direnc wrote:
I did the long mixet test along whole span of the kite on one side
Interesting. I am impressed. At the end of the day measuring the whole kite to fix it has proven to me unnecessary. More numbers are always interesting though.
One thing though
what force did you use to measure the bridles? Flysurfer uses I believe 5kg and anything over 1-2kg will restretch some bridles... Two problems with measuring, restretch effect makes measuring a shrunk line almost impossible to measure in it's shrunk state and unless you carefully measure with exact forces you won't get precise measurements... or at least not numbers you can compare with flysurfer...
direnc wrote:the shrinkage seems almost uniform along the span
It does on your final DIFF numbers, though there is some variance. Your use of negatives and positives in your numbers are a bit confusing, I will just assume they all indicate shrink though they look as stretch.
direnc wrote:That's why I expected the mod to work.
Measurements may be wrong, current kite shape may not work with standard settings, differences measured may be enough to cause the problems. Overall many reasons measuring things can be a waste of time.
direnc wrote:
You mention the B limit often, could you please explain what it is exactly?
When the mixer fully extends to depower, B hits a limit. This limit affects the depower of the kite. The mixer and kite bridles will shrink to reduce the B limit. This has a large effect on the kites performance. Kite will fly slower, depower less and stall easier.
People often reduce B to increase stability. This has two effects, making the profile more stable and reducing depower, also more stable. It is not necessary to alter B to get the more stable profile, Z and to a lesser extent C can do that. It is also not necessary to alter B to reduce depowering, you can do that with trim... Therefore it is not necessary to alter B to increase stability. It is however necessary to alter B by extending it to improve depower, but also extend C and Z so the profile is the same, as most should want.
direnc wrote:
Those measurements from HaylingBilly are not the at the mixer, but at the kite end.
Thanks, confusing. If they are differences then may be more ok I guess. If they are measure changes then same as mixer or kite end, and crazy.
direnc wrote:
Second hand kites that are out of tune and the desire to make them fly as they should...
Ok. Restore B limit at least at mixer, should be +25cm for most Flysurfer mixers. You will need mixer level at the +25cm, I did a thread on it and made it very complicated,lol. Need a link?
You could compensate on top of the B limit for B shrink at kite, I usually estimate 2cm, from my many measurings. As you have measured 5cm you could add that, though that is a lot, and I am doubting your measurements used 5kg. Maybe just use 2cm as my measurements are quite good. So make B limit 27cm.
You could redo your long mixer test if you want with 5kg at the center, but I never use a long mixer test so I don't think it's necessary. Lets forget that unless you insist
Adjust Z till you are happy with the kite
. You will have needed to make an extension or at least rearrange things for Z to fix the B limit. Use that to play with it's length till you are happy with how the kite flies. As has been stated a million times now longer Z= more stable, less power, lighter bar, better upwind, shorter Z is the opposite. Use the behaviour of those attributes to guide you in which different way you want to change Z. Unlike B and C, Z is much less sensitive to change and you will find adjusting it easier. You can even do a setup with knots and larks heads to quickly change even for different conditions.
If you want to get more involved, restretch your bridles. Particularly Z as most change occurs there. Need a link on that?
direnc wrote:Again, thank you for your help and patience.
Thank me when it's fixed
I have spent a lot of time and effort to understand foil kites better. I like to help and can short cut your understanding to where I am now if you have the patience to read and understand what I write though it can be difficult for some I know. Do ask questions, no reason to pretend to be smart by remaining dumb.
I had to weed through many falsehoods about foils when I started with them. Very specific ones like line shrink/stretch, b limit stuff and then general things with relaunch and performance etc. stuff PMU posts lol.