Some time ago I decided to design one of the smallest possible 3" FPV racers.
It fits 3" props, 13xx-14xx motors, a 20x20 FC and a runcam mikro swift (or similarly sized camera).

31*31mm hardware would fit the frame as well (45° rotated to the flying axis), my pod will not fit anymore then, as it uses the 31mm holes as mounting points.

The pod is designed to be printed using flexible filament, without supports (though it will sag a bit in the rear).

It flies amazingly well and is a lot of fun, as well as very hard to break. Building can be a little tricky and frustrating, as everything has to fit underneath the pod somehow... I managed, so you will manage as well, though. And the result is totally worth it.

My hardware (guaranteed to fit, similar hardware should of course fit as well):

• HGLRC F428 (FC + 4in1 ESC stack)
• Armattan Oomph 1407 (shafts are very fragile, stay clear of them)
• HQprops 3x4x3v1s
• Furious FPV Stealth (no Bluetooth, but it would fit somehow)
• RotorX u.fl Whip antenna
• Runcam Micro Swift 2
• FRsky R-XSR (antennas taped to the inside of the pod)
• 4S 850mAh Acehe
  Total weight (with a 3mm base plate) ~260g.

Printrbot

Printrbot Simple Metal

No

No

.2 layer height, .4 nozzle

Doesn't really matter, ~20%

Print with flexible filament! I used FilaFlex TPE.