Rick Cavallaro had never considered whether it would be possible for a sailboat to outrace a balloon traveling directly downwind in the same direction, but when a friend posed the query to him one afternoon in 2000, he said he’d think about it.
It was an unlikely question, but Cavallaro—an engineer by trade and a daredevil by nature—is always up for a brain-bending challenge.
He walked through the scenario’s obvious factors: If the sailboat and the balloon both were powered exclusively by the wind, both traveling directly downwind in the same direction, they could only ever go as fast as the wind is blowing, the laws of conservation being what they are.
The sailboat could go faster than the balloon by tacking in a zig-zag pattern in the general direction of the end point, catching the cross-wind, but that would violate the “directly downwind” part of the question—the trickiest part, the fun part. Meanwhile, the balloon, taking the slower but straighter route, would still beat the sailboat every time.
So the obvious answer was “No.”
But Rick Cavallaro is not a fan of obvious answers.
*
Rick Cavallaro is 51 years old, but he still eats strawberry Pop-Tarts for breakfast every morning. He orders them by the case from Amazon and keeps his Mountain View, Calif., apartment stocked at all times. There are a few restaurants he likes in town—the Mexican place, the Thai place—and when the servers see him walk through the door, they already know his order. He’s lived in the same apartment since 1989; he knows what he likes, and he likes it here. No need to reinvent the happily turning wheel of his life just for the sake of something new. He takes his risks elsewhere.
When he was a kid it was skateboarding, driving fast cars, flying Cessnas; these days it’s paragliding, kite-surfing, sky-diving and especially snowboarding. He likes to run moguls, and he really likes to veer off the main slope and head into the woods, weave between the trees, make his own path. His brother has two rules for family ski trips. Rule one: Don’t follow Rick into the woods. Rule two: If Rick says, “No, really—it’s great, the trees are spaced pretty wide, come check it out,” refer back to rule one.
Such caution isn’t unwarranted. Cavallaro has crashed a few times off-slope, once bonking his head so hard he spent the next few hours back at the lodge in the throes of hallucinations. These days he wears a helmet, its dome bearing more than a few gashes and scrapes, ill-gotten souvenirs from encounters with low-hanging branches.
On the slopes and in his work, Cavallaro is a thrill-seeker. But it’s not just the promise of cathartic brushes with danger that pulls him into uncharted territory. It’s the knowledge that taking risks—and getting a little roughed up in the process—is pretty much the only way to accomplish anything remarkable.
*
Rick Cavallaro knew it was supposed to be impossible for a vehicle powered by the wind to travel directly downwind faster than the wind, but what if it wasn’t?
Maybe it couldn’t happen on Earth, he thought, but what about another planet—say, a cylindrical one covered entirely by water, where the wind blew long-ways from one end to the other? He thought about the sailboat racing the balloon again, but on that other planet: The balloon would move through the air just like it would on Earth, but the sailboat could catch an endless cross-wind—not by tacking back and forth, like its earthly counterpart, but by sailing in a spiral around the circumference of the long cylinder.
Next, Cavallaro wondered: How could this scenario be made to play out on Earth? Well, what here looks like a sailboat spinning down the length of a cylindrical planet? Tweak the scale and you’ve got yourself a propeller blade moving around a threaded rod. Attach that propeller to the back of a cart, gear it to the wheels, let the wind push the cart; the wheels turn the propeller, the thrust generated pushes the cart forward faster, which causes the wheels and the propeller to turn faster still. What do you get? A wind-sparked, feedback-loop powered … thing.
A thing capable of traveling directly downwind faster than the wind.
A thing capable of the impossible.
*
Rick Cavallaro is really good at being wrong, but that hasn’t always been the case. For many years, his ability to be wrong was only slightly above average. In high school in Naples, Fla., and later at Georgia Tech, he was the typical brainy slacker. He has a few embarrassing memories of challenging his professors during lectures, insisting that their points were incorrect or impossible—memories that sting because, even back then, he prized his ability to recognize and admit his wrongness, to avoid the trap of the Dunning-Kruger effect, that pesky tendency of humans to feel more confident about a subject the less they actually know about it.
