If you're interested in this kind of stuff, this German guy has a great channel on Youtube: https://www.youtube.com/user/JoergSprave https://www.youtube.com/use

If you're interested in this kind of stuff, this German guy has a great channel on Youtube: https://www.youtube.com/user/JoergSprave https://www.youtube.com/user/JoergSprave (his slingshot cannon is especially impressive)