Many thanks to all who have replied.
I thought I'd give you a tip on working with plastic (vinyl) tubing: The easiest way to put holes in it is with a short piece of brass *tubing* just like you would a drill bit. Various diameter tubing is available at most hobby or hardware stores. Just cut a piece about 2 inches long (... errrr this is Australia, make that 5cm long ;-). Put it in a drill and spin the 'cutting' end against some sandpaper to give it a sharp edge. Using it like you would a drill bit you can cut perfect circles through vinyl tubing without distortion. It's quick too. I made 36 connectors for a multicell box kite last weekend in about 10 minutes. I use this method on all my stunt kite fittings. Give it a try....
Thanks for the tip, however 3mm fibreglass does not really need this technique as you do want a good tight fit. But for larger spars such as 6mm dowel (err.. for Americans, 1/4 inch dowel ;-) a 4-5mm hole maker slightly smaller than rod diameter) would be a great help.
Anthony's Addition, 5 March 1997
I have started using a leather hole punch set to the largest hole setting for punching holes in vinal tubing for dowel framed tetras. This works very well though the hole is a little tight at times. It is also quick, and clean and does not require a workbench.
Thanks for the tip.
I saw your plan for the fiberglass tetrahedral using the plastic tubing for the connectors. It was a type of kite that I did not have so I pulled your plan from net and decided to built a 10 cell Tetrahedral using 6mm dowel over the Christmas period. I wanted to have something new for a week long kiting festival-workshop/s that were held down in Tathra (NSW south coast just below Bega). I'm pleased to say I found it easy to make thanks to your ideas and instructions and it flew well - created a lot of interest.
The kite uses a cell size of 50cm covered by ripstop. I created your 4 cell version first and then added another "bottom layer". It flew well in 7-10mph wind and higher. I haven't tried folding the Tetra as I tend to carry kites in two ski bags on a roof rack and hence take the tetra fully apart. With practice I'm getting better at assembly without finding "spare" sticks being left over!!! My wife calls it my puzzle kite.
We publish our club magazine "Flying High" about 6 times a year and I'm being "pressured" to write an article on building the tetrahedral. My intention is to focus on my experience and give reference to your plan. Question:- Before I go ahead do you have any objections to me including references to your plan in the article? I'll send you a couple copies of the magazine when it's published.
Yes you can refer to this plan (and/or use parts of it in the article). I look forward to seeing this artical and may if you do not mind incorperate some of your suggestions into the main plan.
We fall in love at the first sight with the tetraedral in your page, and we build a 40 modules tetraedral, divided in ten modules of four each.
The joint we used was tape, masking tape, and it works very well.
The modules have 75/35 cm steaks and we used colored paper with glue. We transported the kite in the ten separates modules and build it no site (20 minutes work). The wind was 3 to 5 km/hr and the kite was a sensation, very preaty and quite.
Thanks for your idea.
PS: We won a contest with the tetraedral, aproximatly US$150!!, so thanks you again. The credit was yours.
Woo hoo.. the best kite i have ever built and flown and i love the idea of using the hose pipe for joints never thought of that before.. I was using 60cm cells. The newspaper was perfect for the task. I had the rear cross member extended extra wide almost 3xL rather than 2xL it needed it for the ground winds.
It is the most exciting kite I have made, and an immediate success from the construction room floor into the air.
Thank you very much.
Andrew (from Perth Australia)
I've tried to fly it once or twice, and while it flies, it wants to 'hunt' left and right after I get it into the air. Almost to the point of doing a complete 'roll' before righting itself. What I want to know is, is this a symptom of it being too heavy (having been built out of wood dowels), or must it be LARGER (have more cells) to be stable? Also, would decreasing the 'dihedral angle' of the individual cells help fix this problem?
A one cell tetra is definatly unstable as the center of forces and the center of gravity coinside exactly. A 4 cell is borderline stable, as you can see with the way it "rolls" around. A 7 cell tetra (3 cells added to one side so base is 2 cells by 2 cells with three on top -- see Tetra Variations) is even more stable.
The larger a tetra kite is the more stable it becomes. As such my suggestion is give the kite more cells! The more cells a tetra has and the lighter it is the less "roll" and figure '8' movement the kite has!