Carbon Fibre Tube Quadcopter - Kraken Pod by MantleQuads

Last crawled date: 3 years ago

UPDATE: Both V1 tube frames have been broken due to the carbon tubes not being properly secured and reinforced. I am working on a second revision that will use two small carbon plates to reinforce the arms, rather than relying on a big blob of epoxy.
Inspired by the Bexamous tube frame: https://imgur.com/a/hEevI
Final frame weights:
5" 200 size - 43g with a 2mm Kraken pod (31g without)
6" 230 size - 55g with a 3mm Kraken pod (34g without)
To make a frame you will need:
4x 10mm_tube_16mm_mount (the part the motors mount on to)
1x 10mm_tube_Kraken template (this part is used as a template for drilling the board and pod holes and filing the notch)
10mm OD, 8mm ID carbon fibre tube, length of your choosing. I get mine here: http://www.ebay.com.au/itm/1Pc-Roll-Wrapped-Carbon-Fiber-Tube-3K-8mm-x-10mm-X-500mm-For-Multicopter-DIY-/131665162489?hash=item1ea7daf0f9:g:i3MAAOSwNphWXWZJ
Epoxy, I used 5 minute epoxy.
Optionally, a Kraken pod, I find the 3mm pod to be indestructible but the thinner pods are much lighter. I'm currently working on my own TPU pod that will fit a 50x50mm mounting pattern. https://boltrc.com.au/index.php?id_product=162&controller=product&search_query=kraken+pod&results=15
How to put it all together: (Repeat steps 1,2,3,4. You will need to make two tubes)
NOTE: Carbon fibre dust is not good, avoid using rotary tools such as a dremel tool because it will throw dust in the air. A drill, hacksaw and a file are all that will be needed for the build and are all safe to use as long as the carbon is kept wet. I cut and drill my carbon outside spraying the tool and carbon tube with water frequently.
Tools:
Hacksaw
Drill
File
Water proof fine sanding paper (optional)

Measure
Measure a section of carbon tube, wrap the area to be cut with masking tape. For reference, I use two 250mm long tubes for a 6" and 220mm for a 5", both fitting a Kraken pod.


Cut
Cut the tubing as desired with a hacksaw, keeping the tube and saw wet so no carbon particles escape. You may have to roll the tube around to make the cut. If the end of the tube is left rough or uneven wet the sand paper and smooth out the tip of the carbon tube.


Drilling
Slide the template block on to a tube, lining the middle of the notch up with the centre of the tube. Place a motor mount on each end of the tube, ensuring that the end of the tube is level with the end of the motor mount. Ensure that both mounts and the template are correctly placed, you don't want misaligned holes. Drill a small pilot hole through all holes on one side of the tube, I use a 1/16 size bit. Repeat on the other side and follow up with a larger drill bit to widen the original holes so that they can all fit a M3 bolt. (Using a pilot hole minimises splitting of the carbon.) Wet the tube and drill bits as required.


Filing
For this task I use a 4mm wide file that is about 200mm long. Wet the notch and file and begin to wear at the exposed carbon in the notch with the side of the file. remove all carbon from the notch and attempt to make the edges as smooth and straight as possible.

Assembly
Remove the template and place all motor mounts on the ends of each tube, lined up with the holes. Notch the two carbon pieces together and check they will fit smoothly and correctly. Begin to mix the epoxy. (I use a broken prop for this, actually very good for scooping up a little bit of epoxy and applying it.) Coat the edges of the exposed notch on each tube with epoxy, Apply epoxy to the gap between arms at the centre of the frame as well as the top and bottom of where the notches meet. (Bexamous' guide has pictures detailing this process and shows how much epoxy should be used) To make sure the frame comes out straight I like to flip it over so the mounting surface of the motor mounts is upside down, then I screw on a Kraken pod to make sure it holds a good X shape. Allow the epoxy to cure for at least about 12 hours, preferably in a warm dry place.