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Speed system / mixer test explanations

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revhed
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Re: Speed system / mixer test explanations

Postby revhed » Sat Mar 10, 2018 11:12 pm

:thumb: :D 8)
THX 4 all your time to compile this!
I am sure that on my next yet to be decided ultralowind RAM AIR, I will make "ladder knot" 1 cm spacing, say 10, extensions" on ALL 4 bridal rows, each side, between mixer and bridals for fast on the beach adjusts and test flights.
I did this only on my T E, Z, D, lower bridles and was easy to dial in, this after mixer tuned of course so A B C were close to perfect.
R H

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Re: Speed system / mixer test explanations

Postby foilholio » Sun Mar 11, 2018 12:51 am

Sorry I didn't reply to your msg revhead I will now.
Kykeon wrote:
Sat Mar 10, 2018 7:59 pm
foilholio wrote:
Sat Mar 10, 2018 2:34 pm
Adjusting Z is the easiest way to change camber. Z shorter = more camber = more lift = more power and kite flies in less wind but more drag so harder to go upwind and the kite is less stable.
Why less stable? Wouldn't it sit deeper in the window and therefore less prone to front stall?
It's to do with the torque produced on the wing from the lift. The higher the camber the wing the more it will pitch down at the front. Which if you think for a parafoil which needs tension against the bridles to work having part of the wing fly down is not a good thing. Having the wing pitch down it will tend to over fly more ,and further as well, not good for stability either. With reflex or reduced or negative camber ,ie Z more slack the torque will produce a pitch up so creating more tension on the bridles and kite can sit a little deeper, all making it more stable. Lift and drag go hand in hand so while you will get more drag with higher camber this will only occur when the lift is high which is when the kite is heavily sheeted in. In the heavily sheeted position high camber is quite stable, but it is hardly practical to always have a kite fully sheeted in so it won't collapse, especially one with possibly double the lift because of the increased camber. It's all a choice of compromises, best to use high camber in steady wind.

On a side note kites can have camber ,especially reflex, sewn into their shape. It is one of the secrets to more stable foil kites, the peterlynn ARCs ,and flysurfer triple depower or shape change.

Race kiters would be wise to have a second trimmer to adjust camber on the fly.

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Re: Speed system / mixer test explanations

Postby Regis-de-giens » Sun Mar 11, 2018 9:40 am

You can also do splices like it is the current proposal on some recent kites. 4 points is not useful. 2 on either ABC or Z is enough to complete every configurations (completed by the trim on the bar).

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Re: Speed system / mixer test explanations

Postby oldkiter » Tue Mar 13, 2018 1:36 am

On Pansh kites do you have to make new bridle sections for shortening Z, or just use some figure 8 knots on current sections??

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Re: Speed system / mixer test explanations

Postby foilholio » Wed Mar 14, 2018 3:25 am

You can make knots in existing parts, just remember it can weaken them. I detach the Z main from the Rear main , make a figure eight in the rear main and larks head the Z main beneath it. This has the benefit of giving you 3 settings for Z adjustment, the newly made figure 8 knot, the rear main C pulley line join and the rear main/rear line join. Sorry for the flysurfer jargon, just have look at a flysurfer line plan off their website the understand what the different mains are. I actually use this adjustment on all my foil kites especially flysurfers. It's actually something that you need to do to flysurfers in combination with a mixer test to restore their full depower or B extension when depowered , as when the pulley lines shrink a mixer test alone won't fix that.

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Re: Speed system / mixer test explanations

Postby oldkiter » Wed Mar 14, 2018 4:03 am

Thanks. Searched my "stuff" and found some pre-made bridle sections. One pair is apx 5cm (2 inches) shorter than Z (I think Z main...above first attachment point). So switched them. I'll check flight characteristics with the shorter Zs. Hoping for positive result!
Last edited by oldkiter on Wed Mar 14, 2018 3:02 pm, edited 1 time in total.

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Re: Speed system / mixer test explanations

Postby Regis-de-giens » Wed Mar 14, 2018 2:27 pm

Kykeon wrote:
Sat Mar 10, 2018 7:59 pm
Regis, many thanks for the post!
It's so useful that I made it pdf and I stored it in myKitesurf_info folder!
I have corrected a typo in case 3 (un-trim instead of trim) ; you should upgrade your pdf with the new Case 3 :wink:

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Re: Speed system / mixer test explanations

Postby oldkiter » Wed Mar 14, 2018 5:53 pm

Been looking at the FS Speed5 line plan. Obvious immediately that the Pansh Aurora II has a connection from Z to C through "C7". The Speed5 does not have this connection. Anyone tried eliminating that ZC connection on a Pansh. Maybe that has some cause of the sensitivity to backstalling. Admittedly a foil newbie but seems a major difference!

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Re: Speed system / mixer test explanations

Postby edt » Wed Mar 14, 2018 6:13 pm

foilholio wrote:
Wed Mar 14, 2018 3:25 am
You can make knots in existing parts, just remember it can weaken them. I detach the Z main from the Rear main , make a figure eight in the rear main and larks head the Z main beneath it. This has the benefit of giving you 3 settings for Z adjustment, the newly made figure 8 knot, the rear main C pulley line join and the rear main/rear line join. Sorry for the flysurfer jargon, just have look at a flysurfer line plan off their website the understand what the different mains are. I actually use this adjustment on all my foil kites especially flysurfers. It's actually something that you need to do to flysurfers in combination with a mixer test to restore their full depower or B extension when depowered , as when the pulley lines shrink a mixer test alone won't fix that.
Foilholio doesn't pansh use the same system of letters as flysurfer? ABC and Z?

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Re: Speed system / mixer test explanations

Postby kitexpert » Wed Mar 14, 2018 7:17 pm

Z-lines are brakes. If you have them too tight bar pressure increases a lot and kite stops when fully sheeted in and kite backstalls. Sheeting out kite flies fast, in general behavior of kite becomes twitchy.

To name this kind of setup some kind of camber adjustment is too simplistic.

There should always be some method to adjust brake tension, because it is quite a lot personal choice how kiter wants them. But if you look how well tuned efficient kite flies you won't see almost at all brakes working. That is because if they do (considerably) kite gets slower. In very low winds most essential is to get foil kite flying as fast as possible.

Even better if brake adjustment can be made separately between center and wingtips.

I remember years ago first test flight of a kite in which I had much too long brake adjustment line resulting brakes were slack all the time. However kite flied well and also looping was possible. Only real advantage of very tight brakes is downwind use or trying to make slow kite reacting a bit faster.
oldkiter wrote: Been looking at the FS Speed5 line plan. Obvious immediately that the Pansh Aurora II has a connection from Z to C through "C7". The Speed5 does not have this connection. Anyone tried eliminating that ZC connection on a Pansh. Maybe that has some cause of the sensitivity to backstalling. Admittedly a foil newbie but seems a major difference!
It is useful, because wingtip LE is already pulled 1:2. If you fix c7 there will be upward bulge in the middle of the wingtip. Drawback of that line is when it rolls through the ring it shrinks. Reasons of backstalling are much more fundamental than a single line in a wingtip.


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