FR3/FR4 Quadcopter Frames

This is an evolution of the FR7 open-source quadcopter frame. All proportions of the FR7 have been scaled down to create a functional 3" and 4" quadcopter while maintaining the same aesthetics.

The features include
- Interchangeable centre frame for both 3" and 4" arms.
- 3" arms fit 1306/1407 motors, and 4" arms fit up to 1806 motors (M2 and M3 versions).
- Top plate fits up to 2000mAh 4S.
- 25deg and 30deg Session TPU mount with TBS Jello Guard ND filter insert.
- Micro cam mount integrated into GoPro mount
- Twin 20x20 stacks (M3) and a 20mm stack height.

The designs are intended for 1.5mm main plates and 2.5mm arms. Thicker plates can be used, but will require modifications to the GoPro mounts (coming soon).

The required hardware for the frame and GoPro mount includes
- 8x M3x5 button head screws for plates
- 3x M3x8 button head screws for GoPro mount
- 2x M3x6 button head screws for arm connections.
- 2x M3 24mm length 5mm OD threaded round spacers
- 3x M3 20m