Warning: Water Rockets and similar devices are dangerous. Anything you do with them is entirely at your own risk. Not Ours.

Intro

Flushed with the successs of our first water rockets, we made Nairn's rocket into a rocket car. It's pretty easy to do and seems to work rather well.

Making the rocket work

When the rocket is pointing upwards, gravity takes care of making the air force the water out of the rockets. When the rocket is horizontal, the air would just just escape past the water so you need to add a feeder tube to make sure that the water is forced out before the air. In the picture below you can see the feeder tube we added. The tube pushes into the inside of the bottle cap and curves down to the lowest part of the bottle.

Wheels

The only wheels we had to hand were from various Radio Control planes I've made and destroyed. The rear wheels are from my ill-fated Mini Laser 3D and the from wheels are spares I had laying around.

Running the car

You can use up to half water in the car as it doesn't have to lift it's own weight. If it's given a push as it starts to move it can travel quite a distance and is moving pretty rapidly by the end. We have some wideo of the car somewhere, which I'll upload when I get the chance.