The problem with flysurfer mixers.

[jakemoore]

I'm just giving you the respect of trying to understand what you are writing.

Just my opinion but I'm a big fan of a shorter bridle and therefore a shorter B sparepartline. If the B is really hitting the end where it meets the C sparepartline in flight maybe its time to replace the B sparepartline? My experience is the C-sparepartline wears through and then I change all 4 sparepartlines when the sheath breaks, so I have not experienced this.

Anyway the advice from flysurfer is to line up ABCZ, this will generally work fine, if you have a shrunken bridle problem it is better to restretch your bridles as things change cord and spanwise. It is possible though to account for most shrink by shortening B and C or lengthening Z. Something like a Z mod will be needed and can be used to achieve it.

I think you are on the money with regard to restretching or pig-tailing the little bridles for an older kite, but I'm not convinced the Z main makes a difference specifically in and of itself. That is to say if the mixer is in tune (A=B=C=Z) but the Z main is shrunk, you can just compensate by depowering at the bar to that point.

[foilholio]

I am repeating myself a bit but the B pulley line doesn't limit B, the C pulley line does. It's because B pulley line is longer and C pulley line is shorter.

If you look at the excel sheet you will see Z main shrinking or C pulley line shrinking causes the AB limit to reduce and so with it depower. It is pretty subtle especially day to day but if you have a 7-10cm shrunk c pulley line and you fix it, you will notice the difference.

Do you not notice a difference in the kites performance when you change pulley lines ? Why is that? ABCZ is still even!

Changing the length of Z is important to keep it in correct alignment with B and C when wanting to change their lengths too.

I usually only replace pulley lines after they break. I replace all of them and the pulleys.

[Mossy 757]

So go back to the part where this is about a problem with Flysurfer's mixer...

Mixer test and tuning your bar will solve 95% of performance issues but every once in a while you need to measure your bridles from the power ribs; if you believe Ozone's recommendation from the R1, that's at about 60 hours of flight time.

[foilholio]

The problem with flysurfer mixers is the test only accounts for half of the pulley line shrink and their is no way without a mod/s to correct for the profile and/or the pulley line shrink.

The mixer test can actually cause a kite to become unstable. Settings for shrunken bridles is not all even. Measuring the kite bridles is great for learning about shrink but not necessary to correct as you can just restretch. Guessing an adjustment through the mixer is not too hard if you know the correct direction ( BC shorter) to go in and that because of "the problem with flysurfer mixers" this will have side effects which can only be fixed by modding. You could measure out some bridles on the kite and that would help approximate what the correction should be. It is also possible to look at the bridles interact ,when/what becomes tight and slack, and by how much and then make changes, but that would require experience only now I am starting to understand.

[Jzh_perth]

I can confirm that Flysurfer do recommend ABCZ all even (B-0 & C-0 which is saying the same thing) for all the current kites.

I am fortunate to be able to fly all the new kites as a dealer, but also have Speed 2 and Speed 3 still in the quiver.

I find after the first 10 hours or so, the rear lines will have shrunk sufficiently to warrant extending the steering lines (knots are under the bar floats) to ensure front & rear lines are equal at full power, sheeted in.

If the kite is flying fine with ABCZ equal, then I only check every 6 months or so. After the initial 10 hour bedding in period I find things don't change much further.

If the kite is not flying well (I had some instability with a Speed 4 Lotus 6) then I start by shortening C in 0.5 cm increments. I usually leave B alone as it will automatically adjust by half as much as C. This is mentioned in the Gear Guide as the preferred method to set basic trim. As you guys all know, all we are doing is modifying the shape of the canopy (ABCZ represent the canopy in cross section) to induce or reduce certain characteristics.

Interestingly I find the Sonics are NOT very sensitive to mixer changes, and have not yet had the chance to play with the Speed 5 mixer yet. My Speed 2's and 3's are more sensitive.

I've also found the front / rear line differential to be by far the biggest factor in poor performance, and is always the first thing I check on customer kites.

Also, do swap out the pulley lines - Flysurfer state to do this every 100 hours of flying (and the pulleys themselves at 250 hours) This is a simple job and hence why Flysurfer include spare pulley lines for all their kites in the repair kit.

Definitely consider this if your kite is a season or more old !!

Happy flying !

[Mossy 757]

The problem with flysurfer mixers is the test only accounts for half of the pulley line shrink and their is no way without a mod/s to correct for the profile and/or the pulley line shrink.

The mixer test can actually cause a kite to become unstable. Settings for shrunken bridles is not all even. Measuring the kite bridles is great for learning about shrink but not necessary to correct as you can just restretch. Guessing an adjustment through the mixer is not too hard if you know the correct direction ( BC shorter) to go in and that because of "the problem with flysurfer mixers" this will have side effects which can only be fixed by modding. You could measure out some bridles on the kite and that would help approximate what the correction should be. It is also possible to look at the bridles interact ,when/what becomes tight and slack, and by how much and then make changes, but that would require experience only now I am starting to understand.

We'd agree in person, but the point I'd make is that this is not a Flysurfer problem, it's a foil kite problem. The only way to 100% know you're in tune is to measure every single bridle line. That's a lot of work, so like you said sometimes "guessing" via a mixer test gets you close, sometimes you measure from the 2nd power rib to get things right.

In my case, I just assume the mixer is a "relative" measurement and usually check at the power rib with a measuring tape and the line plan once I make any changes.

