Introduction: Simple Trebuchet

Whether you want to make it for fun or have to for a school project, this easy step by step instructions will help. Trebuchets or catapults are based on an arm which has weights on one side and a projectile being launched from another. It required a lot of trial and error but we eventually got ours to work very well.


1. A stead base (anything stable we used a bike rack and moved it until it was the same we wanted)


3. PVC pipe

4. Pipe cutters

5. Nail and hammer

6. Golf ball

7. Duct tape

8. String

Step 1: Making the Arm

The arm is the most important part of the launch. There is really no trick to it besides trial and error. It has to be longer on the top and shorter underneath the axle where the weights sit. Once you create it you need to find a way to attach it to a base. The base needs to be study and allow the weights to move around underneath.

Step 2: Projectile

At the tip of the arm we attached a nail to clip our ball too. The ball is connected to string and we attach it to the nail before the launch.

Step 3: Test It

After testing it, we made the arm slightly shorter as well as the string on the ball. We found that slight adjustments make the biggest difference.