Build a Wind Turbine

There are two kinds of wind turbines that you can create, depending upon how much time you have and what materials are available. The first type is the common "pin-wheel". It can be attached to a pencil, a dowel or to a flat stick with a push-pin. The second type of turbine is made from a plastic disk. It can be attached to a small machine or simply used in the same way as the pin-wheel to demonstrate how moving air can be converted into mechanical energy.

TYPE 1:Instructions

• Using a square piece of paper draw diagonal lines joining each corner.
• Cut in from each corner one half the distance to the centre.
• Fold each corner as indicated in the illustration to the left and tape or glue the folded corner at the centre.

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A simple child's pinwheel is made up of brightly coloured mylar sheets, trimmed and folded exactly as the four-cornered pinwheel shown here.

Small pinwheels have an exceptionally high strength to weight ratio and can withstand fairly strong breezes.

Traditionally engineers have found that they do not scale well, that is, as they get bigger they begin to break under the force of even the slightest breeze.

TYPE 2: Instructions

• Using a large plastic lid from a coffee can, peanut can, or margerine container, draw a series of diagonal lines through the centre as shown in the illustration to the left.
• Cut from the outside edge in towards the centre, leaving about 2 or 3cm uncut in the centre. This creates the vanes of the turbine.
• Strongly twist all the vanes in the same direction. A dab of glue in each corner of the vane near the centre of the disk will help them to hold their twist.
• Drilling a small hole through the centre of the turbine and glueing an empty spool over the hole as shown in the figure to the left completes the turbine. A large nail, pencil or wood dowel makes a fine axle for the turbine. Make sure the spool is attached securely to the turbine. Make sure the spool turns freely on the axle.

The preceeding photos illustrate the main elements of a successful wind turbine. A glue gun, a small electric drill, and set of drills are very useful. Nylon spools used for holding thread are almost perfectly frictionless when rotating on a smooth pencil axle. The plastic lids from disposable food containers make excellent turbines. Try various designs to optimize their efficiency.

For Advanced Builders

The energy from the wind can be harnessed by this simple machine. It's dimensions are not critical but here are some tips based on experience.

1. A large nail works best as the top axle since the head of the nail prevents the spool from sliding off the shaft.
2. The two bottom spools must be glued to the axle. Once they are glued in place they cannot be removed!
3. An elastic band makes an excellent "belt" to link the top spool to the bottom spool.
4. Choose the elastic band carefully. If it is too tight it causes the rotating components to "bind" and your machine won't work.

A small disk can be glued to the spool to provide mechanical output from the wind turbine. A push-pin can be used to attach a drive link made from a straightened paper clip. The work performed by the wind turbine is left to the imagination of the builders.

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