How to Build a Lego Trebuchet

A trebuchet is a siege weapon based on the physics and construction of a large lever. It was the weapon of choice by many in medieval days because it was efficient, accurate, stable and simple to build. There are basic steps you need to follow when you construct a miniature Lego trebuchet, but the project allows you to experiment with your own ideas and ingenuity.

Instructions

Basic Project

1. Construct the base that will hold an A-frame. Determine the dimensions of the flat Lego mat by the size of the A-frame you will build.

2. Situate struts parallel to each other on two sides of the base to make a basic A-frame. Build upward on each side until you have a triangular like shape.

3. Attach a connecting axle between the two A-frames on the top. Make it strong enough to bear the weight of a swinging arm.

4. Build an arm that is twice as long as the A-frame is high. It should look like a long pole and work on the same principle as a teeter-totter.

Firing Mechanism

1. Cut fabric in a rectangle to form a sling. Put a hole in each end of the sling.

2. Take one piece of string and tie it to one hole, and tie another string to the other hole in the sling. Attach the strings to the arm; experiment with the string length to find out what works best.

3. Add a counter weight to the end of the arm that is opposite the sling to construct a Lego trebuchet.

4. Place the winch in the center of the mat between the A-frames. Put a string from the winch to the arm.

5. Wind the string around the winch. Experiment with the best way to lock the string or pinch it in place until you're ready to release it.

6. Find a projectile and place it in the sling. Release the string on the winch to launch the projectile from the Lego trebuchet (see Resources).

Resources

• See trebuchet project pictures on Weird Richard.com.