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msyed



Joined: 27 Aug 2004
Posts: 4

PostPosted: Fri Aug 27, 2004 4:25 pm    Post subject: Question about graphite_rods, types of Graphite Reply with quote

I was just making a list of items parts, measurements etc (basic blue prints and stuff i need b4 sewing). And i came to the topic of Graphite rods..

Now making kites seemed fairly inexpensive till that point Razz or am i missing something?

Can someone explain the following terms to me?
Pultruded
Wrapped
Solid (well duh i guess, solid is solid Carbon)
with respect to graphit rods.

2nd. Avia and SkyShark two makers of rods that are well known--strengths and weaknesses or there arent any ?

3rd. How do you know what diameter rods to order, what weight, and im guessing you can order rods only in set sizes? i.e. 32.5" size of rod.

4th Ive looked through sooooooo many different rods, now my heads spinning with names and descriptions, and many sound the same!
Are there certain types of rods that people use in general for your regular freestyle dual line (made to fly in moderate winds? 3-4 mph +)?

Thanks
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Progcraft
Kitebuilder of the Year 2004
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Joined: 29 Sep 2003
Posts: 2559
Location: Calgary, AB, Canada

PostPosted: Fri Aug 27, 2004 4:50 pm    Post subject: Reply with quote

Those are all very good questions. But alas, I have no answers.
But, there is info available.
Here: http://www.kitebuilder.com/inventory/spargrap.htm
Here: http://www.nic.fi/~sos/spars/spars.htm
Here: http://www.kitebuilder.com/techsheets/rokkaku.htm
Here: http://www.kitebuilder.com/forums/viewtopic.php?t=414
Here: http://www.kitebuilder.com/forums/viewtopic.php?t=615

I hope something there can help.

P.
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Spence602



Joined: 16 Sep 2003
Posts: 475
Location: USA TX Houston

PostPosted: Fri Aug 27, 2004 11:01 pm    Post subject: Reply with quote

msyed,

You sound just like I sounded a few years ago - adrift in a sea of manufacturers names and numbers and how they all relate to one another. Shocked Confused And that's just the tubes/rods. Then there's the nocks, c-clips, spreader connectors, ferrels, center tee's, End Caps, etc. and what fits on what. Whew!

Just keep asking questions! Very Happy

Here is another spar chart with relative strengths and weights. It's a little dated (there are SkyShark P-90's (10.5 grams) and P-400's (21 grams) out now).

Here is also some more info on Avia rods, and here is more info about Skyshark tubes.

1) I know KiteSquid can wax eloquently on the subtle (and not so subtle) differences in Pultruded and Wrapped. He can probably point you to a place where he's already explained it.
2) Neither manufacturer is better - each tube/rod has its own place.
3) If you're building from a plan, it'll probably have recommended spars. If not, it's whatever you want. Weight vs strength (vs availability vs cost vs accessibility!)
4) It all depends. I've seen kites for 3-4MPH with .196 CFR (solid rod), some with P-100's, some with mixed G-Force tubes, and some with 6mm/.230 spines and the rest Excel tubes, etc.

Personally, I started out building a freestyle stunt kite with .230 tubes all around. Since that time, I've used G-Force, Excel, Skysharks P-xxx and tapered, Structil, and other Avia tubes/rods. I still like the feel of .230/.240 Avia.

HTH
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msyed



Joined: 27 Aug 2004
Posts: 4

PostPosted: Sat Aug 28, 2004 11:37 pm    Post subject: Reply with quote

appreciate the input! yah, and spars seem to be the most expensive part too
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Stan



Joined: 18 Nov 2003
Posts: 759
Location: San Diego

PostPosted: Sun Aug 29, 2004 1:09 pm    Post subject: Reply with quote

To grossly generalize, I'd guess that 6mm or 2300 pultruded spars are the most versatile and economical spars to start out with. Smaller spars and rods will suit UL kites, and fancier kites can be sparred with wrapped spars to get more stiffness at a lighter weight. It all depends on the kite, and after you make a few, changing incrementally to other sizes will show their strengths and weaknesses.
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KiteSquid
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Joined: 29 Aug 2003
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PostPosted: Mon Aug 30, 2004 8:03 am    Post subject: Re: Question about graphite_rods Reply with quote

msyed wrote:

Now making kites seemed fairly inexpensive till that point Razz or am i missing something?


Nope, you found where all my kite building $$$$ go to!!!!!!

msyed wrote:
Can someone explain the following terms to me?


Sure..

msyed wrote:

Pultruded


A process were the Carbon fiber reinforeced structure is made by both Pulling and Extrudign takes place. The manufacturer selects the number of and type of Carbon fibers to make up the structure and runs it thru a die and also injects an epoxy into the die. The die is heated to make the Epoxy setup. also he has to pull on the completed structure or it would get jammed in the die, thus making his day longer and your parts more expensive.

