Hi, I bought these very cheap hobbyking rectangular carbon tubes. I made this not so serious experiment with them as they could potentially be great to build your own multicopter frames. Tridge, by the way, used those recently in his quadplane build he posted about on diydrones.
And, this is a not so serious contribution to coming Easter chickens...
Enjoy Easter everyone!
Hugues
Comments
thanks for doing this! Much more comprehensive testing than I did.
When I bought the tubes I tested they could handle 2x the maximum expected force by doing a similar test to your "body mass" test but with lead diving weights. Grant and I held down one end on a table and then loaded up the other end with diving weights. As it didn't show any signs of undue stress and didn't bend much we thought they would be OK for the quadplane we were building.
In the crash of our first quadplane the CF tubes were not damaged at all, but the epoxy bonds of the CF tubes to the CF flat plates on the underside of the wings did give way. On one side the two CF tubes also came apart from one another (again, the epoxy bond gave way under the shock of the crash).
This was actually quite lucky as I think the epoxy giving way reduced the damage to the wings. The wings survived with only minimal damage on one side (a leading edge crack which is fixable). If the epoxy had held I think it would have done a lot more damage.
Happy easter!
Hi Vladimir, I have been buying very happily from Rockwest, quality and finish is absolutely excellent, but selection is somewhat limited.
By carefully selecting product desired prices are better than most other high end places like Dragon Plate.
I mostly use thin wall round tubing and in standard sizes.
The square stuff laid up not pultruded is seriously expensive, but if it is out in the air stream (worse the down wash, its air resistance is twice what round is for same outer dimension, and it is not resilient so I use round almost exclusively.
Tubes vs Squares
Any thoughts as to which is better? I can't help but think squares are easier to use with 3D printed parts for easier, more accurate alignment and less chance of slippage or rotation during flight
Chiken with potatoes at night? :D
Thank's for share the test Hugues
Personally, I order from alibaba. The two problems are minimum order quantities (depends on seller) and shipping fees.
I found Dragon Plate to be more expensive, although I'm sure their quality is sky-high. Also, their metric selection was lacking last time I checked.
Pultruded CF tube is generally worse than Fiberglass tube especially G10.
Even though generally speaking the G10 Flexes a bit more it is a lot more resilient and stronger in the event of a mishap.
Those pultruded tubes snap and crumble at any type of hard impact, I really don't think they are the correct choice for any use.
Rockwest composites and Dragon Plate provide top quality CF tubing which I use and I have other on my links as well at my Drones Are Fun links page:
http://dronesarefun.com/InformationAndLinks.html
If you really want to use CF tube, the good stuff is actually worth it, if you want to spend less or have something that will survive accidents better use G10.
Thanks.
I was about to buy some. (Probably still will).
I kind of assumed the twill might be for show (it's Hobby King). But pultruded's not the end of the world.
They make a smaller-cross-section square tube and a round tube that nests perfectly inside the square one (because it has a cylindrical inside cavity) - it's very handy if you need a small, very light 'sliding rail'.
I also use a lot of their square aluminum tube (12 x 12 and 15 x 15 mm). Thin walls, but ribbed along the inside for stiffening. Dirt cheap, and no disappointments yet.
For the serious stuff, I might go with Dragon Plate in the US, or such.
George
A while back I bought a 12mm x 500mm carbon tube (circular, not square) from hobbyking to compare against the same size tubes from a carbon fiber supplier. HK's tube flexed way more (5x?), and weighed more, too.
Ben, ok lol. I guess they do care those damn chickens then!
Rob, thx. Yes they are great for prototyping at low cost. I'm currently building an anti-vibration camera mount with these tubes. I'll post some pictures when done.
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