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#1 Jeepster

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Posted 24 June 2008 - 07:16 AM

Yes, I know that engineers are nerds ... they love numbers and looking in places that other (more normal?) folks never think about looking. So, please don't roll your eyes and sigh. The kite shop called Rev and told me they had a good laugh at my suggestion that the silver label rods are lighter than the gold label rods. That's probably true ... not the laughing - I'm sure that's true ... but, the idea that the Silver label rods are uniformly lighter than the older rods.

However, I've noticed that the stated weight of the different rods sets varies in different posts. In fact, Ben once stated a rod weight and then the next day, in the same thread, stated a different weight for that same rod ... not a complaint, just an observation. So, I got out my reloading scale ... double checked it's accuracy with a benchmark weight set ... and weighted my rods. My rods are from a new, non-vented B-series kite and have the silver labels.

The four 2-wrap rods weighted an average of 10.9 grams with a standard deviation of slightly more than 0.2 grams.
The four 3-wrap rods weighted an average of 14.7 grams with a standard deviation of slightly less than 0.2 grams

Those figures are well off the generally stated weight of 14 grams for the 2-wrap and 19~21 grams for the 3-wrap.

What does this have to do with flying your kite ... probably nothing. I'm just curious about how much the rod weights really do vary. Manufacturing processes that produce rods, like we use, with the correct balance between cost and functionallity will necessarily have some deviation. Since there's no wind right now, I've got time to be curious ... does anybody have any experience, data, facts, etc on rod weight variation?

#2 beach

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Posted 24 June 2008 - 08:49 AM

Well here we go, rod weight is different because of the resin content in the raw materials and barometric pressure
during the cooking process, hence the changes, but in retrospect the weight difference is not enough to matter
that much and really not noticeable. These changes will happen unless you spend time measuring the resin content
of each piece of raw carbon on the roll. You have to do this when say making medical parts but for rods
what really counts are reflex and strength so rather than spend more time and money on making say perfect weight
rods we concentrate on what really matters and live with the slight differences in weight. The thing is time equals
money and I'm trying to keep the cost down and the product top shelf for us the fliers so for these slight differences
in weight I do have to make sacrifices. Heres one for you the cost of petroleum products have risen 37% to date this year
yet my rod price have not, so try selling that to a board of directors. I do understand the concern but I also know that
even with these slight differences in weight we are putting out a great rod and if you can tell the difference in the weight
just by holding the rod your a better man than me.......So with all that being said lets see if this helps...Ben :blue-cool:

#3 Jeepster

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Posted 24 June 2008 - 09:38 AM

Well here we go ... rather than spend more time and money on making say perfect weight
rods we concentrate on what really matters and live with the slight differences in weight. The thing is time equals
money and I'm trying to keep the cost down and the product top shelf for us the fliers so for these slight differences
in weight I do have to make sacrifices. ... I also know that even with these slight differences in weight we are putting
out a great rod and if you can tell the difference in the weight just by holding the rod your a better man than me.......
So with all that being said lets see if this helps...Ben :blue-cool:


Ben,

Thanks for the quick answer.

There was never any question in my mind that you are producing a great product with the correct balance of cost and quality ... both are important to me. And, as a newbie, I probably can't tell the difference between a race rod set and a SLE set ... yet!

It does look like everything aligned for both of my rod sets. They came out much lighter than I had expected ... and I need all of the help I can get at this stage of the learning experience ... anything to make the kite stay up on a light wind day. As to strength ... if they were weak, my first few days of flying would have uncovered that fact. I carried a shovel in the Jeep to dig the kite out of the ground for the first few days. Seems that the forum discussions center more on which knot to use ... I finally ignored the knot suggestions and worked with balancing the handles around my middle finger when the kite was hovering in the center of the wind window. After that breakthrough, I could leave the shovel home.

My question was merely one of curiosity. Most forum posts quote the rod weights as if they are a "fixed" number, when as you discussed, the rods will fall into a range of weights.

Cheers,
Tom

#4 big bri

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Posted 24 June 2008 - 11:22 AM

WELL,Wher the heck are Sailor,Jonsey and Choccy when you need them.


Go fly fellas :P .. :lol:

The silver labels i have made an error with.I mixed my 2wrap up with Race Rods.Flew with Dave B and was bullish how the Race Spars had the edge on the 2 wrap.
I had 2wrap in and didnt realise at first.Due to just checking the couloring of the label.Rather than the labeling properly.Ther now both silver offcourse.

