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Box Kite Tension


Box Boy
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I need help concerning humidity(?) and its effect on cellular kites! I have experianced this before but in reverse, I once took one of my cody kites from Oregon to Reno, Nevada, when I got to Reno I had to adjust (loosen) all my tensioners to be able to set the kite up. Recently I have built a Cody here in Arizona, set it up, everything is great. Ship the kite to England and the wood longeron rods look to be curved because they are tensioned to tight causing the side box walls to sag, and when I say sag I mean SAG! This does not make sense to me because there should be more humidity in England than in Arizona which would cause everything to go slack or saggy rather than too tight. Any ideas what might have happened, if you are interested I can supply you with photos.

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Not sue about kite material, however I know tent guys used to need adjusting due to wet or dry.

I wonder if the material has tightened, in effect shrunk along its long sides, thus letting the shorter areas seem to be slack.

Not sure if I explained that very well. Sorry.

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BoxBoy,

Do you have a picture of the end results?

One area you might think about is the differance in expansion/contraction of various materials due to humidity and temperature. A carbon fiber rod does not expand or contract due to humidity, but a wooden dowel will change dimensions. Poly is not as affected by humidity as much as nylon. Thus, a poly sail on a carbon fiber rod frame will not see problems due to humidity as much as a nylon sail on a wooden frame will. Not sure who winds the expansion race with a nylon sail and a wooden dowel ... the wood or the nylon ... but a picture might yield an answer.

Going off to a weekend festival right now ...

Cheers,

Tom

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Keep in mind I have zero knowledge about Cody kites, add salt as nessasary.

In the after photo it looks like the wood dowel has warped, and/or the stays/lines to the wing tip are too tight. Is there a reason for using dowel instead of carbon tube on the four corners?

Beautiful kite by the way....... ;)

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Can't verify expansion/contraction of the cloth but I can talk about the wood dowels.

Wood expands and contracts according to the relative humidity of the surrounding air It begins with the moisture content of the wood at the time it's being worked. Then when exposed to less relative humidity it'll shrink and expand when exposed to more.

As a master cabinetmaker I always checked the moisture content of hardwood shipments and would refuse anything over 10%. I could then more accurately predict how and where the wood would move under different circumstances. The environment within which the piece is made is very important too. For example, in the winter if the relative humidity outside at 25 deg is 40% and the piece is made inside in a heated environment at 65 deg the relative humidity might be 0% and whatever moisture in the wood would leave it.

Also the direction the grain runs dictates how the piece of wood will warp along with knots (beginning or end of one).

Take a short piece of the wood, weigh it the stick it in an oven at 140 deg for a couple of hours. Weigh it and you'll be able to calculate the moisture content.

Hope this helps,

Charlie

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Just LOVE that Welsh Dragon.

Stupid question maybe. Are you SURE it is assembled correctly.

Difficult to tell with the perspectives of the pictures. Looks like the dowel is curved and the lines tight as Walt suggested.

In the B4 picture it looks like the lines may be slightly looser. Also if there is more humidity with the kite now is it possible the lines have shrunk?

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Thanks for the input so far, I was thinking about warp but then I had the person with the remove the diagonal rods and the wood rods straightened out (since I was not there I don't know how much they straightened). I am thinking that the change in humidity from Arizona to UK must have had something to do with it but my experiance has been that a kite gets tighter as you go from more humidity to less not the other way around. When I notch wood dowel I always try to notch with the grain. The reason why I use wood is because I believe it looks best on a cody and it is easy to replace when fiberglass is not available. I never use carbon rods, only fiberglass tube. On a cody I like to have some weight on the kite which I believe adds some stability in higher winds

Again thanks for the ideas, this has never been a problem when building and shipping a kite from Oregon to anyplace else.

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If you have never had a problem B4 that would lead me to think it might be a problem with assembly?

How familiar is the person who has the kite with setting it up?

Not familiar with Codys, looking at this one though it looks great.

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This is all getting very strange! The person with the kite does have another cody so he does know something about setting the kite up. My kites are a little more advanced than most store bought codys so this could have been some of the trouble, almost everyone that has one of my codys I have been able to spend a little one on one time with or they know someone else that has one of my kites. After the person has had the kite now for a few days and after several emails back and forth the kite is now coming togather the way it should, everything is looking good! Now I am wondering what happened weather wise during the shipping of the kite, after a few days of being out of the package it is looking the way it should. :confused!:

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As long as you think the person with the kite didnt mess with your settings to cause the sagging, I would think it has got over its jet lag and is ready to go.

Could well have been an issue with humidity or weather. Now that it has got used to the British, or maybe looking at the Dragon Welsh (it always rains in Wales, well not always but why do you think it is so Green?)

As I said I love the kite.

Tell you what, make another one, send it to me, I will set it up and we will see if the same thing happens. ;)

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... Tell you what, make another one, send it to me, I will set it up and we will see if the same thing happens. ;)

In most of our north western parks we have signs that say "Don't Feed the Bears" ... Boxboy, that seems appropriate here. Darn things become terrible pests if you start sending them kites feeding them.

Glad the problem is solved. A quick look at the picture suggests that it is an adjustment problem rather than humidity/temp problem.

