Building a Lego catapult

Building the lego machine-catapult

Matthias Wandel publishes on YouTube and a blog about building a rapid firing motorized machine catapult out of Lego. The latest design shoots plastic baby food caps at a rate of about once per second. It uses a rack and pinion mechanism to tension the catapult, then pulls back the mechanism and loads a cap before releasing.

I had the idea of building a better motorized repeating shooter out of Lego. Searching for “lego machine gun”, I came across a lot of models of machine guns, but at best these shot rubber bands. The closest to what I could find was this video, but, ironically, that machine gun was one I designed and published in 2001, the very design I wanted to improve on!

A catapult would be a more effective way of throwing something fast (lever advantage), so I started with designing a catapult mechanism.

I wanted to make it so the catapult arm would have as little encumbrance to swinging as possible, which meant the whole pull back mechanism should be decoupled from the catapult when it’s released to fire.

Check out the excellent build video and the blog post and other projects on the site.

Are you a LEGO fan? Let us know in the comments below.

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