BRIAN... :)

#5 Jeepster

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Posted 24 June 2008 - 11:40 AM

The silver labels i have made an error with.I mixed my 2wrap up with Race Rods.Flew with Dave B and was bullish how the Race Spars had the edge on the 2 wrap.
I had 2wrap in and didnt realise at first.Due to just checking the couloring of the label.Rather than the labeling properly.Ther now both silver offcourse.

BRIAN... :)


Brian,

Actually, I suspect that Ben is pulling our leg with all that technical talk. I think the silver labels are the real secret ... the gold labels were the heavy component. There'll probably be a black market in light weight silver labels in the coming months.

Thanks for making my day with your comment about bragging up your new "race rods" ... just adds support to the theory of the lightness of the silver labels.

Cheers,
Tom

#6 Sailor99

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Posted 24 June 2008 - 12:21 PM

WELL,Wher the heck are Sailor,Jonsey and Choccy when you need them.

Flying my friend.

There are only really 3 components to the rods. Carbon, resin and labels (+ of course air in the hole but lets ignore that). Quite clearly the labels are the most important of these in terms of both weight, inertia and modulus (go on, you'll have to google modulus and inertia, but to give you a start area is measured in m2, volume in m3 and inertia in m4). Essentially if you have a silver rather than a gold label then it reflects more photons and thus you will find that the rod weighs less although it is of course the same mass. Also if you measure the weight at a point nearer the tropic than another place, close to the equinox, you are nearer the sun and therefore subject to a greater gravitational force. As such the rod weighs less although again its mass is unchanged.

So I don't think it has anything to do with the carbon content which is negligibly light. Nor to do with the resin content, although resin is much heavier. Nor do the autoclaves have any significant impact. As for the pressure, humm. Yes it affects prepregs but not by over 30%. It is clearly just the colour of the label and where on the planet it is weighed.

As to the weight differences being negligible, if the measurements are correct they put a 3W at pretty much the same weight as the stated weight for a 2W. Which means of course that you may as well throw away your 2Ws and use stronger 3Ws with a 2W designed weight.

Will that do you Brian?


Over - Jeremy

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Knowledge: The small part of ignorance that we arrange and classify.

#7 Kitelife

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Posted 24 June 2008 - 12:42 PM

Pfft, minor weight differences are inconsequential... Tuning and technique is 90% of it.

I can appreciate just "wanting to know" as a tech-head, but I've never weighed my spars, and never noticed any oddities in flight due to weighting.

But, I can feel if one of the lines is 1/2" longer than the others, in flight.

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#8 big bri

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Posted 24 June 2008 - 01:38 PM

Im with the Champ on the tech stuff.Time on the lines is wher the diffrence is.

Jeepster,weve all been custards at some point,dont fall for the micro,meganutens downforce,theory type things.Fly it,feel it,Love it.Always remember.Bens never wrong.He cant be.Hes super kewl.

Sailor,your mad my freind,but kewl.Im in tears at times laughing.Google,the practical alternative to ,,,,well,everything.


Keep flying gents.ENJOY


BRIAN...A custard 1st class

#9 Jeepster

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Posted 24 June 2008 - 01:40 PM

Tuning and technique is 90% of it ... I can feel if one of the lines is 1/2" longer than the others, in flight.


In 1982 a select group of bicycle riders started a race across America (RAAM) from the west coast to the east coast ... the winner completed the race in under ten days. I had an opportunity to listen to Lon Haldeman, the first winner, give a presentation. Several members of the audiance kept asking him questions about the equipment he was using. Finally he answered that as long as you were not using a bike built from water pipe, it was really the rider and not the equipment.

Your answer sounds like an echo of his answer. I'll take it to heart.

Now, as to that 1/2 inch longer line, I'm pretty sure that if you check on that side of the kite, you'll find gold labels on those rods.

Cheers,
Tom

#10 Jeepster

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Posted 24 June 2008 - 01:44 PM

Tuning ...


I haven't found the knobs yet to tune it ... where are they?

Actually, if it didn't come from the factory correctly set up ... I'm not smart enough (yet) to fix it!

Cheers,
Tom

#11 Kitelife

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Posted 24 June 2008 - 01:48 PM

Jeep, sorry, you may have mentioned it before... But do you have an SLE or a B-Series?

GREAT discussions on tuning here:

http://www.revkites....?showtopic=1205
http://www.revkites....?showtopic=1315

John Barresi

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#12 Jonesey

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Posted 24 June 2008 - 01:49 PM

Did I ever mention I used to work for a company that made carbon yacht masts .... we never used gold labels ... too heavy ....

