foilholio wrote:It explains one of the problems but not all.Henk wrote:Your knowledge might explain why some kites don't fly well even though the mixer test is ok.
I think it may not calculate the B main exactly correctly, but it is not necessary as I just made it to demonstrate how things interact. B Is being limited because of the C pulley line, so the length of B pulley line is not really important. Just because C adjustment changes B won't change a thing. They still get lined up the same and that leaves B too short any way you look at it.Henk wrote: I have a few questions I hope you can answer:
- It seems that your Excel model of the bridle does not take into account the attachment point of the B-Pulley line to the C-main. It is mentioned in the comments, but wouldn't this have quite some impact as in effect the B-Pulley line will be longer than calculated?
Adjust when you run out of trimmer adjustment or don't like it always being depowered.Henk wrote: - I would like to understand what kind of maintenance I need to do on my new 15m Speed5. I came up with next schedule:
+ Bar line length adjust after 20h (for shrinkage)
When ever you feel like it or feel the kite doesn't seem right.Henk wrote: + Mixertest and bridle lines check after 60h
Pulley lines break with some warning, the outer sheath breaks which creates a noticeable bump when sheeting in/out. You don't have long to ride after that before the inner breaks though maybe 10-20mins depending how much and how you use the bar. You will probably miss the sign though, don't worry too much as the kites can still sort of be flown with a broken pulley line, I wouldn't want to be too far from shore though as mainly down wind riding is possible and the kite can collapse easy if you don't manage it well.Henk wrote: + Exchange pully lines after 100h
With experience you can tell when a pulley line or any line, depower etc, is too worn and needs replacing. Heavy fraying and broken strands is a strong indicator.
Sprengers last a bit longer than ronstans, in practice ronstans wear out before the pulley lines and then proceed to destroy them. If the pulley has a lot of play or doesn't roll nice it should be replaced, I generally replace pulleys and pulley lines at the same time. You can feel at the bar when pulleys are worn, they give a notchy bump bump bump feel sheeting in and out.Henk wrote: + Exchange pully after 250h
Henk wrote: * Is it also possible to re-stretch the bar lines and pulley lines, to prevent to need to make adjustments?
You can restretch any line but it would seem not to original length, so no. Pulley lines and front lines require perhaps more force than you can easily exert to restretch them. The rear lines can be restretched by throwing your whole body against them, and the fronts too but less so. You can break the rear lines so watch out. Good though rears are easy to restretch because they change/shrink the most. In generally though it is just easier to adjust the lengths as you end up in a continual cycle of restretch shrink and repeat.
A mixer test sets the mixer to level. A long mixer test sets the kites upper bridles to their original relationship at a level mixer, it does this by changing the mixer to some thing other than level. This is based on some measurement of the current upper bridle relationship and comparing it to what it should be calculated from the line plan. In reality the span of the kite is uneven so it is impossible to achieve. i.e. measuring and adjusting for one part is not correct for another. like center compared to tips.Henk wrote: * What is the difference between a long-mixer test and a normal?
Simply look at the pictures, it is a knot on the rear main which you move the end of the C pulley line to. You set the knot based on a measurement on A and B difference when fully depower , it should be 25cm. Then when you level the mixer it is all correct, you may run out of adjustment on C main, you can make an extension for it.Henk wrote: - Can you clarify what is needed for your mod and when? So if I understand it correctly, you need to adjust Z and C to keep the mixer even AND the A/B ratio. What should I make for this, an adjuster for back line length? Isn't it easier to swap the pulley lines more often or re-stretch them? Or is it also about the bridle shrinkage of the main lines? Would you recommend to take measure of all lines, now the kite is still new?
I have ideas to design a better mixer but have yet to go from paper.
If you don't mind can I post this in the thread so i don't need answer again the same questions?
Of course Z must not be slack when fully sheeted in, it must be tighter. How tight, is a bit personal question. If Z is too tight kite becomes twitchy in its behaviour, if too loose turning suffers and some performance is lost.foilholio wrote:if you can observe your bridles and Z is always slack even with the bar in, which seems common for flysurfers
foilholio wrote:Merely looking at the mixer producing AoA or a complete profile with ABCZ is wrong I think.
kitexpert wrote:Of course Z must not be slack when fully sheeted in, it must be tighter.
kitexpert wrote:How tight, is a bit personal question.
This I have not so noticed maybe you mean it is less stable?kitexpert wrote:If Z is too tight kite becomes twitchy in its behaviour
kitexpert wrote: if too loose turning suffers
Lift will be lost but L/D can improve. Didn't we discuss this before?kitexpert wrote:and some performance is lost.
kitexpert wrote:Observing the line rows and possible folds in upper and lower skins tell a lot when adjusting kite bridle/mixer.
kitexpert wrote:It is easiest to see when some one else is flying the kite.
what did you say?kitexpert wrote: Almost certainly original settings are the best.
but yes original is good. The designer would have spent much effort on it, unless maybe Panshkitexpert wrote:How tight, is a bit personal question.
True and true. But the mixer and profile can only align at one single point, or at most a very limited range, for all others their will be distortions.kitexpert wrote:Mixer tinkering means that some distorsions to panels will result and it has limited possibilities to correct bridle stretch/shrinkage.
Big incorrect there. They all interrelated i.e. tension one it loosens the other.kitexpert wrote:Adjusting brake tightness is actually not mixer related matter, it is always pulled straight 1:1, with or without speedsystem.
Nope both can affect it.kitexpert wrote:If kite has increasing camber at higher AoA's it is related more linerow locations than the mixer, especially so with most common 1:2:4 mixer.
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