An American engineer called Rick Cavallaro was presented a brainteaser: could a sailboat sailing downwind outrun a balloon?
The question is an old sailing stumper with quite a bit of physics involved. Sailboats use sails to produce lift as long as there is wind moving across them. The sailing speed in that case is the speed of the wind itself. So to beat a balloon, a sailor must navigate at an angle to the destination, then tack, or turn, the boat back toward the finish line. This downwind zigzag course – jibing, in sailing terminology – is often the fastest way to traverse between points A and B. But given that you have to cover more ground and take the time to turn, is it really fast enough to beat the wind itself (represented by the balloon)?
It turns out that, counter-intuitively, it is indeed possible to sail faster than a balloon. But there is a catch: only if you are sailing in some speed-record- smashing yacht.
Cavallaro wasn’t specifically impressed with high-performance sailboats. He felt he could do something more daring. So in 2006 he posted a brainteaser on the internet: can you make a vehicle that goes directly downwind, powered only by the wind, faster than the wind? His focus was on the “directly downwind” part: no zigzag.
The problem is that not only had no-one ever managed to make a vehicle like this but the physics involved show it to be rather impossible. It is the classical energy conservation problem: You can’t get something for nothing.
Cavallaro started to be ridiculed all over the place. His ideas were debunked over and over again and reached publicity on Make magazine where Charles Platt wrote a story entitled “The Little Cart That Couldn’t”. Rhett Allain, a physicist at Southeastern Louisiana University and a blogger for ScienceBlogs, diagnosed what he called the “free energy” problem and concluded it was impossible.
The Internet consensus remained and it bothered Cavallaro very much. He knew he was on to something. Not shying away under the critics, he started an endeavor for sponsorship to build his machine. He visited local universities and sailing clubs, made presentations at San Jose State University, Stanford, and the St. Francis Yacht Club in San Francisco. He almost managed to speak at UC Berkeley but was rejected by the head of the school’s Renewable and Appropriate Energy Laboratory with an email saying the principle was not possible “due to conservation of energy”.
Nobody believed Cavallaro until he bumped into Google’s Larry Page, who decided to sponsor Cavallaro’s pet project. With the little money collected, he built a scale model and then a full-sized vehicle that he named Blackbird.
In 2010 he took Blackbird to the Mojave Desert for a series of trials. The vehicle not only managed to outperform the wind but also did it at such a high performance that the sail-prop used in the contraption spun faster than what Blackbird’s makeshift structures were designed to support and the vehicle was damaged after its third trial run. The sail-prop was spinning so fast that it inflicted roughly 470 foot-pounds of torque – about the same as the V-8 in a new Corvette Z06 – on a drivetrain made of bicycle parts.
However, the two first runs were amazingly successful and left skeptics dumbfounded.
Cavallaro returned from the Mojave Desert as a hero. He proved his idea stood solid against all odds. He believed himself in the barely believable even when everyone else thought his concept was crazy. And it is important to notice Larry Page’s boldness in supporting the idea as well. If it failed miserably, it would fail with big Google logos stamped all over the contraption. Google’s risk was not the USD10.000 Page decided to give Cavallaro, but the potential image damage.
At a conference at Google’s headquarters in Mountain View, Larry Page personally drew Cavallaro aside to talk about other possible uses for the technology. They are now estimating that exploring the technology on cargo ships could reduce up to 10 percent of their fuel costs. That would mean a billionaire business in the next decades. All out of a simple idea nobody believed in.
Are you ready to believe in the unbelievable ideas?