Launch It: the Zero-Wind Indoor Pizza Kite

You're bored. You're desperate to fly a kite, but it's raining.

Have a pizza while you read the rest of these instructions.

You will need:

The polystyrene disc from under a store-bought pizza.

Sharp knife ("X-acto" or similar. The ones I use come under the heading of "similar" - they cost me £1.99 ($3-$4) from my local Morrisons Supermarket).

Scissors.

Sticky tape. You may need to use duct tape: if your pizza base is greasy, normal tape sometimes won't stick.

Sewing thread.

Wool.

Optional: paper template. I needed to use the template because my pizza base was black, and so is my pen. Some bases are white, and you can draw your pattern directly onto them.

The shape we are going to do is my own variation on a traditional diamond kite. My boys call it a fish kite. You can experiment with shapes, but remember that,as a rule, they need to be symmetrical.

The template:

Cut a square, and draw a line corner-to-corner. Mark a point one quarter of the way along the diagonal. Draw lines to the other two corners and cut along them. You will have a wide kite-shape and a chevron.

Stick the chevron back on the square, but at the opposite corner to the one you cut off. The diagonal line on the chevron should line up with the diagonal line on the larger part. Check the photos to see what I mean.

Draw the shape onto your pizza-disc (most of the flat pizza bases seem to have a pattern of square dimples, which makes life easier - you can count along them and use them for guide-lines if you want to draw your shape directly onto your base) and cut it out with the sharp knife.

Cut eight pieces of wool about 60cm (two feet) long and knot them into two bunches of four.

Tape each bunch to one of the points of the "fish tail" - put the end of the wool next to the point of the kite, sandwich them in the tape and trim off the excess.

Find the point which used to be the centre of the square, and move a centimetre or two along the centre line of the kite towards the tail. Pierce through and thread the sewing thread through. Tie a large knot at the back of the kite and anchor it with a small piece of tape.

You are now ready for a test flight.

Normally, kites fly by deflecting down a mass of moving air. By Newton Third Law, deflecting the mass of air down deflect the mass of the kite up. This NASA image shows the idea.

Unfortunately, sometimes the air doesn't move. That's when this kite comes in - it is light enough that it takes very little motion to give it lift.

You can take this kite for a walk, or just circle on the spot to get it air-borne. If you're going to stand still, though, I would fasten a short flying line to a length of bamboo or cane - wave it slowly around to fly your creation. A narrow figure-eight motion helps prevent tangles between tail and flying line.

If the kite is unstable, there are a few things you can do. Try them in this order, as the last one is hardest to undo:

1. Slow down - don't run around the room, walk.

2. Lengthen the flying line by a metre or two to let the kite fly away from the turbulence generated by your body.

3. Lengthen the tails by about 15cm (six inches).

4. Bend the kite - using a ruler and the blunt side of a blade, score down the centreline of the back of the kite, then gently crease along the score so that both side move up slightly. If you make a mess of this, you will have to start again from scratch.



Although this is officially an indoor kite, it will fly outside in light, steady winds, or it can be taken for a walk along the beach...