The Kitebuilder.com Forum

Kitesquid · Posted: Mon Jan 05, 2004 9:44 am Post subject: Graphite_Discussion

The SkyShark P100, 200, 300 and the new P90 are special tubes, as you can cut and furrell them anywere along the length. Some Carbon tubes have build-ups at the ends and you cannnot cut and furrell them in the middle and expect any longetivy.

I use the P100 and P300 a LOT in my kite building. I used ove sixty P300's on my Thomas Jefferson kite.....

Pete Dolphin used about 100 of them in his member's choice kite at Dayton.

this spar is hard to beat, except in the price catagory....
_________________
VR/
KiteSquid
AKA TakoIka
AKA Harold
King George VA

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

wdrwilson · Posted: Mon Jan 05, 2004 11:13 am Post subject:

Squid,

Kitesquid · Posted: Mon Jan 05, 2004 11:51 am Post subject:

This ONLY applies to wrapped tubes. It does NOT apply to pultruded tubes. I guess I should have said so in my previous post. So if you are using pultruded tubes you can disregard my comments....

also if you are not spiltting tubes at the furrell, or at any other spar to spar connection, you can disreguard this too.

Look at some wrapped Carbon tubes, and you will see about the last 3 inches of it are fatter than the rest of the tube. That is were the "build up" is. They reinforce the end of the tube because that is where the furrell goes, and that is were there will be a concentration of forces.

Sport kite buiders use more wrapped Carbon tubes than pultruded tubes as they are stiffer for the same weight, or said another way, they are just as stiff and weigh less.... Weight is a big issue in ALL kite building as you have to be able to lift the weight of the "Kite System" to make it fly, to put a smile on your face!!!!!!

To get the weight out of the wrapped spars they make the wall of the tube thinner, but it still has to be strong at the ends were all that energy has to be transfered to the furrell, therefore the buildup. It adds hoop streingth.

Fishing rods usually have a thread wrap at the end to reinforce them. It can be a beuatifull art and Glenn Haynes and myelf have used them on some of our single line kites to strengthne them and to add decoration to the spars. Look at some custom rod builders creations to see the apex of the art.

When you make a choice of the spars to be used in a kite you have to make your decision biased by the following:

Stiffness

Weight

Durability

Cost

Some factors are a higher priority than others. For me Cost is usualy the last think I look at, as I can wait to save up some $$$$ to make a GREAT kite insted of making a good kite today. A light yet strong kite will see more air time because it will have a wider wind window. Where I live I normaly see 3 mph winds. I travel to so my kites have to be able to fly at the beach in a 25 MPH wind too....
I have stopped buying Fiberglass tubes and now only use Carbon in all my kites including my last creation, a Sharonie kite that was about 12 feet tall by 8 feet wide and took about 60 SkyShark P300 tubes to build!!!!!!!!

So Light And Strong = Carbon Tubes = less $ in my pocket = less kites in my bag but = More smiles for me!!!!!!!

Look at all the kites you can to see what materials and construction techinques are used. Sport kite competitions are some of the best ones. I even learned to use a Double Sheet Bend to tye brides.....

Does it make sense now???
_________________
VR/
KiteSquid
AKA TakoIka
AKA Harold
King George VA

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

wdrwilson · Posted: Mon Jan 05, 2004 12:07 pm Post subject:

Thanks for the clarification, that is a lot of very helpful information...

--Bill

Kitesquid · Posted: Mon Jan 05, 2004 1:03 pm Post subject:

No problem...........

I assume you were using pultruded tubes. Am I corrcet?
_________________
VR/
KiteSquid
AKA TakoIka
AKA Harold
King George VA

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

wdrwilson · Posted: Mon Jan 05, 2004 1:46 pm Post subject:

Yep you are correct....

--Bill

Stan · Joined: 18 Nov 2003 Posts: 150 Location: So Cal

Skyshark P2-7 spars are reinforced at the ends for the joints. Cutting them produces a weak spot, especially when using internal Ferrels.

I had a hard time with pultruded Carbon for my small Rev-type Shortwaves. Any gust or bad landing snapped the LE, and I kept using larger spars until it flew like a brick. I replaced the spars with J65 fiberglass and dropped a bit of weight while preventing any more breaks.
Lately I use A/C or Skyshark, but J65 is still doing well in my original kite.

