Now we finish off the assembly of this catapult by installing the swing arm and wrapping the rope for torsion. The wrapping of the rope can be a bit tricky and how you wrap it will make a difference in the performance of the catapult. You can wrap it in certain ways that will make it absolutely ineffective. So, I recommend you watch the included video which shows you exactly how I wrap the catapult.

The picture below shows how I wrapped the torsion rope. Note that there are only a few of the rope passes that go through the center of the swing arm. This is to insure it stays connected to the rope. The majority of the wraps go either under or over the swing arm. In this example I managed to get 6 wraps over the top and 6 wraps underneath. Once this is done you are ready to twis the broomsticks on both sides to tighten it up.

The picture below shows the rope twisted up nicely. Twist the rope by turning the broomsticks in a forward direction. Don't just do one broomstick, do both. It will get nice and tight. And wear safety glasses when you do this just in case the rope snaps. I used a nylon rope which works very well. The tighter you wrap it the further the projectile will fly.

The Catapult is complete and ready to fire.

Table top catapult: The Troll
Rubber band powered

Mouse Trap Catapult -
fast to make

Table Top Torsion Catapult
(Also known as a Mangonel )