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Google-Backed Wind-Powered Car Goes Faster Than the Wind

Posted by timothy on from the duh-it's-pushed-by-the-google dept.

sterlingda writes "A wind-powered car has been clocked in the US traveling downwind 2.85 times faster than the 13.5 mph wind. The definitive research by Rick Cavallaro of FasterThanTheWind.org is being funded by Google and Joby Energy. The run should now settle the DWFTTW (downwind faster than the wind) debate that has been raging for some time on the Internet about whether or not such a feat was possible."

3 of 393 comments (clear)

  1. Debate? by Mikkeles · · Score: 4, Interesting

    Sailing vessels can go faster than the wind, why shouldn't a car be able to?

    --
    Great minds think alike; fools seldom differ.
    1. Re:Debate? by dtmos · · Score: 4, Interesting

      Ah, no. I can do no better than to quote ThinAirDesigns:

      The key thing to remember is that due to the tailwind, the wheels are traveling over the ground much further than the propeller is traveling through the air[1] -- thus using the force x distance calculations for work and power it's easy to see that when we are traveling the speed of the wind, we can gain more power from the wheels (faster moving ground) than we have to expend in the air (slower moving air).

      ________
      [1] As he is about to mention, this is best considered at the moment when the car is moving at the speed of the wind. In this case, there is no wind over the propeller, since the car and the wind are traveling at the same rate in the same direction; however, the wheels are moving relative to the ground at the speed of the wind, and therefore turn the propeller and supply additional thrust to the car, accelerating it.

    2. Re:Debate? by SerpentMage · · Score: 4, Interesting

      Look at the experiment I would say sure its possible because there is no resistance. As they say they can't do this on a gym floor, but a tread mill.

      As a mechanical engineer who studied dynamics I would say the reason is because the resistance that is normally hit due to acceleration or keeping the thing moving is not present. Thus this thing could accelerate faster than the wind.

      What I would find interesting is what are they exploiting in specific? As they say, is there some neato resistance, aero-dynamic trick that nobody has yet thought of?

      It reminds me of the ram jet that below a certain speed is useless. YET at higher speeds it becomes more effective than a regular jet.

      --

      "You can't make a race horse of a pig"
      "No," said Samuel, "but you can make very fast pig"