16 mm carbon fibre tube
The best stiffness-per-gram available without machining. Roll-wrapped carbon tube is what quadcopter arms and lightweight robot links are made from.
The role it plays
Structure is a stiffness-per-gram competition. Aluminium extrusion is cheap and modular but its bolted joints creep. Carbon is stiffer per gram and fails without warning. Printed parts win on geometry freedom and lose on layer adhesion. Match the material to the load path, never the other way round.
Typical use: Drone arms, arm links, lightweight booms.
What the numbers actually mean
The headline figure is 16 mm (outer diameter), with 1 – 2 mm as the next most load-bearing number (wall). At $25 in the structure tier it sits cheap enough to prototype with and replace without regret, which is the correct way to learn a new subsystem.
How it compares
Same subsystem, closest alternatives. The primary spec column is usually the one that decides it.
| Part | Price | Primary spec | Second spec |
|---|---|---|---|
| 16 mm carbon fibre tubeComposite tube | $25 | 16 mm | 1 – 2 mm |
| 2020 T-slot extrusionStructural profile | $8 | 20 × 20 mm | 6 mm T-slot |
| 4040 T-slot extrusionStructural profile | $16 | 40 × 40 mm | 8 mm T-slot |
| PA-CF printed structural parts3D-printed composite | $40 | ~70 – 100 MPa (depends on print) | ~150 °C (annealed) |
Where it shows up
Platforms in this atlas that use something in this class: 5-inch FPV freestyle quad.