Building a Tetrahedral Kite

Posted by: Scott on: June 25, 2008

• In: Activities | Outdoor | Physical Science | Projects
• 6 Comments

This is a very cool activity. If you look at how this kind of kite is built, you will see it grows like a pyramid. The result is that you have a set number of cells that have to be built to make this work. Here is the link where I got the project in the first place.

http://britton.disted.camosun.bc.ca/tetrakite/tetra.html

Also an NCTM site:  http://illuminations.nctm.org/LessonDetail.aspx?ID=L639

Now for some pointers:

• Think light. Apparently there is a kite season. Good luck finding kite string when it isn’t kite season. I use macramé string I get at AC Moore. The macramé string is strong and inexpensive.
• It helps to precut the strings and the tissue paper. Again, I purchase tissue paper at the dollar store. They have 30 very colorful sheets for … yep, a dollar.
• Rather than tying the ends of the strings together as instructed, I’ve found that it’s easier, quicker, and better if I use a separate small left over pieces of string and just tie the corners together. It’s much easier to get a tight joint and tight connections make for a happier kite.
• I’ve made these kites with 4, 10, and 20 cells. With 4 cells it wouldn’t get off the ground. With 20 cells, only the slightest of winds and we couldn’t keep it on the ground. I like to supersize my science whenever possible.
• Pay careful attention to step 19, creating the bridle. You are going to have a hell of a time making it fly if you don’t put it in the right place.
• I had never seen one of these fly, so I was surprised when I realized they fly upside down. In other words, the point of the pyramid points down. To launch, simply place it on the ground, give the string a slight pull to try to lift the kite onto the point. If there is any wind, the kite will take off into the air.

There is a lot more you can do with this design. The picture on the right is a group effort by a 4th grade class. There is a lot of great information and ideas at their site: http://www.cit.gu.edu.au/~anthony/kites/tetra/straw_plan/

One final point. I could barely get the 20 cell kite through the door. If you are planning on going larger than 20 cells, you might want to plan to build modules and connect them on site, or maybe have a set of double doors to get your monster kite out of the building.

Tags: Flight, Kite, Lift, Tetrahedral Kite