4'' plus quadcopter frame

This is a frame for a plus configuration 4'' quadcopter.
I can be printed with separate arms or the whole bottom part in one piece (frame.stl)
The arms interlock so there is no need for a bottom plate.

You can buy a carbon version of the frame on ARMATTAN
https://armattanproductions.com/pages/product_details/19721

Limitations:
20x20 stack only (2 layers with 6mm standoffs)
12x12mm m2 hole pattern motors only (most 13XX, 14XX, 15XX, 16XX)
max motor base radius 21mm

Can fit a full s