Flashes of academic overconfidence aside, at Tech Cavallaro came to see critical thinking and problem solving as their own disciplines, things that could be taught and learned and practiced. He became especially enamored with word problems—solving them methodically, always working backward, parsing out every bit of information needed to reach the end result.
In his aerospace engineering classes, Cavallaro also grew to admire counterintuitive solutions to complex conundrums—Gordian-knot type situations, problems better solved by pulling out a knife and slicing through rather than picking apart tedious tangles just to maintain the status quo. When he found himself struggling in a history course because there were no basic formulas to guide his studies, he tried to learn self-hypnosis to trick his brain into latching onto all the discordant facts of the world. It didn’t exactly work, but he learned the benefit of approaching problems with a certain open-minded skepticism.
And as his respect grew for the scientific laws of the universe—the laws of conservation, of thermodynamics—he felt less and less attached to the rules of received wisdom and so-called common sense. He came to believe that the world is made of two kinds of people: those who, after the apocalypse, would still stop for a red light, and those who would drive on through, unencumbered by what was “supposed” to be. He decided he would be one to drive on through.
*
Rick Cavallaro had dissected the problem of the sailboat and the balloon for his own obsessive enjoyment, but his propeller-spun conclusion seemed worth sharing with the world. And so, around 2001, he turned to the internet messageboards for hobbyist kite-surfers that he frequented and posted a friendly brainteaser: Could a wind-powered craft travel directly downwind faster than the wind? The response was a resounding “of course not,” but he pressed on, posting his calculations, going back and forth with other message-board users, hashing out and clarifying his data. Unbelieving readers called him moron, a huckster, a hack—but he knew he was right.
General debate and balking continued apace for several years. In 2006, one especially vocal skeptic, a fellow hobbyist named Mark Conroy, gave in and built a model based on Cavallaro’s rough plans. He tested it at home and posted his results: The model did not work; it could not go faster than the wind.
But Rick Cavallaro, being Rick Cavallaro, pushed on ahead. He knew Conroy’s failed attempt didn’t prove that his idea didn’t work, only that it hadn’t worked yet. So he and John Borton, a coworker and toy helicopter enthusiast, built a model of their own, carved the propeller themselves, set the craft up on a moving treadmill in a room with otherwise still air. And that one worked—but just barely. They posted their results and a video online, and were startled to hear back within 48 hours from Conroy, who had tested an even simpler version of the cart built from model helicopter and airplane parts. This time, before his skeptical eyes, it had worked—not only better than his first test model, but better than anything Cavallaro and Borton had built so far. And so Cavallaro’s most committed doubter was converted, a new believer. But what about the others? On the messageboards, doubts didn’t just linger—the virtual air was thick with them. A tabletop model was not enough. If Cavallaro had any hope of disproving his nay-sayers, he would have to go big.
*
Rick Cavallaro graduated from Tech in 1984 with a notion of how to think about the world but no clear idea of how to make his way in it. He moved to California and kicked off a string of jobs that taught him, slowly but surely, that every little failure is an opportunity to learn something, move on and do better next time.
First came the Aerospace Corporation, a private nonprofit servicing the aerospace and defense industries. There, in the waning days of the Cold War, he ran simulations on how the U.S. might best respond to a launch of Russian nuclear missiles—a day-in, day-out meditation on the end of the world. (Lesson learned: Despite having no philosophical problem with the work, he also had no constitution for it.) Later, at a firm named Failure Analysis Associates, he ran simulations for legally embroiled manufacturers to prove the ways their product couldn’t have led to the accidents or injuries or deaths for which they were being sued. (Lesson learned: He was interested in problem-solving, not blame-absolving.)
All the while, he kept a figurative knife close at hand, cutting through any Gordion tangle that fell at his feet.
