This item is a hand-crank air raid siren that is 100 percent 3D printable. It has two rotors so that it can produce sound from both ends. I have not 3D printed it yet as it will take a while to print. i also have to print our two of mostly every piece. I will upload pictures and a video when I do get around to 3D printing.
You may need to use a higher infill on the rotor/flywheel as it needs to be much heavier so that it can carry momentum over a longer period of time and still produce sound.