Designed to fit 6" airframe
The 6" Sections have a 6mm channels for adding carbon fiber rod to help strengthen them.
4th stage is a 4" tube.
Work in progress - I will be adding the .STLs as I test print them
I'm modeling this in Fusion 360 - you can check the progress here. https://a360.co/2FOR3o3
Feel free to download it there if you want to work with the files on your own.