After seeing a video on youtube about an airhorne made in wood (search for 'obnoxious air horn'), I decided I would try and print one myself from the same approximate measurements. After finding thing 2859 and finding it to be inadequate and not properly designed (middle tube should protude a little from the outside edge, and the hole in the side should have been included in the model) I decided to crank one together myself. Printed on an UM original. 0.8mm top and bottom layer, reasonable thick walls (at least 0.8mm) and 40% infill (less might be ok as well) at 90mm/s. Wrap a balloon over the top (where the middle tube is protruding) and fold it back so the balloon is tightly fitted with no wrinkles (pictures will follow). This takes a little practice the first time as you might feel like you need a 3rd hand. Blow hard into the hole in the side. Adjust balloon for proper tone and remember - this thing is loud!