Many thanks to all who have replied.
In most kite books they work with greater base cells (i.e. unit cell as big as your 4 cell module. I'm wondering which is giving the best results: same surface with 4 small cell surfaces (your's) or same surface with one cell surface. I mean; with a given kite dimension many small sails, or less but greater sails. Could this have any influence on stability of the kite at greater wind speeds for example? I must say that at least visually the kite looks great and fine with small sails, even if it's more work... Is there any rule to determine what's best?
Even by strenthening the straw extremities with tape they began to alter after an afternoon of flying time and I will look for some plastic tubes which are much more resistent...but too heavy perhaps...
I used one fixing point at the front corner and worked well.
We used plastic drinking straws, nylon stranded kite string, and transparent plastic gift wrap. We hope that the plastic wrap holds up. Basically the construction went without a hitch. All in all it took about 4 hours of our labour to get it done.
We had moderate steady winds when we flew the kite. It did not do well when we tried it on Sunday in light wind. We noticed that the kite need a bit of balancing as it seem to list a bit. We had attached the kite string at the front of the kite rather than making a bridle. All in all it was great fun.
One comment on the small basic tetrahedral is that it did not fly as well as our larger one. It tended to twirl as she tried to get it up in the air. Tena and I had made it before doing the larger one.
Anthony Replies:- The metalized wrapping foil is called mylar and is very very thin, tough, and light. It is what I used. I am glad you liked the plan. I hope your kite still folds flat!
According to various books, the more cells one adds, the more stable this kite should become. One reference I used (from Penguin Books) said that Bell's original design called for the cells to be over ten inches on a side before it would fly as a one-cell kite. This would seem to be correct, as previous versions with smaller straws refused to fly.
Regardless, it looks beautiful when it flies. -- Peter Eng
Anthony Replies:- Great I am glad you liked the result. My own experence is that the kites stability in a 4 cell form also reflects greatly on just how turbulent the wind is. The smaller kites love a sea breeze coming directly off the water, but become unstable (unless you increase it to a 16 cell version, if the wind has to come across any appreciable amout of land (with its trees, houses etc..) making the wind turbulent.
The kite was a 16 cell version and flew well in the 10-15 mph winds. The only variation we made was the straw connection. We used crazy glue, however, we reinforced each joint with nylon ribbed packaging tape.
I must admit that I was somewhat apprehensive about this project but it turned out fine and the kids enjoyed building the kite. It took about four hours of class time (actually some aren't finished yet but we will be finishing them tomorrow. However one of the kids finished and returned to excitedly inform me that it "...really flies". She was delighted and, of course so was I.
Now if we can just get a decent wind in the school yard tomorrow when we finish the rest it should make quite a sight with twenty four kites all flying at once. Thanks for the idea! It was great fun and I look forward to trying this one again next year.
Sincerely, Bill Birtch
Reply: That is great! You may also like to try a `group effort' and join them together into a large super tetra! Good luck with the winds :-) -- Anthony
The idea packet will be spiral bounded, distributed to teachers who go to the workshop and to school sites. The kite plans are just a bit different to your plan....
You would need 4 pieces of thread cut approx. 40 inches an 8 pieces cut approximately 16 inches. Thread three straws on a 40 in. thread, and tie as a triangle, leaving a 4 in and 12 in end.
Loop a 16 in thread at the two vertices that don't have the extra thread, tie leaving 4 in ends. Place a straw along these long 12 inch threads that are at each vertex and tie two of them leaving no slack and then tie the third. Now you have a tetrahedron. Yes, I've not been very specific but if you picture it in your mind, where you tied those three straws, you will have three little threads hanging out; let that be your top vertex. Do four more tetrahedra, and you can then tie them more easily.
