Kite string - how strong?

by Dru
(Dallas, TX, USA)

Q:

I know almost nothing about flying kites, but have picked a project for my to-be 8 year old's birthday party and need a little help.

I'm having each kid paint a styrofoam plate and am going to assemble a centipede kite (found the project at www.dancingfrog.net/Dancingfrog/centipede.html) Result should be about 20 9" plates, so total length will be about 23' head to tail.

The lady in the article said she used 100# dacron. I'm having a hard time finding that in the local stores. Would 200# be too heavy?

FYI, I live in Dallas. We've had very little wind the last few weeks but it seems to be picking back up again, in the 10-12 mph range. (Early spring was 20-25).

And if we add more plates will I need stronger line?

Thanks so much for your help. The kite should be a big hit at the party, but it will be even more fun if it flys!

Thanks so much!
Dru

P.S. Nice site by the way!

A:

Well Dru, the first thing I did was to crack out the calculator and figure out the total sail area of that kite...

In theory...

Let's see, covert to Metric first :-) A 9" plate is about 23cm across. That's a radius (R) of 11.5cm. Area = Pi x R x R = 3.14 x 11.5 x 11.5 = 415 square centimeters, close enough. With 20 plates, that's 8300 square cm. Or quite a bit less than 1 square meter.

Now, my light wind Rokkaku is somewhat more than 1 square meter, and I always fly it on 50 pound line. Even when wind strength is up a little, into the 'moderate' range.

Not all kites are equal in terms of pulling force, but these are just 'ball-park' figures, and useful enough for this situation.

Recommendation:

So, in anything up to moderate strength winds of say 15mph, I would say any line you can get between 50 and 100 pound breaking strain would be OK. You could even try this Kite Spool - 90 Lb Test from Amazon.

As the wind strength goes up past 15 mph, so will the risk of something breaking. But it could be one of those plates, rather than the line itself which might let go! And if a plate breaks, the kite has just adjusted itself for stronger winds ;-)

200 pound line would be very safe, but it would also result in disappointing performance (low line angles) if winds are barely enough to lift the kite.

More plates, more strain:

And yes, double the number of plates, and you will definitely double the strain on the line! 200 pound line would then work nicely. Can you imagine an awesome 50 plater on 200 pound line...

Hope this helps!