Make sure that when it does come down it won't cause any damage, especially to people.
OK, now we can start.
You need two bottles, scissors and some duct tape.
One bottle is the rocket motor.
The second bottle needs to be cut in two places:
1. cut off the top of the bottle
2. cut off the bottom of the bottle so that you are left with a cylinder of PET (this will be the tail of the rocket)
Tail: cut three square holes in the cylinder of PET (see the picture bellow)
Slide the nose cone over the bottom of the first bottle and the tail over the neck of the same bottle. Make sure they are straight.
And final, tape it up with the duct tape.
Half fill with water and put it onto your launcher ready for launch.
If you want it to go really high, put a small amount of water into the nose cone (don't fill it and don't cap it). It might be a good idea to pump the bottle up to 1 bar (no more) before you do this.
You can see HERE how to make a rocket launcher.
Jul 18, 2006