[foilholio]

What is a power rib? The attachment on the kite?

The problems with foil kites are all much the same. Other mixers are much worse than flysurfer's because of their lack of adjustments. This is though a flysurfer problem because of the way they have adjustments or designed their kites you will need to modify the mixer to fully account for pulley line shrink but also to account for bridle shrink. This is not something that flysurfer, their dealers, even Armin in an otherwise great video says, and I think to a large part because of that people find it hard to accept what I have written. I have gone against the grain a lot to use foil kites as long and for what I do with them. I have spent a great deal of time and effort to understand them. I will say flysurfer and Armin are wrong on this. I could guess well why this is like it is and design the kite or mixer so that the mixer still just only needs have C and B adjustments, but that is not the best solution. If I was flysurfer I would simply change the Rear main into the Z main and add a couple of knots on long spliced section at the bottom. It adds function and simplicity. As I said before if you can only notice day to day changes on your kite you will not be able to notice any of this. Even then when you do a mixer test it will improve things but only half what it should. When I first started with flysurfer kites they would eventually go out of tune. After a mixer test, they would never be quite right again. Change the mixer one way, they would be better in one way and now worse in another. Change it the other way now better in another way worse in another. Change pulley lines(already partial shrunk from sitting around), now almost good. I ended up playing with this mod, and then the kite was nearly like new. Later got into restretching and everything was golden. Then I started looking at the mixer again combined with my Z mod and what do you know the kite doesn't even need its bridles restretched and it's great.

All this arguing is pointless. The excel sheet is there argue with the numbers. Take a well functioning kite or even a new one and shorten c pulley line on the front 10cm, do the mixer test and tell me there is no difference how it flys.

Let me have one more go at this. I obviously didn't explain clearly enough. I will try explain it as clear and succinct as possible.

The standard mixer provides "2" functions. "MIX" ABCZ and "LIMIT B" from extending. The "mixer test" does not correct the "LIMIT B" part correctly.

[Mossy 757]

What is a power rib? The attachment on the kite?

The problems with foil kites are all much the same. Other mixers are much worse than flysurfer's because of their lack of adjustments. This is though a flysurfer problem because of the way they have adjustments or designed their kites you will need to modify the mixer to fully account for pulley line shrink but also to account for bridle shrink. This is not something that flysurfer, their dealers, even Armin in an otherwise great video says, and I think to a large part because of that people find it hard to accept what I have written. I have gone against the grain a lot to use foil kites as long and for what I do with them. I have spent a great deal of time and effort to understand them. I will say flysurfer and Armin are wrong on this. I could guess well why this is like it is and design the kite or mixer so that the mixer still just only needs have C and B adjustments, but that is not the best solution. If I was flysurfer I would simply change the Rear main into the Z main and add a couple of knots on long spliced section at the bottom. It adds function and simplicity. As I said before if you can only notice day to day changes on your kite you will not be able to notice any of this. Even then when you do a mixer test it will improve things but only half what it should. When I first started with flysurfer kites they would eventually go out of tune. After a mixer test, they would never be quite right again. Change the mixer one way, they would be better in one way and now worse in another. Change it the other way now better in another way worse in another. Change pulley lines(already partial shrunk from sitting around), now almost good. I ended up playing with this mod, and then the kite was nearly like new. Later got into restretching and everything was golden. Then I started looking at the mixer again combined with my Z mod and what do you know the kite doesn't even need its bridles restretched and it's great.

All this arguing is pointless. The excel sheet is there argue with the numbers. Take a well functioning kite or even a new one and shorten c pulley line on the front 10cm, do the mixer test and tell me there is no difference how it flys.

Let me have one more go at this. I obviously didn't explain clearly enough. I will try explain it as clear and succinct as possible.

The standard mixer provides "2" functions. "MIX" ABCZ and "LIMIT B" from extending. The "mixer test" does not correct the "LIMIT B" part correctly.

Adding a few knots or a pigtail shouldn't really blow anyone's mind. I think for all but the most rank amateurs this sort of modifying is pretty standard in kitesports.

[Jzh_perth]

I think I understand now - you are referring to the shrinkage of the grey pulley lines - the lines that the pulleys connect to, not the lines that run through the pulleys ? I misunderstood and was thinking the yellow lines. I've not had a chance to try your spreadsheet as am reading this on iPhone.

[foilholio]

Mossy that's really not a very nice thing to say, surely you are not derogating everyone yourself included? If it was the case though why does not anyone do this for flysurfer kites? Why does flysurfer not recommend it and in fact say it is unnecessary? Well they do recommend changing the pulley lines, but you would be doing that every second week to stay absolutely near top performance. I have explained it in person and shown it but still drawn absolute blanks in people. It's the age old common problem of trying to hold two contradictory facts in the one head and the one with higher authority wins and in this case it's flysurfer's. "Flysurfer said the kites have adjustments and that is all you need so well that is all you need". "God said the world was made 7000 years ago so the dinosaurs are not real". "I woke up and felt great and Pastor told me that is because of God, the pastor is nicer than you Mr Atheist , so of course god is real". Or in the case of Islam "We are all really poor and life is pretty shit but we have been killing every one with different opinions like the Imam and Allah told us would make us have better lives."

Jzh_perth I am talking about the pulley lines(yellow). If you think I am talking about something else, I really don't know how I can explain it better. Flysurfer told you the mixer test corrects for pulley line shrink this is not correct.