After using various online charts for spar selection, I've found stiffness-to-weight ratios leave durability out of the equation. Fiberglass is amazingly rugged and cheap for us tightwads on a budget. I'm intending to use FG for a large Bean traction kite.

Stan

Kitesquid · Posted: Mon Jan 05, 2004 2:39 pm Post subject:

Yep Fiberglass is very durrable.

But I have yet to break a Revolution Super Leading Edge tube while flying a rev kite, but I am discounting the time I played "Dancing Bear" on one of them that was on the ground, and supprisingly it was one of my kites I broke that day.

Large Diamater, Thin Wall, Wrapped Carbon fiber (or to be a little more technical accurate Helicaly Wound Carbon Ribbon) in an Epoxy Matrix is THE spar to beat, except in price...

But I cannot find a fiberglass tube that is any near as stiff as a SLE tube.

BTW what does A/C mean? I assume it means Avia Sport Composites.

in the wrapped Carbon line:

Yes the SkyShark 2P, 3P, 5P and 7P are reinforced at the ends, but they are no longer in production, and have not ben made for several years.

SkyShark only makes the P90 (also called a PLite), P100, P200, P300 in their non-tapered line and the 2PT, 3PT, 5PT and I think they make a 7PT in their tapered line... but I have been known to be wrong from time to time.

Avia makes a tube that is comparable to SkyShark's tapered line and a tube that compares to the construction of the now out of production 2P-7P line called the XL. I use em too.....

In the Pultruded line of kite spars:

Avia makes pultruded Carbon tubes in a wide range of diamaters and rods of several small diamaters also. They also make some unidirectional Carbon ribbons and I have a use for some of them now too....
_________________
VR/
KiteSquid
AKA TakoIka
AKA Harold
King George VA

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

Stan · Joined: 18 Nov 2003 Posts: 150 Location: So Cal

Was comparing FG to standard Carbon for durability. Many builders (myself included) still use pultuded spars to keep costs down.

I can buy "obsolete" Beman UL, SS ?P or Easton aluminum/Carbon (A/C) spars locally, so they haven't all disappeared yet. Very Happy

Cheapo Stan

Kitesquid · Posted: Mon Jan 05, 2004 3:23 pm Post subject:

Great!!!!!!!!

Pultruded spars do have their uses!!!!!!!!!!!!!

Aluminum Carbon tubes are not found in my area......

I like to try all materials at least onec. I even skin some kites with trashbags!!!!!!!

I do wish my pockets were a lot deeper than they are. I would love to experment with boron and wraping Carbon here at home to build truly custom spars and fittings!!!!!!
_________________
VR/
KiteSquid
AKA TakoIka
AKA Harold
King George VA

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

Stan · Joined: 18 Nov 2003 Posts: 150 Location: So Cal

A few techies here have used boron/Carbon but the results weren't earthshaking I guess. They were using some spinoff from bicycle frame methods to line the tubes with axial boron ribs.
The flat Carbon stock is catching on here for fighters with 5 or 9 point bridles that regulate the spine curve. It is more consistant than bamboo.

Stan

stevef · Posted: Tue Jan 06, 2004 9:01 am Post subject:

Stan · Joined: 18 Nov 2003 Posts: 150 Location: So Cal

That's a perfect fighter spine size. I'd bet your sales of that and 050 - 060 rod are to fighter junkies. A fellow here bought a mini drill press just to drill holes in that flat Carbon stock for multipoint bridles.
Lots of fighter makers here in San Diego! When the wind dies in late summer, we all get together until sunset at the beach and swap ideas and kites.

For some reason the forum has trouble with the spelling of ferrule. Very Happy

Stan

Kitesquid · Posted: Tue Jan 06, 2004 11:36 am Post subject:

Stan,

What do they use to drill the Carbon ribbon? Carbon can dull a blade in a hurry!!!!!
_________________
VR/
KiteSquid
AKA TakoIka
AKA Harold
King George VA

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

Stan · Joined: 18 Nov 2003 Posts: 150 Location: So Cal

A common twist drill goes right through.
When making fighters. sometimes I'll cut a dozen bows with one Xacto blade.

Stan