In the meantime, he earned a master’s degree in dynamics and control theory from UCLA and kept at a problem he’d been working on since his first day at Aerospace, where he’d seen a female coworker walking down the office hallway and a flash in his brain told him, “That’s the woman you’re going to marry.” He approached the situation like a word problem on a Tech exam, working backward from the desired end result. What needed to happen? What did he need to do to make that happen? Step one: Talk to her. Step two: Ask her out. He did; she accepted. Seven years later, they got hitched. Now, his wife joins him on ski trips. She won’t follow him into the woods, either.
*
Rick Cavallaro knew his calculations about the downwind craft were correct, but John Borton insisted the world needed more concrete proof. So they decided to go all the way: They’d build a full-scale manned vehicle, test it before a crowd and have the results verified by an independent judge.
They mined some Silicon Valley contacts for help—Google and Joby Energy both signed on as sponsors—and in late 2009 found themselves with budget enough to fund the construction of a full-sized land-boat: 23 feet tall, 450 pounds, the propeller 17 feet tip to tip. The finished craft was a mish-mash of plywood, carbon fiber, bits of bicycles and go-kart parts—not exactly elegant, but it would work. Or so they hoped.
They named it “the Blackbird.”
*
Rick Cavallaro never much cared for hockey, but in 1996 it changed his life.
After leaving Failure Analysis Associates, he was hired by Etak, an early pioneer of in-vehicle navigation systems. The company was sold to Rupert Murdoch’s News Corp. around the time Cavallaro joined the team as a developer, and a few years into his tenure he was scooped up to develop a system to track on-ice movement of hockey pucks for broadcast TV. While the technology, dubbed FoxTrax, was still in development, Fox staged a marketing campaign claiming they were preparing to introduce the most revolutionary advancement in broadcast sports since the instant replay. After almost a year of testing and re-testing, Cavallaro and his team arrived in Boston, where the FoxTrax would debut during the 1996 NHL All-Star Game, only to find that their hotly-anticipated system—which relied upon a delicate interlinking of infrared sensors and cameras—was in danger of being rendered invisible by an unexpected glut of pyrotechnics and banners hanging from the arena rafters. On one test run, their system could barely even track the Zamboni.
It was a precarious three periods, with a new potential for failure every time a new puck (each cut open by hand and fitted with infrared LED lights) was dropped onto the ice. But it worked. The game was the highest-rated hockey match of all time, and Fox retained the software for the three years they held NHL broadcast rights.
FoxTrax was a major breakthrough for entertainment technology and for Cavallaro’s career. But there’s no end point to innovation, and past success is no guarantee against future failure.
Emboldened by the success of FoxTrax, Cavallaro and the team spun off into the independent SportVision in January 1998 and immediately set upon what seemed like the next sports broadcast game-changer: AIRf/x, an on-screen measurement of basketball players’ jump height. Rather than revolutionize the sport, though, AIRf/x served to illuminate an unexpected but seemingly immutable detail. As it turns out, most basketball players jump the same height every time—right around 19 inches. Broadcasters couldn’t get excited about the product because they knew audiences wouldn’t get excited. AIRf/x worked in that it was competently executed, but there was no mystery to unlock, nothing unseen to illustrate, no story to tell.
But here’s another thing about innovation: In the process of taking risks, in pushing yourself and your work out of bounds, you’re going to fail once in a while. But if, like Cavallaro, you can admit your failure and think of your wrongness as a chance to learn and correct course, then you’re always getting better, always moving forward. If you’ve got the vision, there’s no shortage of next opportunities to prove it, or improve it.
Sure enough, after the AIRf/x no-go, SportVision bounced back with the Virtual Yellow 1st & Ten graphics system, a digital indicator of the first-down position for at-home football viewers. Revolutionary when it debuted in 1998, it’s now as commonplace in broadcast games as cheerleaders on the sidelines. That breakthrough was followed in 2006 by PITCHf/x, a system measuring the speed and trajectories of pitched baseballs, now installed in every MLB stadium. But for Cavallaro—by then a senior vice president of operations, at long last settled into his niche—his biggest ever opportunity to be very right, or very wrong, was still lurking just over the horizon.
