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Author: Subject: Wobbly Arc
flexiblade
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[*] posted on 25-6-2010 at 06:26 AM
Wobbly Arc


A little while back I had just set up my 12m Phantom on a new bar (airush 55cm) and shorter lines (20m - 65') and had it out in some decent winds (14 - 18mph). The problem I had was that I kept getting this weird wobbling effect right when the power started getting good. The spar edges would start moving rhythmically from front to back causing the kite to swing or wobble, seriously decreased pull and looked stupid as well. I switched back to my old bar and lines and everything was fine - would just like to use the bar without this happening again. Thanks



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[*] posted on 25-6-2010 at 07:12 AM


Sounds like its coming from shorter lines.

I'm certainly no expert but shorter line length might prevent the kite from spanning out like it needs to be.



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[*] posted on 25-6-2010 at 12:37 PM


The length of the lines shouldn't be an issue, especially at 20m. I have flown Phantoms on as short as 15 meter and haven't noticed what you are saying. What may be an issue is the quality of the lines. Not sure what type of lines you are using but cheap Dyneema or other brand lines will have a bit of stretch in them and can act like a bungee cord on your kite. As one pulls out and rebounds back, it loads up the others which will cause a "jellyfishing" effect on your kite. You may not even realize that your lines are stretching in and out as the bar will stay somewhat stable, but your lines are changing length on you without your knowledge.

To isolate the problem, I would start by using the same lines on both of your bars to see if it is the lines or the bars that is doing it and then go from there.


Hope this helps.



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[*] posted on 25-6-2010 at 05:51 PM


The bungeeing sounds like the culprit - they are a set of cheap pansh lines - the strange thing is that my older set are panshes as well but they never had the issue of bouncing the kite around as the new ones do - the old lines are are also 25m and not 20m - they should be exactly the same though. Can I stretch the lines to counter this effect? Thanks again for the input.



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[*] posted on 25-6-2010 at 06:09 PM


The Pansh lines that came with the ones that I had seemed kinda springy. It's likely the lines.



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[*] posted on 25-6-2010 at 06:23 PM


i have had the to and fro wobbling. only once on land several times on the water.

not sure what that is . not a line isssue

more of a pressure gradient pulsing within the kite and rebounding in flight. no real way of stopping it . power up it just does it faster. slow too fast and collapse or inversion can show up . i would just cruise til it settled about a minute maybe less.

it seems to pivot right at the front wing tip.

could be the LE gets kinked or deformed from sudden gust or reload of the internal webbing .

my first thought was the intakes leaking or the pressurization was just marginal on a clapped out old rig . don't really know .



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[*] posted on 25-6-2010 at 08:12 PM


I guess I'll just have to take her out again and give it a good shakedown - whenever that may be. Thanks again for the input guys, just shows that no matter how many sessions you have with a kite (this was about my 7th session with the phantom) it can still surprise you from time to time.



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[*] posted on 25-6-2010 at 08:25 PM


just wait, sudden collapse is just around the corna ,



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[*] posted on 26-6-2010 at 12:45 AM


Wish I would have got a vid of the v13 the other day, I thought it had been watching that old Flashdance video. It was everywhere and so was I.

Just crazy wind.

You guys figure it out, come back and post it, Please.



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[*] posted on 7-9-2010 at 09:23 AM


Was out at Sunset beach yesterday running the phantom and this old problem snuck back up on me. Whenever I would get it up to full power it would begin gyrating and wobbling, as mentioned earlier it used the spars as a pivot point for it's movement. Will try and adjust the internal strap to see if that makes a difference - then try some different lines (my only non-Pansh lines are 15m).



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[*] posted on 7-9-2010 at 10:48 AM


yesterday i was flying mine on a 55cm best bar, and noticed a little unpredictability in the kite... i think it is a little twitchy in the higher winds... its just responding to the changing conditions is all... i had the internal strap all the way loose... the problem got better when i let out the trip strap a little



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