Can you build a wind-powered car and drive downwind at a speed greater than the wind? Doesn't sound possible, does it? Kind of like "free energy," getting something for nothing, right?
So, my old friend Dan Potter sent me some links to this effort that tests the concept. Engineer Rick Cavallaro and friends have built a wind-powered car that does indeed outrace the wind... so far, they've gone 2.8 times faster than the wind powering the car! In a 14mph wind, they were clocking about 35mph.
Cavallaro's claims that this could be accomplished kicked off a huge debate about the possibility or impossibility of this concept on geeky websites, like Skepticblog and BoingBoing, and even in college classrooms.
Check out the Switched article below, which includes a video of the car in action in the California desert.
http://www.switched.com/2010/07/08/wind-powered-car-outraces-the-wind-leaving-legions-of-net-nerds/
The link to Wired website here features a video that explains the physics of the concept, to show how it is indeed possible to go dead downwind faster than the wind:
http://www.wired.com/magazine/2011/02/ff_fasterthanwind/all/1
Here's a link to their blog, too, where you can follow Cavallaro and friends in the effort to improve the performance and construction of their wind-powered vehicles:
Ride Like the Wind (Only Faster)
I just added this video submission to the Mythbusters challenge, lots of background info in it.