4 inch FPV quad frame

An organic 4 inch FPV frame in PETG with bolt-on arms, so a crash costs one arm, not the frame.

Props: 4 in
Wheelbase: 189 mm
Print time: 3.6 h on 3 plates
Filament: 107.3 g

Colourway

PETG HF lake blue main
PETG HF blue second
PETG HF white accent

About the design

A true-X frame for 4 inch props with swept, bone-like arms, a camera cage of two arched side plates, and the battery strapped high on top. Each arm is clamped under the bottom plate by the stack's bolt and a standoff's screw, so a crash breaks one arm, not a unibody frame. The wheelbase follows from the prop size, keeping every prop clear of its neighbours and of the body. The arms are deepest at the clamp and print solid, which puts their first bending mode above the band where frames resonate. Every part prints flat in PETG HF, which is tougher and more heat resistant than PLA.

What you can change

Prop size, which sets the wheelbase
Motor mounting pattern and screws
Flight controller stack pattern and board size
Camera width and tilt range
Battery size and strap width
Arm section and standoff height

Specifications

Props: 4 in
Wheelbase: 189 mm
Motors: iFlight XING2 1404, 9 x 9 mm M2
Stack: SpeedyBee F405 Mini stack, 20 x 20 mm
Arm's first bending mode: 256 Hz

Printing

Plates, print hours and filament grams for each Bambu Studio project
Project	Plates	Hours	Grams
4 inch FPV quad frame, PETG HF	3	3.6	107.3
Total	3	3.6	107.3

Times and weights come from the Bambu Studio 02.08.02.61 slice at 0.20 mm layers. Each figure is rounded on its own.

In the room

Credits and licence

The organic arms and camera cage follow the look of Dr. J. Ma's BM Aether 4 (https://makerworld.com/en/models/541413), and its users' reports shaped the bolt-on arms. No file of it is used.