Sonic II ...Mixer issues ?

[Carlos_C]

Bit of an odd one here.

Bought a nearly new Sonic II 13 mt. Mixer tested - went out using the bar from my Lotus 10 and the kite flew perfectly -

Yesterday - rigged up using the bar from my speed 5 6mt - with the leader on outside of bar as per instructions.

On launching the lips of the kite would not open....I could force them open by powering up - but they would then immediately close...I did a quick check of the mixer and all seemed ok...but was on beach with another kiter roped in to help (who was itching to lauch their kite) so won't guarantee how well it was done.

I'll test fly this week on the local playing fields - but really puzzed how a kite can go so wrong after 2 weeks in it's bag. Tips tucking would mean B's and c's too short ??

[Adventure Logs]

Sounds like a bridle twist. Nothing could happen that quickly that would explain such a change in behavior. Another reason why it’s a great idea to keep your bar/lines attached.

[Mossy 757]

Might be a bridle issue, but I'd just suspect your bar is wildly out of tune. Think about it like a maintenance professional:

Part A and Part B work together. (Kite + Lotus bar)
Part A and Part C do not work together. (Kite + Speed bar)

Part C is the defect. (something about your Speed might account for why the kite works well with an out of tune bar. The Speed is pretty forgiving on mixer tune so this isn't really shocking)

Double check that your flying lines and steering lines are equal length with the trimmer fully-released with the bar all the way against the chicken loop. I suspect that you'll find that the rear lines are shorter than the front lines by a meaningful distance, that kind of tip curl is easy to induce with a ton of backstall which is likely your problem.

It might also just be a bridle/mixer twist, but I assume you wouldn't post to the forum without thoroughly inspecting that

[Carlos_C]

Nah - checked that -

but will test in the park - we have a few light wind days coming ahead. and yes I normally never change lines....but the kite was too good a deal K/O.

Though the most bizarre case is I have a pair of 2007 fuels......7 -9 - flew them on the same bar - no probs for a year.
Didn't use them for 6 months - rigged up and suddenly the back lines are 6 -8 inches too long......lots of head scratching went on there.

[Mossy 757]

Nah - checked that -

but will test in the park - we have a few light wind days coming ahead. and yes I normally never change lines....but the kite was too good a deal K/O.

Though the most bizarre case is I have a pair of 2007 fuels......7 -9 - flew them on the same bar - no probs for a year.
Didn't use them for 6 months - rigged up and suddenly the back lines are 6 -8 inches too long......lots of head scratching went on there.

If it is a problem in the mixer, then what you're looking for is C (and by proximity B) to be too long. The cure for an old, shrunken bridle causing a back-stalling and slow-turning kite is to relax C and B. The cure for a tip curling, overflying the wind window, collapsing kite is the shorten C and B. In this case, if you do the mixer test and the B and C are shorter than A and Z, I would not adjust the bridle as you're likely dealing with something else that's the problem. If you find that B and C are longer than A and Z, then I would shorten them and then test-fly.

[Breze]

Hi Carlos
If the wind was stronger on your second launch, then i guess that you had problems to fully inflate the Sonic. Then the ears shake and collapse to the middle. The Sonic needs once to be be full of pressured air, then it stays stable. Try to oversheet by pulling the leaders 20-30cm below the bar then the Sonic pops opened. This is a bit antiintuitive in stronger winds and can be scarey. Just my guess, hope it helps

[Breze]

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[Breze]

Powering up is not enough with normal bar throw

[foilholio]

Sounds like a bridle twist. Nothing could happen that quickly that would explain such a change in behavior. Another reason why it’s a great idea to keep your bar/lines attached.

Most likely this or a bar trim issue.

Tips tucking would mean B's and c's too short ??

No the opposite, too long and at the tips where it is happening. Try extending Z 5cm. Otherwise long mixer test or full mixer test or just guessing at adjustment on the tip area to reduce camber. Extending A there is a straightforward solution.

If it is a problem in the mixer, then what you're looking for is C (and by proximity B) to be too long. The cure for an old, shrunken bridle causing a back-stalling and slow-turning kite is to relax C and B. The cure for a tip curling, overflying the wind window, collapsing kite is the shorten C and B. In this case, if you do the mixer test and the B and C are shorter than A and Z, I would not adjust the bridle as you're likely dealing with something else that's the problem. If you find that B and C are longer than A and Z, then I would shorten them and then test-fly.

"A" shrinking at the tips is the main cause of them collapsing. It only takes 1-2cms there to throw the camber way out. You can easily observe over cambering of the tips by just looking at how much they are pulled in comparison to the rest of the kite. Older foils will tend to overcamber the tips a lot. Having a wing highly camber it's tips reduces it's performance heaps, though it increases the turn speed. You actually want washout or reflex on the tips for the highest performance so the opposite of the tips being arched down but instead being curved up.

[twig]

I have a Sonic 2 15m that i've been trying to trim alot.
The problem was that the whole A level was much longer then all other bridles. The amount of Line in the mixer I had left to change B + C with wasn't enough to get the kite at the original settings. I was measuring all the bridles and calculated through the lineplan where all of them should be compared with each other.

Then i started to do half knots at all connection points (but mainly a level only) to try and get closer to original trim. After that the kite front collapse and behave really bad. I dont understand how this should be done really.
Ive but way too many hours to try and get this one right.

What i would like to know is, between wich lines in the lineplan should you add Line to 'extend z'. I Guess thats what i should have done instead.