*

HOW IT WORKS: The Blackbird confounded skeptics in part due to its deceptively simple design. One common misconception is that the cart’s movement is initially sparked by the wind turning its propeller. But, Cavallaro explains, the wind hits the cart and pushes it forward as one “bluff body”; the propeller, geared to the cart’s wheels, only begins to turn once the cart begins to move. The propeller then generates thrust, which pushes the cart forward at an increasing speed. And that’s when things get interesting. “Unlike a sailboat going directly downwind, the cart is not exploiting the wind relative to itself,” Cavallaro says. “Instead, it’s designed to exploit the wind relative to the ground, which continues to be an available energy source even when the cart is at exactly wind speed.” The top speed is determined by the cart’s gearing, of course—but until it hits that point, it’s locked in a feedback loop: the faster the cart moves, the faster the propeller turns, the more thrust is created, the faster the cart moves. And that’s how you go directly downwind faster than the wind. (Click image to expand.)
Rick Cavallaro had already figuratively poured himself into the Blackbird, but when it came time to test the craft in early 2010, he literally fitted himself into the vehicle. Its parts were the same as the tabletop test models just bigger, the design now including a just-barely man-sized sling into which Cavallaro situated his body, a bit like a luger, in order to steer and brake the craft and control the variable pitch propeller.
That March, Cavallaro and Borton took the Blackbird to the Mojave desert’s vast Ivanpah lakebed, home of the annual North American Land Sailing Association’s America’s Cup race, a site already vetted for the performance of dirt-boats and land-yachts. As Cavallaro strapped himself in for the day’s first run, he figured they’d need a few tries to get the gear ratios and prop pitches just right. With a small crowd watching at a distance, he settled into the Blackbird’s sling, released the hand-break and waited. The wind was blowing right around 15 miles per hour that day, cutting clear across the bare lakebed, hitting nothing but the gathered onlookers and the strange Frankenstein’s monster of a land craft.
For a few moments, all was still. But then, without a nudge or a spark, powered at first by nothing but the wind, the Blackbird began to move.
Slowly, at first, and then less and less slowly.
The wind pushed the cart, the moving wheels turned the drive train, the drive train spun the propeller, creating thrust that pushed the cart forward, igniting a feedback loop—just like Cavallaro knew would happen. The faster the wheels turned, the faster the propeller turned, the more thrust was created, the faster the wheels turned. Orange telltales tied to the craft whipped forward in the wind as if reaching into the future.
As the Blackbird moved faster and faster across the desiccated lakebed, away from the cluster of boggled spectators. Cavallaro called the stats out over the radio—9 then 11 then 13 miles per hour. And then the Blackbird hit 15—the speed of the wind.
The orange telltales fell limp for a moment, then fluttered back up—but in the opposite direction, now trailing behind the Blackbird as it sped along. The craft had hit wind-speed and kept on going, from 15 to 17 to 19 and faster and faster still.
Cavallaro eventually pulled the brakes at around 30 miles per hour—twice the speed of the wind.
That day out on the Ivanpah lakebed, Rick Cavallaro did the impossible. And a few weeks later, he did it again. After some repairs and upgrades, in July 2010 Cavallaro and Borton took to a dry lake bed in El Mirage, Calif., to demonstrate the Blackbird for officials from NALSA. Again, they hit wind speed then blew right past it. The organization now considers the Blackbird the first successful attempt on record to sail directly downwind faster than the wind. Not long after, using NALSA’s data from the test, the Guinness Book of World Records issued its concurrence. And in 2012, just for the heck of it, Cavallaro reconfigured the craft to prove it could go directly upwind faster than the wind, too. That was never so hotly contested, he knew. But if you’re going to do the impossible, you might as well be thorough.
