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Spar weights.... an investigation 
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Joined: Mon Sep 29, 2003 7:43 pm
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Location: Vihtavuori, Finland
Post Spar weights.... an investigation
During my last trip to work I had the pleasure of sitting next to a charming woman who, in addition to her work as a marine biologist, was something of a keen archer.

One thing that our conversation happened across was carbon spars (charmer that I am). She informed me how the latest arrow shafts' main advantage is that they can be had in very closely matched sets so that each arrow in a quiver is the same. Consistency, see ?

I wondered about our little part of the world was being treated in terms of carbon. I used to regard this as a pretty good guide to things but armed with an accurate to 0.01g balance I set off to check on the (few) spars I had in my spares collection.

Here's what I found:-
Code:
3PT II      13,28g +/- 1%
5PT II      16,53g +/- 9%
Nitro       15,01g +/- 3%
P400 Camo.  19,27g +/- 3%
P100        12,96g +/- 3%
G-Force UL  13,61g +/- 3%
G-Force SUL 14,77g +/- 5%


In other words... our stuff is crap. :angry: A set of Easton X10sare guaranteed to be within 0.5 grains of each other. That's 32 milligrammes or 0.03 grammes. Even the cheap end of the scale are +/- 0.3 grammes and only the 3PTs came in under that.

As I don't have any spare AeroStuff (and I'm not taking my kite apart either) I can't say how much better/less crap these are. If anyone wants to send me some for research purposes..... :wink:

I'm frankly shocked :shock: . I went back and re-checked everything to be sure, to be sure. It is often said that the original carbon used for kites were rejected arrow shafts but, dear goddess, this is beyond a joke.

It's obvious that the manufacturing method exists to create in quite large numbers accurately matched carbon tubes. It's just that we ain't getting them.

I might pull a few more spars out to check these too.

Mike.


Sat Jul 29, 2006 2:52 pm
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Would it make that much difference Mike, an Arrow goes from A-B, normally in a staight line (hence the quality issue)..a kite goes from X-P and sometimes to G...

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Sat Jul 29, 2006 3:05 pm
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I think that it would. I suspect that one of the results of the difference in weights is a difference in stiffness. We've also all seen the non-concentric holes in the spars, had spars break at freakish moments and others that seem indestructible.

The mass differences are just one of the ways we can measure the crapitude of these things.

Mike.


Sat Jul 29, 2006 3:08 pm
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Isn't there a pay for what you get issue here.

I'm sure if wanted close tolerance spars you could specify that....
Of course no doubt that would probably at a premium on the price.

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Sat Jul 29, 2006 4:13 pm
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kevspilly wrote:
Isn't there a pay for what you get issue here.

The over-the-top-of-the-range X10 retail for about £19 each.

Fatboys, which I'm reliably informed are as much as all but the very demanding will ever be able to make use of, go for less than £6 each.

Now I ask you.... who is being taken for a ride here ?

Mike.


Sat Jul 29, 2006 4:41 pm
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I've seen carbon tubes being made by pull extrusion and wrapping techniques and I also know that the process is a tricky. High degrees of monitoring/ intervention are required to get consitent results.

In more automated processes there would probably be a fairly high rejection rate for close tolerance control. If the rejects are then sold on for kite use and sold as "the best technology can produce" at premium prices that sucks!

Though I guess if big profits were to be made in kiting, rod manufacturers would orientate their production to this specialisation. Perhaps its a volume of sales argument, lots of arrows versus relatively few kites rods.

Incidentaly I "think" the industry standard 82.5cm rod length originates from standard arrow length.

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Sun Jul 30, 2006 7:54 am
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Miles F wrote:
Perhaps its a volume of sales argument, lots of arrows versus relatively few kites rods.

Arrow shafts are made in a variety of weights and diameters. Retooling and manufacturing to "kite sizes" doesn't seem like a major stretch but I'll probe a few contacts and see what they say.

I'll also ask from some folk I know envolved in ski pole manufacture - these guys can make ovoid-to-round profile, multi-thickness tubes of over a metre in length for prices that put kite spars to shame too. :evil:

Quote:
Incidentaly I "think" the industry standard 82.5cm rod length originates from standard arrow length.

And you'd be right. :bigups: So the original stunt kites were that size because of the archery industry.

Mike.


Sun Jul 30, 2006 8:47 am
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eastonarchery wrote:
The grueling mental and physical pressures are enough to break the most seasoned veteran. CONFIDENCE in your equipment is vital to survival in sudden death, head-to-head elimination matches.


WTF? Do they shoot those X10's at each other then :shock: ????

Think I'll stick with my slightly asymmetric kite...


Sun Jul 30, 2006 1:57 pm
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Oval spars, now there's a thought.

I recently had avia .230 which had some blemishes in it, just a couple of dents and a small area where the top coating was missing. I was desperate so rather than making an issue and snding it back, I used it. Snapped right on the blem, so I have to agree that it would be worth paying a bit extra for higher quality control as I'm sure we'd get less breakages. Not sure about the weigth thing though, once a kite has a few tufts of grass and dog poop on it, a fraction of a gram here & there can't make too much difference can it?



...Or is that just me :oops:

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Sun Jul 30, 2006 7:59 pm
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Easton Vector shafts are £4.65 each at Quicks (who used to have a walk-in shop not 10 miles from where I live).

I can't see any specs for them on the Easton site, but if they're as good as even the fatboys it might be worth me checking them out.

I wonder about taking a couple of Skyshark sticks into Quicks, I'm sure, as enthusiasts, they'd be interested and happy to help.

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Mon Jul 31, 2006 12:17 pm
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My 5pt II's weigh 15g and a couple of AeroStuff Gold S's weigh 13g. I haven't gotten into that whole "tenth of a gram" thing, yet. :shock:

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Mon Jul 31, 2006 12:49 pm
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randyg wrote:
I haven't gotten into that whole "tenth of a gram" thing, yet. :shock:

A tenth of a gramme !! A TENTH of a gramme ?!?!?1

We have no place for such wild inaccuracy. One-hundredth or you might as well be guessing. :evil:

And none of my 5PTs weighed close (in my terms) to 15g.

What about dem Icones den ? :-)

Mike.


Mon Jul 31, 2006 1:03 pm
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