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  • Recently some friends of mine went to the Gordon dam in Tasmania

  • which is a hundred and twenty-six and a half meters or four hundred and fifteen feet high.

  • then they drop a basketball over the edge.

  • you can see that the basketball get pushed around a bit by the breeze.

  • but it lands basically right below where it was dropped.

  • Now watch what happens when they drop another basketball.

  • This time with a bit back spin.

  • wow! where will it go? hahaha (It's incredible!)

  • So you want us to get back in the water, do you?

  • This is Brad who just threw it.

  • I literally just dropped it with a bit spin like I didn't even throw it.

  • and I just took off. I have no idea that I'm gonna do that.

  • And this is where I come in. The basketball with subject to the magnus effect

  • which affects all rotating balls are cylinders as they fly into the air

  • and it works like this.

  • as the basketball picks up speed, air on the front side of the ball is going in same direction as it's been.

  • and therefore it gets dragged along with the ball and deflected back.

  • Air on the other side is moving opposite to the ball spin

  • so the flow separate from the ball instead getting deflected.

  • The net result is the ball pushes air one way so the air applies in equal force in a ball the other way.

  • and this is known as the Magnus effect named after Heinrich Gustav Magnus who described it in 1852

  • of course Isaac Newton beat him to it by nearly two hundred years describing the flight of tennis balls at Cambridge College

  • but you know he's got enough stuff named after him.

  • This effect is very important in sports like tennis, soccer and golf

  • but could it have non-sport applications?

  • Perhaps this is a sailboat. I know it doesn't look like a sailboat but those aren't chimneys

  • they are spinning cylinders called flettner-rotors and they take the place of the sails.

  • They deflect crosswinds using the Magnus effect to propel the ship forwards

  • In this, it's a plane with spinning cylinders instead of wings

  • using the Magnus effect the cylinders actually generate more lift than traditional wings

  • however they also generate way more drag making them impractical.

  • this plane only flew once and then it crashed

  • but a man is in fact is making a comeback

  • here's an experimental rotor wing aircraft which generates all its lift from spinning cylinders

  • and this is the E-ship 1 which uses four spinning cylinders that is four flettner rotors

  • to increase its efficiency and reduce the amount of diesel

  • so in the future, the Magnus effect may help more than just basketballs' fly.

  • Oh, where will it go?

Recently some friends of mine went to the Gordon dam in Tasmania

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B1 US magnus effect spinning ball air sailboat

Surprising Applications of the Magnus Effect

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    Claire Chi posted on 2015/07/24
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