the "Malabar" mixer test for large foilkites in light wind

[Regis-de-giens]

It is just that BC will always find their own balance.

That is actually what I fear : kite camber need to be imposed as strongly as possible (kite stiffness) and not too much "free of deflected" as he wish.
(Ex) Malalbar was a bit preserved of this problem thanks to the fact that A tension is always higher than Z tension (in normal ride mode, except reverse launch hence my doubt on this point from the start), hence kite was not free to rotate during a ride since : A was imposed by front line and Z was imposed by A and its higher tension. But an even better stiffness would be obtained by pulley-bar for sure.

Regarding bar pressure, lets try to put rough figures. You will get in the rear lines : 0*A + (B+C)/2 + Z, to be compared to standard mixer = 0*A + B/4 + C/2 + Z. So you will catch "only" B/4 additionnal pressure. B being in the order of 25 % of total traction (to be confirmed, depends on kite design), additional pressure will be approx 6% of total traction on an average of 20% "in the arms". So the loading in your arm should go from 20% to 26% => + 30 % in your muscles (rough values of course) . Impact of throw would then be 1/1.3 = 76% throw , so half reduction than pulley-bar but not negligible indeed. But all this reasonning is based on B keeping 1/2 of the displacement of C . But I think that since displacement of B will increase and C decrease, bar pressure will decrease from this estimation (and be even closer to standard mixer).

That is my guess, so very interesting if you can do this test...

[foilholio]

It is an interesting problem as to how it will work. I look at a mixer as providing 3 functions, depower, flight/powered and relaunch.

To depower it needs to release all the bridles but A, maybe it will keep some tension in B. The standard 421 mixer requires a lot of movement in the rear lines to get just a little in B but C and Z move quite readily.

Powered, depends on the camber you want(ignoring sewn in camber), but to me and the way I see kites tuned from new, is to have an even tension across all bridles is about the best, maybe with a little less tension on Z. Slack bridles seem to destroy a kites performance. But as well, too much tension particularly in Z can destroy upwind and maybe float/glide( well it should as upwind and hangtime are linked). As I recently played a bit with one of my kites that was out of tune, it seems quite difficult to gauge the exact best BC relationship, Z is quite a bit easier. Maybe with help , one flying the other looking this could be easier, but from the flyers perspective I find it difficult.

Relaunch. It's part mixer part kite. The kite needs to reverse itself, it's airfoil, it's towpoint. Z must become A, but on the rear of the kite. The mixer must release ABC as much as possible, well to a point. If a mixer does not have enough pulley movement it wont achieve this.

I can see my mixer providing all these functions. Setting an unusual camber will be difficult/ impossible. I think it will be good because BC should automatically find equilibrium. Now if B is meant to hold more tension than C well it wont work.. Which it might be, leading me on to bar pressure.

They way I see it, a bit from in the air and definitely from how bridles shrink, bridles hold tension in this order ABCZ. Now in flight roughly the center of lift should be 1/3 back. So you would think B carries more load sheeted in with normal riding than A,C or Z. So in theory changes to B should affect the Bar more than the others.

[foilholio]

Well I have tested the automixer (number 9) a bit now. It doesn't do anything outrageous to the kite. The profile seems smooth nothing too weird. Relaunch is fine maybe even improved. Turning is quicker and more responsive. Bar throw is significantly shorter. Bar pressure is moderately increased. The kite does seem to stall a little easier but that may be because of the shorter bar throw, but maybe the airfoil as well. B and C react much in unison. They both release and tension at the same time. Hard to see on the end of 21m lines but BC do appear to stagger a bit with C moving more than B. One unusually thing is happening with the bridle, occasionally some of the bridles mainly C in the middle will lose some tension, while the adjacent bridle in B will remain tense. I explain it as all of B is balancing against all of C, some parts of the kite will fight more than the others, leaving others doing very little.

I had a play with changing the camber on the mixer and it works in flight much as you would expect, but the wing is a little different with B being more tensioned in a reflex profile. This gives a different airfoil than normal.

Partway conclusion is that it shows great potential. It has the potential to minimize and simplify the mixer. The BC Pulley line may not need to be very long at all and the BC relationship will never need adjusting. It will work better on kites with B further back and a closer BC grouping, like the A15. As such there exists the possibility to design a kite to use it better.

I will test further!

[Regis-de-giens]

@foilholio: it seems to bring good advantages, cheers !
In fact I was just thinking of another evolution that you could test from your mixer: just remove this new B&C pulley ... Indeed I would bet that tension partition between B and C remains approx the same during the bar throw, hence maybe this pulley is almost not turning at all ! And in that case you will also gain in rigidity , simplicity and weight ... and keep approx same bar increased pressure.

