Tuesday, March 23, 2010

My Bamboo Skewer Box Kite

I haven't built anything creative in quite a while. I used to be famous at my school for my creations. I've built all sorts of stuff from everyday, low-cost materials. Probably the most sophisticated thing I've built is my wind tunnel which really works and is very precise.

Wednesday at school we are having our "Spring Fling" and I am on the kite making team, so I worked with the elementary students on making simple kites.

Back in kite mode got me thinking...

Box kites: Then...I remember my brother having a box kite and I always thought it was cool. I first tried to build one from scratch about 30 years ago, but it didn't work out too well.

Now...On the Fausto Trail on El Morro is a frame to an old box kite that somehow ended up there. Who knows how long its been there, but each time I ride past it, I look at it noting its construction. It is very strong for being around as long as it has, so I've tried to duplicate the design using bamboo skewers used for kabobs.

The prototype...
Yesterday I built a box kite from drinking straws just to see if I could. I built it in about 45 minutes and it worked okay until the drinking straws started bending from the gusts of wind. I decided I could use the same dimensions and build one out of sturdier bamboo skewers. Here's how I did it:

1. I cut off the pointy ends of 12 skewers so each stick is 26 cm.

2. To make the long sticks, I overlapped them about 2 cm for a length of about 50 cm. They were glued and lashed together with cotton string.

3. The cross pieces are also 26 cm, so they cross at 13 cm. I made a little notch at 13 cm then glued and lashed them together with the cotton string, and lathered on more white glue.

4. The long sticks were notched at 6.5 cm from each end and the crossed pieces were glued onto the long pieces. The glue was allow to dry, then reinforced with a paper/white glue gussets.

5. The cross pieces make little triangle with legs each 13 cm long. The string which wraps around the frame for stiffness and strength creates a hypotenuse of 18.5 cm on each side. The perimeter around the frame is about 74 cm. The string should be cut at 1 m in length so you can tie it off.

6. The perimeter coincidentally was the was right sized for the little grocery bag I was using without having to cut and retape together. The width of the plastic is 13 cm. I just slipped the plastic over the frame for a snug fit. I used stick glue to glue the plastic on to the frame and string guys. I just eyeballed the width and it seemed right.

7. The bridal is about 75 cm in length tied to two corners; one top, one bottom.

Total weight is probably about 25 grams. I need to confirm that tomorrow.

Anyway...it flys!


Randy Salars said...

Simple and elegant. Great job!

Gunnar Berg said...

When I was going through my kite flying phase in my late twenties I made a 8' tall triangular box kite with a wing. The frame was combination of aluminum tubing and white oak, with nylon tent fabric for the lifting surfaces. I know that sounds heavy, but at that size struts kept failing. I tied a safety cable to the pickup bumper. It was damned near a man lifter. Probably would have failed your test though

MyBestKiteGuy said...

Stumbled across your Skewer Box design via image search today. Seems we have 'independently invented' the concept!

See http://www.my-best-kite.com/how-to-build-a-box-kite.html

I like your gussets approach for its simplicity.