Reply: That is a nice solution, though my method is to build four tetrahedrals at a time as a single unit. In any case your method will work fine. The result will be a stronger and slightly heavier tetrahedral which will not fold flat. However if the individual cells are seperable, you can stack the tetra cells within each other. Making a small though 3 dimensional stack of cells for transport. Please let me know what happens with this teaching unit plan. -- Anthony
You might find it interesting. The students have a great time flying
them. They really fly well. I haven't included the instructions
for the bridle yet. Thanks for an interesting site.
In the end we recorded an item in the studio showing how to make a 16-cell kite, opting for the simplest approach possible (ie. no elastic). Last Monday was the moment of truth, as we attempted to fly our kite. You won't be surprised to hear that it flew beautifully.
Anyway... the kite grew, and we ended up with a 64-cell Sierpinski. Since the wind was light (12kts), the only reinforcement I added was a length of 4mm dowel zip-tied down the keel. The kite was tied together with 50lb line, and bridled with the same line between the top and centre of the keel. I flew off 150lb sleeved line, which was serious overkill but happened to be kicking around. The 150lb was slip-knotted to the bridle so the kite could, to some extent, find its own angle.
The result was a 5-foot high monster. I didn't try ground launching it, since it was *very* fragile on the ground. Instead I held it by the bridle point, flicked it skyward, and let go when it seemed happy.
Well... it flew. Boy, did it fly. It pulled hard enough that I worried about the 50lb line giving out. It was rock-solid stable, and flew at a considerably higher angle than the 16-cell. After an hour airborne we finally brought it down. While some of the straw ends had been ripped by the string, most were intact.
Sadly I've nowhere to store such a monster, so I left it with our hosts at the aerodrome (a display company called Aerosuperbatics, who launch aircraft off car roofs for kicks, and do this: http://www.crunchie.co.uk/). Hence, it's accurate to say that the kite is now hangared at RFC Rendcomb airfield, Cirencester, England. :)
NOTE: The TV program was called ``The Big Bang'' and isn't broadcast outside the UK, but FYI the series will be shown from 31st March, on Mondays at 4:45, ITV (UK national)
Associate Producer, The Big Bang.
Yorkshire Television, Leeds.
PS: I hope others are encouraged to go completely mental and spend days making a kite that, until the last minute, feels like it'll be torn apart in the slightest gust :)
I made my kite rigid, but made the 4-cell to 4-cell in such a way that I could take it apart, so I have 4 large (not really that big) sections sitting in my room right now. I made the other connections using superglue (cynoacrylate. . . medium consistancy, gap filling) and straw pieces to hold them together (and to have something to glue). I used lightweight cheap plastic wrap as the covering. . . it seems to be pretty strong. Tape (really clear tape) holds the covering onto the frame.
Assembly went relatively easily, but I know I won't be able to collapse it to store it. I don't mind though, it kind of adds to my room.
Ok, the "Flying Greenhouse" flew! The kite was extremely lightweight, so, when I walked out into the gust 10 mph winds, I was worried about amassing a pile of distorted, shapless plastic. . . luckily, that didn't exactly happen. . .
Some of the taped joints ended up being too weak, and they temporarily pulled loose, but were easily fixed (bring extra supplies!). I was flying in strong, gusty winds, FAR from ideal, I'm sure. The wind would blow 10+ mph, then it would die down to nothing. we got some pictures, just have to get them developed). . . unfortunately, when the wind stopped one time, the kite was about 10' up, and it dropped down right on one of the points and split a straw while pulling some plastic covering loose. Fortunately, the damage wasn't really that significant, so I just flew it some more.
All in all, this kite was and is a wonderful experience. . . I plan on fixing it sometime, but I have schoolwork to do right now. I'm not quite sure how I'm going to fix the split straw yet, but it will be fixed. Right now, it is sitting up high in the corner masquerading as a piece of modern art (or something). I think that plastic wrap is a good covering because it is waterproof and it's quite durable. I'll send in pictures as soon as I get the film developed and the pictures scanned.
Thanks for the great plans!
