I'm a little surprised there hasn't been a mention here following a recent arc users discussion about tip clapping on PL Chargers. It's something that not everyone experiences and it could be on different sizes under different circumstances. I've got to hand it to Tungsten for putting it out there and doing some mods that seem to be a fantastic solution in my mind. Others gave input and contributed in many ways - some are also on this forum.
First off there was a brief identification of the issue, trying to define when and how it happens and then the experimentation in a solution. Here are a few points copied from the discussion:
-hand claps are luffing wing tips. What I've seen when it happened, only one side luffs, not both simultaneously. Kite spins.
-I never had problems in constant winds
-gusts are not triggering the hand clap, but shifty winds / rotors / turbulences do
-under inflated kite / wet kite is prone to clap
-claps appear mostly when the kite is mid window, never had it at the edge of the window
-on the CH, wing tip profile thickness was reduced to 18% of chord, compared with previous models where it was 20%. The lift in the wing tips is reduced significantly.

Next there was some collective input and people like Chris (Feyd), Carl and others talked about pros and cons of the high Y split of the Nav. bar. Also notes about tension setting on straps.

Tungsten then noted his thoughts on the wingtip:
-I assume there's enough reflex in the profile, beause pulling in the tip adjusters (which enhances reflex as a side effect) does not seem to influence the hand clapping
-What I want to try is enhancing the tip profile thickness by shortening the front and middle strap, thus making the cells bulge. All 3 straps are sewn onto the canopy one cell above the zipper cells, so that would affect the wing tips only, which seems where the problem is located.

Finally his result/comments from this mod on performance:
- The good news is, we seem to be on the right track. Had a 4 hour testing session today, CH12, 15-20kn.
- I installed adjuster buckles on front and middle strap in the tips. For a start, I shortened the middle strap in both tips, and boy did that make a difference. It takes only a little bit of shortening to have a huge effect, because in order to have the top and bottom skin bulge an extra 1,5cm (that would be 20% thickness), you need to shorten the strap by 2mm only per 25cm wide cell.

I started with shortening an exaggerated 5cm per side, and the kite flew like a Venom. Super stable, slower turning, far more auto zenith. Went down to 3cm and then 2cm per side, and the kite flew more like the SYN. Still very stable, but more lively.

At 2cm I tried to hand clap the kite on purpose with everything I had: I rocked the front line hard making the kite wobble, the wing tips changed AoA by 20 deg. inward and 20 deg. outward, but it did not clap. I tried to launch it badly inflated (5 upwind cells had no air and were lying flat), and it launched nicely and did not clap; I dipped it in the drink, wanted to leave it there to get it really wet, but without even touching the bar, it came up again in 15 seconds, and did not clap.

I still have to further play with the straps; I guess somewhere at 1,5cm might be a sweet spot, and I'll fine tune the kite with all the other configs to have exactly the feeling I like. This may take a time as it depends on good winds. But I can say that much already, the answer to the clapping issue is in the tips, and the middle strap is the screw to adjust things.

and final comments:
I had another 4 hours today to play with the CH12, and it is sweet now. A little under 2cm shortening per side, and all the other straps loose
The buckle is sewn onto the webbing exactly like the original adjusters, just take a look at your kite's adjusters inside the zipper cells, and make a copy. Only difference is, you put it on the middle strap. You get those 1" buckles and 1" nylon webbing in any decent sports shop. You roughly need half a meter of webbing per side.

The 2cm shortening per side is for the CH12 and my personal liking. You have to figure out other sizes for yourself. I would assume CH15 is a bit more, CH10 a bit less than 2cm.

A buckle comes in handy to figure the right measurement and be able to change settings, i.e. for a beginner you might want dumb the kite down by shortening a 5cm per side, if you are ready for a kitelooping session you would shorten only 1 or 1,5cm per side. The more you shorten, the more "old arc" characterisics you will find: more pronounced auto zenith, slower turning. The power and grunt of the kite remains the same though.

So that to me is a really nice solution - a way of fine tuning to your personal preference and it sounds like it could be something to play with to slow down the turning speed on what some find to be small twitchy sizes. I'm planning on playing around with a combination of some bridle mods I have plus this strap mod on one kite just out of interest. Discussing the protos for future twinskins related specifically to something like a next generation Phantom, if the kite is designed to accommodate this adjuster it might be the perfect thing for those times in a buggy when we don't want the fast turning speed of the newer generation designs.

.....long post but I think some of you might find it useful

Mark

I know rhe dutchies modded the vpc for the 8m to slow it down. Keep in mind they are using it in 45 plus knots of wind. Ill talk to jeroen and see if I can get some photos

Thanks Mark. I had given up that a Charger would ever be in my quiver, with the tip clap and zippy turning. I DO however envy a 19m for water use and the ability to tune out the tip clap is something that makes me wonder if a charger or C II might be in my future. I'll be requivering in the next 9 months to be ready for water time next summer in this desert heat. Maybe I need to start paying attention again over at arcusers.

I admire guys that have enough knowledge about how the kites fly to imagine how a certain change might affect the kite's flight. Then fiddle with it a bit and know which way to go with it.

Speaking of that, has the kites designer given any input into the solution or has it just been guys like tungsten and Feyd pulling the strings?

excellent, i have done the same to my venom I , kind of half hyper mod on #1, #2 straps. 20mm a strap

definitely adds wing tip profile bulge esp. under load.

easy and reversible, even better!

