Motoramic

Wind-powered Blackbird vehicle up for sale after rewriting physics

Alex Lloyd
Motoramic

Rick Cavallaro has been called an idiot more times than he cares to remember. After posing the theory that a wind-powered vehicle can travel downwind faster than the wind, negating centuries of scientific belief, the Internet and its readers pointed, laughed and ridiculed the mad scientist. But on July 3, 2010, Cavarallo and his cronies silenced the doubters by constructing a wind-powered vehicle that travelled close to three times faster than the wind itself.

For those wondering where one might buy a scientific-defying wind-powered machine, head over to eBay. The car nicknamed Blackbird is now for sale.

How can a vehicle powered entirely by wind travel directly downwind faster than the wind itself? If you asked Nobel Prize winners a few years back, the verdict would be unanimous: It can’t.

Cavallaro disagreed: “You lose the power of the wind when you reach the wind speed, because there is no relative wind at that point,” he once told Wired.

“Skeptics think that the wind is turning the prop, and the car is turning the wheels, and that’s what makes the car go,” Cavallaro said. “That’s not the case. The wheels are turning the prop. What happens is the prop thrust pushes the vehicle.”

While this may sound like perpetual motion, it’s not. The wind is harnessed as an external power source, allowing the additional power to propel the vehicle faster than the speed of the wind.

After Internet ridicule, Cavallaro and his associate John Broton sought to prove the concept by creating a small model. Having established that once wind speed is reached, there is no wind across the chassis, all that was needed was a moving floor wind tunnel with the wind turned off. Or, in scientific terms, a treadmill.

The theory was simple: Set the treadmill to a certain speed to simulate the moving ground, place the model on the treadmill as if it’s traveling at the same speed as the wind, and if it moves forward up the treadmill, it’s moving faster than the wind.

After posting their successful tests, the world deemed it a hoax.

The only option left was to build an actual wind-powered car, race the wind, and beat it. After securing help from Google and Joby Energy, as well as assistance from San Jose State University, work began.

Made from mostly lightweight foam, the aerodynamic shell sports a 17-ft. tall propeller. Bicycle wheels reengineered with go-kart hubs (to handle side-load) were installed, and, after more than a year of trial and error, a transmission was developed capable of transferring power from the wheels to the giant prop without breaking.

On May 17, 2010, at New Jerusalem Airport in Tracy, Calif., Cavallaro and his team faced a wind speed of 13.5 mph. The wind-powered vehicle did more than just outrun the wind: it sped to 38.5 mph – 2.85 times wind speed.

On July 3, under the watchful eye of the North American Land Sailing Association, Blackbird entered the record books, making its claims official by posting 2.8 times the speed of the wind, as ratified by Guinness.

In July 2012, the team modified the Blackbird to travel upwind, recording a pace 2.1 times faster than the wind, further cementing their place in history.

Cavallaro and Broton were not the first to believe in this theory. The first wind-powered vehicle documents back to 1969, when Andrew Bauer created a wind-powered machine that, supposedly, could outrun the wind too. While there is no reason to doubt these claims, evidence of its success remains slim.

Defying established beliefs, this piece of scientific history holds a current bid on eBay (as of this writing) at just $1,575. Cavallaro told me they're selling it because "we're done with it, don't have space for it, and don't want to cut it to pieces." Who needs a $70,000 Tesla? This is a real zero-emissions vehicle. Just don't ask it to turn corners.

Photo: Rick Cavallaro

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