Whistle to install in my Freewing F15. You can adjust pitch by printing main whistle and adjust Z height in your slicer. Also you can scale it down. Make sure you support outer edge when printing. Inside of whistle can also be supported but use minium amount as it makes cleanup easier. I also added a domed cap that I found works better. Updated to latest tested design.
Here it is in action.
Print with 3 outlines, 3 bottom, 4 top.