*
Rick Cavallaro didn’t learn much about physics from the Blackbird experience—his plans were mostly based on the basics he learned at Tech—but he came to understand plenty about how people act when they’re wrong.
In the end, all of the right folks believed that the Blackbird did what it did. NALSA and Guinness gave him the thumbs up, Wired magazine ran several supportive features, and more former skeptics joined Mark Conroy in offering up mea culpas. But others became even more convinced that Cavallaro was wrong. Retorts moved beyond name-calling and into the realm of conspiracy: Some said the Blackbird had a hidden motor, or that the videos were faked, or that the Ivanpah lakebed wasn’t flat after all. And it wasn’t just laypeople or internet trolls; among his vocal deniers were professional scientists, researchers, professors at major universities.
Cavallaro was already familiar with how people can cling so fiercely to the tattered scraps of their own faulty notions. But it astonished him to see it play out in reality, and on such a large scale. Again he witnessed how the world seems to be divided into two kinds of people: those willing to admit their wrongness when confronted with compelling evidence against it, and those who dig deeper and deeper into denial.
But it’s tricky, he knows. The twist of the Dunning-Kruger effect is that a person can’t really know what it is he doesn’t know. Cavallaro tries to combat this catch-22 with a hair-trigger impulse to question his own assertions and admit his own ignorance. “I’ve had that experience more times than I care to, but I gotta tell you, it’s way better to be out in front saying, ‘Holy shit, I stand corrected,’” he says. “You never lose points for it, that’s the surprising thing. People think, ‘I’m gonna lose face if I’m wrong.’ No, you never do. You never lose face for admitting you’re wrong. You gain respect.”
When you’re right—especially when you’re right about something big, like the Blackbird—what comes next? Cavallaro isn’t sure. He’s considering going half-time at SportVision, where he’s now chief scientist, or retiring altogether; he’s itching to write, to teach. He’s also dead set on mastering the blues harmonica. (In typical fashion, his first attempt was a failure.) And he’d love more time for his wind-sports. By now he’s too old to die young, he notes, but he’s still happiest when he’s being flung through the atmosphere at maximum speed. He loves to feel the wind in his hair, feel his body battered by the weight of its own resistance.
So he’ll keep jumping off of cliffs and out of planes, snowboarding in the woods, waggling his fingers in the face of the impossible until he’s old(er) and gray(er). That’s why we’re here, he thinks—to be fearless in big ways, to push ourselves into the uncharted darkness, to take those wild leaps into the glimmering unknown.
Rick Cavallaro doesn’t believe in fate or destiny or God, but he does believe in that.
But then again, he could be wrong.















UNBELIEVABLE . Somehow it sounds like more energy out than energy in. I’m looking for the more conventional sail that would cause the Blackbird to move forward in a 15 mph wind. If the propellar is generating the power to drive the wheels, the thrust would approach zero as the craft speed approached wind speed And, if it got up to the speed of the wind, assuming 100 percent efficiency, the relative speed of the craft and the wind would be zero (wind speed minus vehicle speed). In that case, we could assume that the mechanical drive from the wheels to the propellar (assuming 100 percent efficiency) could be causing the propellar to rotate such that it would provide additional thrust to move the Blackbird forward relative to the wind. This load of the propellar on the drive train should act as a load on the wheels, causing them to slow down. I think the craft would remain well under wind speed.
i DON’T THINK i WOULD BELIEVE IT EVEN IF i SAW IT IN ACTION !!!.
I live in a retirement community of about 2000 retirees and we have a pretty sofisticated model airplane group. We have access to an abandoned aircraft runway where many test flights occur. If this is real, I would like to propose that our model plane group undertake a trial model of the lackbird.
Please reply tyo [email protected]
I agree Donald. I prefer to look at This from pure energy and energy conservation perspective.
