The Orange Screamer

Source: https://www.thingiverse.com/thing:455093 Summary This is a pocket sized turbo whistle or siren which emits a loud and extremely annoying WHEEEEEEEEEEE when you blow into it. This design was inspired by Instructables user Kiteman, who published a perspex laser cut version. Instructions The rotor sits on the spindle and then the lid is glued on with cyanoacrylate adhesive. However, you will get best performance if you slightly sand the parts in contact to get rid of any roughness left from the printing. A drop of light oil or silicone spray in the works before gluing will help things too. Reducing friction is the name of the game.