In the Pulltruding process ALL of the Carbon fibers run the length of the structure so it has the lowest strength to weight ratio...

msyed wrote:

Wrapped


The manufactures selects an internal diamater of a tube to make and he gets some steel rods in that diatmater that are polished quite fine. they coat it with some kind of release agent (usualy a specialized wax in a spay can) and place the rod in a computer controled lathe. They run Carbon tow thru a bath of epoxy and then turn the rod and wrap layers of of Carbon onto it in spefic angles to get the strength they designed it for. They then place the rod in an oven over night to make the epoxy set, then they pull the steel rod out of the completed tube that they then trim to length.

The usualy add more layers for more strength or use a larger diamater ID to make it stronger and lighter. They can also add extra wraps to the tube in spefic areas if desired.

This process is of course the most expensive to complete... but gives the higest strength to weight ratio..

msyed wrote:

Solid (well duh i guess, solid is solid Carbon)


Usualy Pultrruded but it does not have a hole in the center. These rods are usualy made in smaller diamtaters and are teh most flexable of the bunch.

msyed wrote:
2nd. Avia and SkyShark two makers of rods that are well known--strengths and weaknesses or there arent any ?


Their spars are designed diffrently so you have to select the proper product to fit into your application....

msyed wrote:
3rd. How do you know what diameter rods to order, what weight, and im guessing you can order rods only in set sizes? i.e. 32.5" size of rod.


That is sometime seat of the pants or just what do I have laying around... or how deep my pockets are at the time.

msyed wrote:
4th Ive looked through sooooooo many different rods, now my heads spinning with names and descriptions, and many sound the same!
Are there certain types of rods that people use in general for your regular freestyle dual line (made to fly in moderate winds? 3-4 mph +)?


it depends on many factors that are mutulay exclusive...

Cost
Durabiltly
Strength
Weight

msyed wrote:

Thanks


No Problem....
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AKA Harold
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P.S. Yet another post by the Squid..... Shocked Doesent he ever shut up???

P.P.S. The wind is like the air, only pushier.


Last edited by KiteSquid on Wed Sep 01, 2004 12:30 pm; edited 1 time in total
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Fred



Joined: 10 Aug 2004
Posts: 72
Location: Derry, NH

PostPosted: Wed Sep 01, 2004 11:42 am    Post subject: Rather than start a new topic... Reply with quote

...this topic seems close enough.

Hi folks,

If I wanted to beef-up the framework of an existing wooden framed kite that utilized 1/4" wooden dowels, would a fiberglass A20 be a good upgrade, or should I be looking at Carbon fiber?

I've blown out a few 1/4" spans of the wood . . . figuring I need somthing more robust, but I don't want to add weight if I can avoid it. I tried 5/16" doweling, and the kite developed some odd behaviors that I *think* is related to a weight-forward increase.

The kite in question is an 8' Double French-Military that I scaled up from my old "White Bird's" designed kite, and the spans in question are the upper spreaders. They fail in strong breezes on this kite, but work fine on the smaller White-Bird version.

It was one of my first attempts at scaling, and works fine in light wind, but I've grown fond of being dragged around the field and now fly it in stronger breezes regularly...untill it explodes that is. I thought about carrying a quiver of 1/4" shafts that I can swap in but I'd much rather ruggedize the thing.
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Progcraft
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PostPosted: Wed Sep 01, 2004 12:03 pm    Post subject: Reply with quote

Maybe somthing here can help you:
http://www.kitebuilder.com/forums/viewtopic.php?t=391

1/4"(6mm) wood=5mm fiberglass;

P.
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Fred



Joined: 10 Aug 2004
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Location: Derry, NH

PostPosted: Wed Sep 01, 2004 12:41 pm    Post subject: Helps a bit, yes. Reply with quote

I use Dan Leigh's data for my deltas, and it seems to work well. But what isn't conveyed is the relative 'durability' of the material, but rather the relative stiffness.

This would work if the following could be said:

For Stiffness: 6mm wood = 5mm fiberglass
For Durability: 5mm fiberglass = 6mm wood

Intuitively, I'd expect this to be the case given some of my unrelated experience with fiberglass constructions (non-kiting), but I have no experience specifically with spars, so ordering some blind would be a calculated risk.

Is it safe to assume that 5mm fiberglass will withstand more than 6mm wood?
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KiteSquid
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PostPosted: Wed Sep 01, 2004 1:12 pm    Post subject: Re: Helps a bit, yes. Reply with quote

Fred wrote:


Is it safe to assume that 5mm fiberglass will withstand more than 6mm wood?



I would say YES!!!

But there is a weight penalty.
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AKA Harold
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P.S. Yet another post by the Squid..... Shocked Doesent he ever shut up???

P.P.S. The wind is like the air, only pushier.
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