A Super Simple K'Nex Catapult

I have been reading & building stuff off instructables for a while now. I thought it was time to contribute.

Here is my first instructable: a simple but effective catapult. it fires about 2 feet, but shoots it really high.

it uses marbles, but small sinkers work as well.

Ready to build: continue to step 1.

Step 1: Parts

Below is a list of parts. Gather them now.

Step 2: Frame

Build two of the below pictures.

Then, join them together. see last pic.

Step 3: Tensioning Mechanism.

This is a little hard to explain, but here goes.

First, set it up as shown in the first two pictures.

Then, wind a turn on until you see picture 3.

Step 4: Ammo Arm.

I don't know what to call it, but you've got to build the arm that holds ammo and fires it.

If you know what it's called, comment & tell me.

Step 5: Stabilisers.

Join the catapult ammo arm as shown in pic one.

Then, Add stabilizing rods.

Step 6: Done!

Please comment highly, and nicely, on this.

First time!

Enjoy the catapult and win your office territory back.