How to Build a Lego Trebuchet

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

• 5

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

• 6

  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.

• 7

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

• 8

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

• 9

  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.

• 10

  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).