The kite is really neat ... do you make other kites? Pictures of those kites? A web page? Please do share!

Cheers,

Tom

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http://www.flickr.com/photos/34405377@N03/ If I did this right this link will take you to my photos on Flickr and you can take a look at some of my codys. Thank you for all the very kind words about the kites. I found out that shipping a cody from here in the states to the UK costs around $150. add $400. for the price on the kite and ... put that under the sign that says "Do Not Feed The Bears" and we should have any problems with the UK taken care of ... right??

On my Extended Wing codys there are 10 adjustable wing lines, with sliding knots, and another 6 adjustable lines for the Top Sail, it is amazing how much you can distort the kite itself if any of these lines are adjusted too tight.

I have been building and selling codys since around 1995 so I could not tell you how many I have built but I don't believe I have ever built any two exactly alike. Again thank you for the kind words, there will be one of my smaller codys available in the members raffle soon, the kite is built and I just have to get back to Oregon, put rods and a bridle put on it and it is ready to go.

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Rick,

Those really are great looking kites.

I'm working on a six-kite stack of half scale rev-like kites. I'm really astonished with the work and decisions that go into making a simple quad kite. Your kites look way beyond the simple ... I'm very impressed!!

Thanks for sharing,

Tom

PS ... At Kite Party, I asked and received Ben's permission to build the half scale kites.

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My hat is always off to anyone who will take the time to build themselves a kite, an extra "Way to Go" to anyone that takes the time to build a kite well and there is never anything like the pleasure a kite builder gets after building that first kite and seeing it in the sky. The one other pleasure a kite builder gets is to build a kite and then walk onto the flying field and seeing someone else flying a kite you have built and then sold to that person, no need to say a word just sit back and enjoy watching that person fly the kite you built for him or her.

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My hat is always off to anyone who will take ... the time to build a kite well and there is never anything like the pleasure a kite builder gets after building that first kite and seeing it in the sky.

You're right, you couldn't get the smile off my face last night. Talked the 180GO! squad members into flying the "Half Pint" quad ... approximately 2/3 the size of a REV II. If you think a REV II is a little quick, this size kite is like a bumble bee on steroids. It took about two minutes for each of them to stop sucking air and slow down their handle movements. But then, they were able to fly it quite well. Not bad when I was afraid the darn thing wouldn't even fly.

The one other pleasure a kite builder gets is to build a kite and then walk onto the flying field and seeing someone else flying a kite you have built and then sold to that person, no need to say a word just sit back and enjoy watching that person fly the kite you built for him or her.

Can't do with this kite. That was the promise to Ben ... not for sale! Besides, if I only made minimum wage, no one could afford to pay for a Half Pint. The real turn on is the research, the planning and the futzing around making a kite. My hat's off to anyone who can make a living manufacturing and selling kites ... not an easy occupation.

Cheers,

Tom

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Box Boy,

Beautiful kites. You definitely have a talent for building Cody's.

I built 4 Hargraves Box kites, 2 full size and 2 half size using 1.5 wt ripstop and 15 mm and 10 mm fg tube respectively. Every time I reassemble a kite on field they fly differently unless I put the diagonal brace spars in the same position and use the same tension on the vertical cell tensioners. The air temp and sunshine does affect the ripstop but I guess humidity will affect cotton based fibres more.

Bob Moore

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Trying to build, sell and make a living as a kite builder, especially in single line, I would think is near impossible, about 3 years ago I went into a kite store and found the same size cody as I build the kite is coming out of China and selling for about $40. mine sell for $400. The price of $40. would just cover my cost of materials and starting my sewing machine. I would love to see photos of the Hargraves, they are fantastic kites in the sky! Years ago a friend, Jerry Sinotte (not sure of the spelling of his name) built a large Hargrave kite and used all wood framing, I sure wish I had a photo of that kite.

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  • 1 month later...

Trying to build, sell and make a living as a kite builder, especially in single line, I would think is near impossible, about 3 years ago I went into a kite store and found the same size cody as I build the kite is coming out of China and selling for about $40. mine sell for $400. The price of $40. would just cover my cost of materials and starting my sewing machine. I would love to see photos of the Hargraves, they are fantastic kites in the sky! Years ago a friend, Jerry Sinotte (not sure of the spelling of his name) built a large Hargrave kite and used all wood framing, I sure wish I had a photo of that kite.

Here are some links to Hargraves replicas:

http://www.kites.org/aka/hargrave/royal_park/leneke.htm

http://www.classic-kites.org/04_index.html

http://www.ctie.monash.edu.au/hargrave/casalboni_hargrave.html

Here is an image of one of my Hargraves.

http://kitelife.com/forum/index.php?app=gallery&module=images&section=viewimage&img=3080

Bob Moore

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Hi Rick,

I realize I'm coming in a bit late here.

You said you shipped the kite.

The cargo areas on aircraft are generally pressurized to 10,000 feet, and not heated so they can get very cold.

Freight also can end up sitting in airfreight containers on the tarmac in the sun in Dallas, and get very, very hot.

Humidity, in either of those areas is anybody's guess.

Your kite returning to normal after a while points at something harsh happening to it on the way.

Glad it cured itself!

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