims will accelerate the cart from a standstill through the zero-wind barrier and beyond.

To most people, Blackbird’s engineless drivetrain sounds like a perpetual-motion machine. “Cartoon physics” was typical of the barbs thrown at Cavallaro when he revealed his idea. But he remained undaunted. Blackbird is the result of a years-long quest—a personal attempt to prove something deeply counterintuitive to the world. A software and hardware developer with a degree in aerospace engineering, Cavallaro has done the math. He has made small models and run tests. His contraption will work, he says. Even if no one believes him, he is certain that he’s right.

But any sailor worth his salt—or dust, as the case may be—will tell you he’s wrong. So will many engineers and physicists. And they’re not shy about spelling it out. Since Cavallaro first proposed Blackbird’s design on the Internet, his concept has been ridiculed and lampooned in blogs and forums, and the idea has even been refuted in a national magazine. The debate recently reached a fever pitch among a certain type of geek, especially in Silicon Valley, so much so that some notable entrepreneurs, including Google’s Larry Page, forked over the cash to let Cavallaro finally build the vehicle. After four years of online arguments, explanations, and insults, Cavallaro has brought his vision here—to the Dirt Cup—to prove he can beat the wind.

This is where the Rube Goldberg rubber hits the hard, flat playa. Cavallaro is suited up in a helmet, goggles, and motorcycle pads. Now all he has to do is make the damn thing work.

He climbs into Blackbird’s coffinlike cockpit. His seat is just a hammock that hangs a few inches above the ground. A single front wheel from a BMX bike rests between his feet. There is a rudder in his right hand and a brake under his left foot. Every instrument—every GPS device, every anemometer, every radio—is double-checked to make sure Blackbird’s speed will be recorded accurately. The ground crew triple-checks that the craft is pointed directly downwind. When Blackbird is finally ready to roll, Cavallaro pops open the brake.

And nothing happens.

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