whistling arrow
thingiverse
This is an attachment to the arrow that gets fired off to signal the start of combat. In medieval East Asia, it was shot out to kick things off in a battle. Check out this blog for the story behind its creation and test flights. http://dustofcosmos.blogspot.com/2018/09/3d-making-whistle-arrow-shoting.html
Download Model from thingiverse
With this file you will be able to print whistling arrow with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on whistling arrow.