Wind-Powered Car Travels Downwind Faster Than The Wind

A good visual analogy:<p><a href="http://www.youtube.com/watch?v=E7vcQcIaWSQ&#38;feature=related" rel="nofollow">http://www.youtube.com/watch?v=E7vcQcIaWSQ&#38;feature=relat...</a>

General explanation of how this is possible:<p><a href="http://terrytao.wordpress.com/2009/03/23/sailing-into-the-wind-or-faster-than-the-wind/" rel="nofollow">http://terrytao.wordpress.com/2009/03/23/sailing-into-the-wi...</a>

I can see why it's a hard thing to come up with, but I'm puzzled as to people's problem accepting it.<p>The blades create backward-thrust, pushing against the wind, accelerating the car, creating more thrust, pushing harder against the wind, etc. It stops a seemingly-endless increase when you hit the break-even point.<p>The reason it goes <i>faster</i> is because, when it finally catches up to the speed of the wind (which is obviously possible), the blades are <i>already spinning</i>, thrusting the car forward beyond just the wind speed. If they weren't spinning at all, 1x wind speed would be the max, fairly easily approached (though not <i>achieved</i>). This video is particularly telling of this effect: <a href="http://www.youtube.com/watch?v=dgHBDESd38M&#38;feature=related" rel="nofollow">http://www.youtube.com/watch?v=dgHBDESd38M&#38;feature=relat...</a>

It seems like they're using the propeller as a combination flywheel / accelerator. If you're allowed to store energy as rotational momentum, why not in a battery?

From the article: “I thought people would say, ‘That’s cool,’ but they didn’t. They said, ‘Wow, you’re an idiot.'"<p>If I had a dollar for every time I heard that ...

No explanation within the article. That was annoying.<p>Any ordinary sailboat sails faster than the wind when going roughly perpendicular to the wind direction. But this is apparently something different.

When I follow this link in my iPhone I get redirected to wireds mobile site. Is anyone else experiencing this?<p>It really grinds my gears when websites do this! Grrr

<i>" Yes, it’s possible that SJSU, Google, and Joby Energy are all being hoaxed here. What do you think?"</i><p>Could be, especially considering the video linked on this page to the treadmill demonstration. I'd like to see this "blackbird" actually "spread its wings" on more than a short sprint, after a thorough inspection. I suspect its average speed would end up below that of the wind.

A helpful way to understand sailing into the wind (for me at least) is to think of a stationary wind turbine producing eg. 2MW of power. Now if you were to mount that turbine on the roof of your electric car, that 2MW is more than enough to power the car at great speed in a windward direction. This seems to be the same concept except with a pure mechanical linkage.

This seems to be the same issue as horsepower: If the engine has horsepower doesn't that mean it can only go as fast as horses do?<p>Of course not, that's the intuitive "apples and oranges" type mistake, the two numbers aren't really correlated like that. It's like leaving your foot on the gas at the same level will keep it accelerating until it hits the most it can do with that much gas.