Carbon fibre is very strong and very light. Everyone says so. We wanted to know why, so we made a video about it.
What is in it
Carbon fibre starts as a polymer thread, polyacrylonitrile. It is baked at over 1000 degrees without oxygen until almost only carbon is left, lined up in sheets along the fibre. One fibre is about 7 micrometres thick. Thousands are bundled into a tow, woven into fabric, soaked in epoxy, stacked and cured into the plates our frames are cut from.
Carbon against aluminium. A woven carbon plate and aluminium are about equally stiff, around 70 GPa. But carbon weighs 1.6 g per cubic centimetre against 2.7 for aluminium. For the same weight a carbon plate is about 1.7 times thicker, and bending stiffness goes with thickness cubed: almost five times stiffer in bending.
Why one part of the OpenFrame is aluminium anyway. Aluminium bends and stays bent; carbon stays elastic until it snaps. For the camera mount we want a part that deforms in a hard crash instead of breaking.
Then the crash test. Full throttle, straight up, into the underside of a motorway bridge. The battery caught fire and half the electronics died. The frame shows no damage you can see, and that is exactly the catch: carbon can delaminate on the inside while the outside looks perfect. The video shows the simple check, tapping it with a coin.
With Marcel Bruijn, composites expert, and Thomas, our CAD engineer.
The OpenFrame
The 5 inch and 3 inch OpenFrame are open source: download the files and cut one yourself (5 inch, 3 inch), or preorder one cut from the same plates.
Preorders pay for the production run. The price steps up as units come in: the first 100 of each frame were 20% off retail, units 101 to 250 are 10% off, after that it is retail. The run ships by 31 March 2027 if the target is reached by 15 December 2026; if it is not, you choose a full refund or to wait.
Come see the lab
We build in the High Tech Lab at maakleerplek, Stapelhuisstraat 15, Leuven. Open lab on Thursday 18:00 to 22:00 and Saturday 14:00 to 18:00. Plan a visit