This is an interesting little catapult idea that I had and I finally got to making a prototype of it. The concept is that the catapult fires from the upside down part of the swing arm. Kind of hard to describe in words so I will show you some pics and give you my thoughts on how I made it work correctly.

Here is a picture of the completed Undepult

This graphic shows you exactly how the underpult works. Rather than throwing the projectile from the top it throws from the bottom.

But this kind of a catapult setup causes a bit of a problem. The graphic here shows that. When you draw back the throw arm to fire it the projectile is going to fall right out of the cup! So, we have to design something to fix this. We want the projectile to be held in the cup with the throw arm drawn back but we want the projectile to freely release at the point of fire.

To solve this problem I created a little setup called The Caddy. It holds the projectile throughout the swing of the arm yet lets it release freely.

It's a little bucket that hinges on the swing arm. You can see the clay projectile ball in the caddy.

This picture shows the caddy in the loaded position. The tension is now on and it just needs to be released to fire. See how the caddy stays horizontal and hold the projectile in place?

And this picture shows the catapult just at the moment of fire. The throw arm slaps directly against the stop. This holds the caddy tightly in position and releases the projectile to fire.

I have a video showing this catapult. You can learn more about it and see how it works right here:

The Catapult Projects

New Catapult Project This is "The Ogre" and it is built from 2x3's and uses a bungee cord for power. The base is two feet long and you can get a sense of the size by the safety goggles in the picture. It took me about two hours to build this catapult and I am making complete plans so you can build one too. This is not a toy! And you must wear safety glasses when building and when using it. Doesn't take a lot to build though, just some wood, a bungee cord a couple of hooks and some tools like a saw and drill. The plans and tutorial are here so you can check in and see my progress

The History of Catapults

The Engineering of Catapults - The basic concept of the catapult is not an arm that fires a rock. The basic concept of the catapult is using any means available to store a lot of energy then in one quick release of that energy to fire a heavy projectile a long distance.

Catapult Videos

Catapult Kits to build your own Catapult

Books about Catapults, and Making Catapults

Web Resources for Making Catapults

Unusual and Unique Catapult Stuff

15 Dangerously Mad Projects for the Evil Genius

This wickedly inventive guide explains how to design and build 15 fiendishly fun electronics projects. Filled with photos and illustrations, 15 Dangerously Mad Projects for the Evil Genius includes step-by-step directions, as well as a construction primer for those who are new to electronics projects.

Using easy-to-find components and equipment, this do-it-yourself book shows you how to create a variety of mischievous gadgets, such as a remote-controlled laser, motorized multicolored LEDs that write in the air, and a surveillance robot. You'll also learn to use the highly popular Arduino microcontroller board with three of the projects.

Do you like making projects and exploring a variety of hobbies?

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