I made 4 of your 4 cell type and attached them together with more of the straw inside a straw joints bonded with superglue. I built it to be completely collapsable with no struts on the back of any of the cells except the trailing edge. It was a bit to flexable and had a tendancy to lean a bit. I put the trailing edges back on the leading sets of cells and it did MUCH better, but required more wind.
I can't wait to build a more permenant one of ripstop and dowels. I will likely go straight to a 16 cell there as well. The wind in Iowa is too turbulant to go with anything less stable.
At this point I had found a bunch of ballon stick (intended for your el'cheapo diamond plans) which works wonderfully as joint material (2.5-3cm). It has the perfect diameter for the straws I'm using and is very light and strong. I've built 2 more 16 & 20 versions from individual cells jointed with the ballon stick and it works great, and has flown for hours without failure. I'm very pleased.
These kites are fun to make. I gave a couple of the folding 4 cell kites as gifts, and I have requests for 2 more. Since I have plenty of room for storage (hanging from the ceiling in my garage) I have found the larger models benefit from indivdual cell construction. I reinforce the joints with wound string and super glue, sort of like fishing rods. I have used 1/8th inch dowel to reinforce the center spans on the larger kites, superglued into the straws. You have to be careful, keep it symetrical, and not to much for the weight.
I've bought the tetralite book. I intend to build a more permanent model but I've had some difficulty finding the materials called for. Meanwhile, my wife and I fly the tissue and straw kites nearly everyday.
Thanks. Jeff Hittman
I've also built a 34 cell (7×3×3) using straws. It really has some lift and quite some pull. looks nice in the sky too.
The Berkeley Kite Festival was a lot of fun. This was my first festival although I have flown my kites with large groups of other fliers. I met a fellow who had built a tetra kite using ballon stick and colored cellophane.
I have made my own page and tinkered with the directions a bit. We use this plan for kids in groups of 56 to make kites. This year a group of kids got together and make a kite with 80 cells!!!
Ron Gulley, Ford Middle School, Brook Park, Ohio USA
I ran some dowels down the outside edges of the tetra for stability and to hold the four, 4-cell smaller teras together. I found some which fitted well enough at the local hardware store that I was able to hold the kite together without glue or any other hardware -- friction of the straws over the dowels is enough to hold it together. If I want, I can dissassemble the 16 cell into its four parts pretty easily. Additional weight was minimal, but was quite a bit stronger. Cost was about 25 cents for each dowel, which were cut to length with a pair of wire cutters.
Left over christmas cellophone (which is also available cheaply as wrapping paper in up to 100' rolls) was the wing material. Worked fine, and was just scotch taped into place. The translucent brightly colored cellophane looked good, as well as being moderately easy to handle (use sharp scissors since it's pretty slippery stuff).
Cost for the kite was less than $4.00 (two 50-straw packs of drinking straws at $1 each from the grocery store, 5 dowels at $0.25 each, plus left over cellophane and string. With all new materials you could probably do it for less than $20, assuming the biggest cost was in the cellophane -- a 20" by 100' roll should be less than $20 and is enough for *several* kites. (www.papermart.com for prices).
Instead of a kite that will fold flat, I used drinking straws and hot melt glue at the joints.
The result was a very strong structure that I combined ino a sixteen cell kite.
I am able to get the kite out of the house, but probably wont be able to if I make it much larger.
I used 7 inch straws and made each side longer by forcing one into another. I ended up with straw sides about twelve inches long.
I used large plastic bags obtained from my local supermarket. The store had a supply of red and white bags remaining from Christmas. The cashier was gracious enough to give me several of each color.
The kite fliies very well.
Thanks for your interest.
Basically the result of this feedback, and my own findings when I built a version (before creating this plan), was that for tetrahedrals to work they have to be at least 1 meter per side when all the cells are joined or the kite does twirl and be unstable. IE: you really have to create a 16 cell version using this plan.
I also recommend you look at the more permenate and robust tetrahedral kite which you can build out of dowel or fibreglass spars.
-- Anthony Thyssen.