This is rev.1 of my 3D printed drone racing frame. Suitable for 5inch propellers and 3S/4S LiPo has a place for "standard" FPV camera and 36x36mm flight controller and PDB (30.5mm hole spacing).
Edit: current version has 2 different arms: "Arm.stl" and "Arm v2.stl". V2 is much stronger design, but still experimental. I suggest printing V2 arm with ABS or PET-G with thick walls (1.6 or 2.0mm) and at least 40% infill. It is heavier, but should not break that easily
Print with thick walls for max. strength. I'm used 2mm thick walls
To assemble you will need:
8x M3x45mm bolts
4x M3x12 bolts
12x M3 nuts
A lot of M3 washers. I suggest a washer for each nut and bolt
Depending on the thickness of your flight controller stack, you will need 4 additional M3 nuts and bolts. You can either just attach your stack with M3x20 or something like that, but for better frame stiffness I suggest printing some standoffs and attaching everything with 4 additional M3x45 nuts through the top plate.