Sailor .. if your throwing away your 2 wraps I'll have them. :lol: ...

shouldn't we be comparing moments of inertia, bend characteristics and durability rather then just the weight ?

I think that the small amount of hours in a week we can fly means that all this technical discussion is our only outlet for all the pent up frustration from not flying...

great fun and occasionally educational ... but I am relieved to see that like every other sport I've ever been involved in there is a healthy level of BS mixed in with some dubious technical knowledge all of which has no bearing at all to the real agenda ... flying the bloody things better!

Personally I love trying to figure out how things work, how they can be improved, why they broke etc but I think I have come to the conclusion with Revs that when I can fly one at 100% or more I will worry about tweaks and changes in the meantime its 'buy em and fly em' for me....... doesn't mean I wont place both feet firmly in my mouth and wade in on here though ;)

#13 Kitelife

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Posted 24 June 2008 - 01:50 PM

Now bend characteristics, there's a viable factor.

John Barresi

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#14 Jonesey

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Posted 24 June 2008 - 01:53 PM

Now bend characteristics, there's a viable factor.



Just spent the evening playing Wii Fit with the kids so I can tell you officially I have the bend characteristics of an old woman :lol:

#15 Jeepster

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Posted 24 June 2008 - 01:57 PM

Jeep, sorry, you may have mentioned it before... But do you have an SLE or a B-Series?


I have a non-vented B-series. Would of had an additional vented B-series, but Choccy pushed to the head of the line. And, now she won't share.

Thanks for the threads ... and for the fun today ... yep, the wind in this area has been too low to fly ... well, the wind outside, that is.

Got to go take the wife to dinner or I'll never get my second kite.

Cheers,
Tom

#16 big bri

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Posted 24 June 2008 - 01:59 PM

Your smart enough to be a member here my freind.Someone will know how to fix it.Even if you dont.

Keep asking.


I once read about some old Aussie farmer that entered a marathon or Ironman race over[or down under depending]in Ozz.Cant remember the tale properly,but it went something like.

He enters race as he neads the cash desperatly.Never realy looked at the rules,previous records or best ever times,so no precons.Just was a half handy runner.No special trainer,clothing.NOWT...
He wins by days infront of everyonelse.
Turnsout,he didnt know he could STOP AND RESTKnobody told him he could.

Obviously an ENGLISHMAN :lol: :lol: :lol:

BRIAN...Waits for green and gold back lash

#17 big bri

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Posted 24 June 2008 - 02:07 PM

I have a non-vented B-series. Would of had an additional vented B-series, but Choccy pushed to the head of the line. And, now she won't share.

Thanks for the threads ... and for the fun today ... yep, the wind in this area has been too low to fly ... well, the wind outside, that is.

Got to go take the wife to dinner or I'll never get my second kite.

Cheers,
Tom


Ha ha.The wives.

Heres to wives and Lovers.May they never meet
Quote by Captain lucky jack[aka Russell Crow]

BRIAN...

#18 Aerochic

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Posted 24 June 2008 - 04:15 PM

I haven't found the knobs yet to tune it ... where are they?

Actually, if it didn't come from the factory correctly set up ... I'm not smart enough (yet) to fix it!



Check those line lengths pronto, Tom. It might save you a world o' touble. :)

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#19 antman

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Posted 24 June 2008 - 05:17 PM

Now bend characteristics, there's a viable factor.

i agree while their is a slight difference in rod weight with all the rods the flex plays a big role i think .. the 4 wraps are stiff witch means less flex for the heavy winds while the race rods have the springy flex needed for the light winds.. i do have a black dimond and rev indoor frame cut down to a 1.5 size and i find that one to still be the best because of the m,ost flex they have to absorb as much wind as possable.. it is true that the indoor rods at the thinnest and lightest rods ive seen from rev.. but correct me if im wrong i still think the flex for the sail determines the peformance in the end.
GOD PUT ME HERE. TO ENJOY THE WINDS

#20 Jeepster

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Posted 24 June 2008 - 05:20 PM

Someone will know how to fix it. Even if you dont. Keep asking.


Bri,

My mother's maiden name was McNicol ... so, I grew up with stubbon as a household characteristic. Love the Scots, but it's very telling that Scotland has the thistle as their country's floral emblem. So yep, I'll keep asking.

Cheers,
Tom




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