The energy source in downwind motion is just that, the downwind. When the cart velocity is equal to downwind, the energy source is equal to zero. The only explanation for the cart to accelerate further would then be Stored kinetic energy obtained during acceleration, like flywheel energy in wheels, gears, propeller. But This energy will dissipate and cart lose velocity again.
Reageres
Lande
MsC
The simplest proof we offer (just a few lines of math) is based on energy conservation. What you’re forgetting is that when you reach the speed of the wind, the wind does not stop blowing - just ask somebody standing on the ground as you pass them by at wind speed. The point is that this vehicle doesn’t operate based on the speed of the wind relative to the cart, but rather the speed of the wind relative to the ground (that is what wind is after all). We are exploiting the energy available at the air/ground interface. We don’t make use of stored energy at any time. The vehicle can go uphill or pull a trailer - at windspeed - all day long.
Ok. I’ll look at the math. It just seems incredible that the moving craft can extract energy from windspeed relative to ground. But again tacking the wind…..
Regards
Lande
That was the original point. I originally posted it as a brain-teaser since it’s so counter-intuitive. I never planned to build the thing; nor did I imagine so much resistance to the idea after it was explained and demonstrated. I guess it was a better brain-teaser than I had thought.
Rick, I haven’t yet talked with anyone but I will. I just can’t understand where the energy input to the cart comes from. The propeller is driven by the wheels and, since nothing is pushing the cart when it is moving at wind speed, the load of the prop should slow the cart down. At any steady-state speed, energy input must equal energy output. I just don’t see what is pushing the cart to create the energy to drive the propeller to provide the thrust to move the cart forward. It’s sorta like me pulling upward on my shoestrings to lift me off the ground! The harder I pull, the higher I get!
Thanks for listening.
Don Lee
Donald - The Blackbird was taking up room I no longer had available to me, so is now being sold on Ebay: http://www.ebay.com/itm/Blackbird-Faster-Than-The-Wind-vehicle-/281114481020?pt=LH_DefaultDomain_0&hash=item4173ba917c#payId
You could buy it and try it for yourself on your R/C runway, but you’ve already said you would still not believe it. Alternatively, you could make a very simple model from videos I posted on YouTube, and demonstrate it on a treadmill. From your description above, it’s clear that you’re missing one very critical point - in downwind mode, the wind never ever turns the propeller. The wheels turn the propeller. Keeping in mind that the vehicle is traveling faster over the ground than it travels through the air, you can see that more energy is available to be harnessed than is needed to produce the necessary thrust. The vehicle exploits the energy available at the air/ground interface. This is why it can continue to propel itself even when moving downwind at exactly wind speed.
Rick ~ First, thanks for the prompt response to my comment. Maybe we can get something started here at Anns Choice Retirement Facility in Warminster, PA. The facility is built on the grounds of the former Naval Air Development Center and we have an active model airplane group here.
Gotta run now but I’ll get back in touch with you. Maybe we can verify that it really works on a portion of the old runway. We also have a large “multipurpose room” where many model planes and heliocopters are flown when the weathyer is not right for outdoor flying.
Donald Lee
31403 Anns Choice Way
Warminster, PA 18974
215-675-1720
[email protected]
I’ll certainly be more than happy to help you demonstrate this to the satisfaction of you and your R/C flying buddies. I think you’ll really like it.
Thanks, Rick. I’ll talk with some of the guys and see what we can do.
Don Lee
215-675-1720
Rick, cool concept. Is it fair to say that you are generating the additional thrust from the rotating wheels (w.r.to ground) and one can possibly also store that energy in other forms (battery, flywheel, compressed air, etc.) and use it to provide more controlled thrust (for e.g., when the wind speed goes down and one wants to maintain a constant speed).
Sreekanth, we do generate our thrust by exploiting the speed differential between air and ground. The reason we can generate more thrust than we create drag is that the vehicle is moving faster over the ground than it is through the air. Since work = force x distance, we simply trade less force over a larger distance (the ground) for more force over a smaller distance (thrust against the air). It does basically the same thing as a lever.