This is a spinning whistle thing that makes a very loud noise, and I mainly designed this for the #MakeItLoud challenge. I tested the loudness of the design and I got 97dB on the original size. With this new version you can change the size of the sides to get different sounds that can be low or high.
I recommend printing this at 0.2mm resolution or higher to ensure the parts will fit together.
After you print the body piece, lid, and two propellers all you need to do is put one propeller into the left and one into the right side of the body and then maybe add some lubricant, I used vegetable oil, and then snap on the lid, but make sure both propellers spin. For mine, my left propeller wouldn't spin so I lifted the lid a little on the left and it worked perfectly. If you didn't have to adjust the lid at all then you probably don't even need to glue it shut, but if not then simply use super glue to keep the lid from moving.
I got the idea of the design by looking on Thingiverse and finding The Orange Screamer - http://www.thingiverse.com/thing:455093. Since I wanted to make it different and didn't want to just remix it I made my own design, so I started my first prototype and that was a complete failure. Then for my second prototype i basically remixed it but then it didn't feel right to enter it into the contest. So my third prototype is what is now my final product which I feel is a new item instead of a remix.