Wind energy - Drinking straw furling wind turbine

I have to admit to being a little surprised when this one worked.

Here is my fully functional wind turbine made from three flexible drinking straws, three pins, a small piece of paper, and some tape.

The only tools required were a small pair of scissors, and the entire wealth of human knowledge as provided by the Internet.

Thanks entire wealth of human knowledge as provided by the Internet.

Thanks small scissors.

I started with the blades. Its probably easiest to see how these are made by looking at this previous post on blade twist.

Pictured here is the basic shape we are aiming for. On the drinking straw version, it will be a long thin version of this triangle looking thing drawn here.

In the cardboard version, the halves are connected by the thin, square, sticking out bit on the bottom LEFT, so the triangle bits on the top left become the leading edge of the blade. This one would rotate anticlockwise if the wind came from under the green thing in the background.

Bottom right tip goes up. Bottom left square bit is the centre.

The drinking straw version should look something like this. Its hard to see, but each blade has the same shape as the cardboard version. The straight sides (bottom on the cardboard picture) almost line up with each other.

The drinking straw version will also be made with two blades connected at the middle so there is no need to cut the straw in half. Just cut the required shape from a single straw. This means the blades will line up perfectly because both are made in one piece. Keep a small section of whole straw in the centre to aid in keeping the axle in place.

Jam a pin through the centre to act as an axle.

Now make a tail.

The only important thing here is to get the angle of the pin at around 20 degrees.

Don't be too fussy because its very easy to make a new pinhole.

You will need to adjust this a few times unless you are lucky.

Then make one of whatever you might call this.

The straw that goes out to the far right is to stop the tail swinging back too far (adjustable with bendy bit)

The bit that points up in the centre is the section that holds the tail pin. (also adjustable so you can play with that 20 degree angle a bit to see what changing it will do)

The bit that points diagonally up and to the left holds the turbine.

The device pictured above might be better explained by looking at a previous post where I described making the furling model.

Pictured left, is the design version of the three straw and tape thing pictured above. [I just noticed it's facing the opposite way just to be irritating]

On each of the three pins, you need to make a bearing to keep the pins from wobbling.

Just fold a section of straw in half lengthways, and stuff it into the straw where the pin needs to go.

This just makes the hole smaller.

One for the turbine (pictured), the tail mount, and the pivot point for the entire contraption to mount it to the straw we will use as the pole.


Next stick a folded straw bearing into a full length drinking straw. That's your pole. Stick everything else onto the pole, and it's done.

There are at least four points of adjustment that will let you learn some stuff.

1. The tail pin's angle. Making it slope more will make it furl later in stronger winds. Less,earlier in lighter winds. Adjust by changing the pin and/or the straw that the pin sits in (bendy bit)

2. The pivot point offset (the bottom most picture). Adjust it's position so that some balance is achieved between the blades desire to fold, and the tails desire to keep everything pointed into the wind. Shift it around randomly until it works. Mine worked best at the extreme left. If it still doesn't work try changing the weight of the tail.

3. Adjusting the weight/length/area of the tail can change when the device furls.

4. The tail stop point (bendy bit) that stops the tail from going back too far when its in the NOT furled position.

Remember if a bit doesn't work, it only take a few minutes to make a replacement part. I might have been lucky with my blades, but everything worked well enough to adjust some bits to get it right.

It might even be worth making a few different blades to see what they do.

Test with a fan, the wind, or even a brisk walk. Yes, you will look silly if you mount your wind turbine on a hat, but it's a small price to pay for knowledge.