Ps: I had done something "similar" on my speed2 19m : connect B to A and remove the 2*twin pulley that "Kiter_from_Germany" presents in its second sketch. In theory it increases the camber (hence power) when sheeting-in and decrease the camber (less power) when sheeting-out, so all good (even if on B only and not C). I cannot tel you if it is exagerated or if L/D ratio is significantly affected, since it is on my single skin under develepment for which I fight against weight ...
( But effect is on the contrary decreasing bar pressure on my 19m).

@ Kiter_from_Germany: sorry i had missed your last message; thank you for your feedback and reflexions. I am affraid that adding the pulley as you propose in your second sketch (like for speed2 mixer system), will decrease the initial interest of your proposal without even guarantee you will reduce AoA (depower) when sheeting-out the bar. And what "could" happen is that when the kite start backstalling for any reason (light wind), and start flying backward, C tension could increase, A could decrease, so kite will backstall even further with no ability to depower up to the contact with the ground.

[foilholio]

I am pretty sure BC pulley moves. But I will try fixed, maybe on one side of the kite so I can compare.

[plummet]

I'm going to gate crash your technical discussion.

So I have a 12m chrono. It has heaps of aoa at the bar. Crisp turning and generally flies well. I don't feel a need that I need improved turning etc. I really enjoy the back stalling ability. Its particularly useful to get a soft landing from height. Let the bar out on the descent to speed the kite up then bar back in hard and redirect on landing.

It gives you a soft landing every time. That's particularly useful for my landboarding where a stuffed up hard landing = broken legs.

So... Trimming a foil to fly like a lei would reduce its performance in my mind. No longer would I have the safety of that back stall flair on landing.

Back stalling with turns and loops are also usefull on occasion when running towards the kite. Stall it deep in the window and then run directly at it. You wont get the collapsing like it might when outside the window.


On the 12 I feel I have enough aoa and turning ability within the current race bar settings/mixer. The other day i fly an 18m chrono. With the 18 i didn't feel as though aoa or turn response was even close to what I needed. I ended up reaching up the leader lines in an attempt to get the kite to turn.

So.... My thought is maybe your malabar mixer idea would be more suitable to larger foils like this 18m which definately could have done with alot more input that what the current bar/ mixer could provide.

[foilholio]

The Malabar wont relaunch . You referring to the Automixer? You could use a pulley bar but I hate them. Losing the chicken loop helps heaps as well.

You have any ideas as to pulley arrangements?

I have been thinking of trying a 6line setup with 2 lines running to the front of the C pulley lines, rider end has an extra trimmer. End result is mixer can be changed while riding.

[Regis-de-giens]

i have been told that some paraavis kite have this kind of mexer setting with additional lines (but never seen it, paraavis are not so common).
plummet, regarding your chrono 18 lack of manoeuvrability, and since malabar does not relaunch apparently, i advise you to test the pulley bar (also called turbo bar). I was very pleased during almost two years with such a bar on my 22m aurora, and no relaunch problem of course.

[plummet]

i have been told that some paraavis kite have this kind of mexer setting with additional lines (but never seen it, paraavis are not so common).
plummet, regarding your chrono 18 lack of manoeuvrability, and since malabar does not relaunch apparently, i advise you to test the pulley bar (also called turbo bar). I was very pleased during almost two years with such a bar on my 22m aurora, and no relaunch problem of course.

That 18 was a demo kite. I hated it.

I'm sticking with my 12. I don't need anything smaller.

[Kiter_from_Germany]

@ Kiter_from_Germany: sorry i had missed your last message; thank you for your feedback and reflexions. I am affraid that adding the pulley as you propose in your second sketch (like for speed2 mixer system), will decrease the initial interest of your proposal without even guarantee you will reduce AoA (depower) when sheeting-out the bar. And what "could" happen is that when the kite start backstalling for any reason (light wind), and start flying backward, C tension could increase, A could decrease, so kite will backstall even further with no ability to depower up to the contact with the ground.

Hello Regis,
thanks für your remarks. After all I come to the conclusion, that the line connection points of modern kites are hard linked to the 1:2:4 mixer system the maker supplies in modern kite design.

If we summarize, that we can't move the steering line force induction from Z to C cause of bad relaunch performance and can't move the leding line force induction from A to B, because of profile collapsing danger, we are at the end, I think.
So I stop in thinking about tuning new kites, perhaps I find some elder ones to tweek a little with the good ideas we discussed.
So thanks for you all, see you at the spot!