VERY NICE!

I'm starting to wonder if these guys using the chargers actually fly them correctly in the first place. I've never had trouble with tip collapse on my chargers. I'm using the 12 and the 19 and I had owned a 15 too. I'm also wondering if it is the smaller sizes. I'd like to watch these guys actually ride and see the conditions that they are using to see if its the weather or if they are using their gear correctly. Now I know that every kite manufaturer has a few defects on kite models when they first come out so i'm not ruling that out. i'm just curious to see what these guys are actually doing.

Feyd works directly with pepijn on prototypes and he's constantly riggig stuff up to see what works best. I wish he could watch these guys take their kites out and see what they are doing. He'd know best what is happening. I see a lot of guys flying smaller arcs in not enough wind. I think that gives them some issues especially when the wind lulls.

Mark, if you ride with those guys that are having issues do you think you could record some of their riding and send it to me? I trust your judgement since you know how to use arcs

Some of the people involved are long time twinskin users and they are the guys that have come up with many of the mods all the way down the line that VO has worked into subsequent designs. I haven't had any real issues with tip clapping other than underinflated launches where a tug on the lines opens it up. however one 15 I passed along between friends - that flyer says he has a problem with it. He is very well known for trying to fly in the worst conditions - turbulent winds etc. He is going from using a Phantom and and a well worn Vortex to the Charger and I've been back and forth with him for a couple of months on it - flew fine for me when it was up, but that one a bit more tip clapping than I would expect on the launch. So the notes Tungsten said that it doesn't necessarily happen in high gusty winds - more of turbulent winds with rotors etc hit home. I can see the thinking in the reduction of the height of the profile reducing wingtip lift - on the flip side this where we get turning speed - so any lateral push on the wingtip could generate a clap.
Some people experience it more than others so to me it sounds similar to flying a race foil - you need to adopt your skills, some people will find race foils twitchy and luffing all the time in certain conditions. Same with the Charger, recognize the days when you will more than likely get those conditions and adjust.
I think it was Pitu that was experiencing a tip clap mid way through throwing loops on an 12m (edit: copied his remarks below and Tungsten's reply)

"I thinK the Y line are the problem.. also my super stable Venom 13 collapse with navigator bar.
My kites collapse while performing big kiteloops where the speed is very high. they close in half when I gain the maximum pull at the maximum speed."

"Pitu, yeah I can figure the Navigator bar adds to the problem. If you have inherent instability built into the wingtips, loads of things can trigger the clapping. Must be an interesting feeling to have a kite clap on you half way through a kiteloop over land"

If you get a chance read the whole thread on the arc users forum, Chris talks about using a bar without the split to open up the kite and most discussion is about bar and strap set-up whereas the mod to adjust the profile for lift makes perfect sense.

here is a link to to the thread: http://www.arcusers.net/viewtopic.php?f=4&t=595&sid=...

For my friend that has the problem rather than trying to tell him to stop doing the 2 hr drive to lakes on bad days it's best to find a solution to adjust the kite to bring back some of the old stability that he is used to. Remember the video earlier this year (or in the winter?) of a guy surfing and the kite constantly collapsing, aside from some other issues of strap setting and line tension etc that video was probably the case with most extreme example of it - Kami had even brought it to this forum for discussion as well as on the arc users

http://www.powerkiteforum.com/viewthread.php?tid=16759&p...

first event for me with the clamming thing.

http://www.powerkiteforum.com/viewthread.php?tid=13543&p...

the wind influence? initially i thought it was the wind quality, but time proved differently. and i had previous session by far worse quality wind.

that was about the 200hour mark on that unit, and after that, it happened too frequently for my comfort level.

glad for a solution now, but at the time its not the kinda info you like to hear about a new unit much less have to initiate.

the lycos syndrome

hmm, mark thats really interesting. I do remember the video of the kitesurfer having the issues. I know there were a couple chargers that had a leading edge defect, but i know vliegerop took care of them and got them fresh kites. I just wish I could see video of this guys issues. I can get that info strait to the designer himself to help stop any future issues if this is a kite problem and not someones ability level/ experience. If you could get your friend to film his issue i'd appreciate it. I can look it over and send it to PLP to check it out.

It seems so crazy to me because some people have never had any issues with the chargers, yet there are a few people who have big issues with the tips. makes me wonder if one batch of kites had some sewing issues from the factory. I know PLP visits the factory to make sure they are following instructions properly.

If you hadn't posted that about someone having issues, i wouldve thought it was a rider who had no idea what they are doing. I know you know the arcs well enough to make a good call, but now i want to see whats going on for myself. ive only ever had one issue witha charger, and that was when I had a tangle in my vpc that caused a spar to snap in half when it powered up. So I just felt skeptical about this problem. but I did see the vid of the kitesurfer, and in his photos it was obvious there was a problem with a bubble of fabric on the leading edge.

Keep me posted on whats going on with your buddy.

I've only flown my 15 a few times but it tip claps on every launch - more or less ... I'm notorious for getting impatient and launching under-inflated though :D

First launch of a Charger ended in a bow-tie mess then a crazy fight to get it up on the next launch ... bit of a shock. The following occasions it was less of a trouble. It was fine once it was in the air and hasn't yet clapped while flying. I did have the straps set to how I liked the Synergy though ... I've since changed to all loose.

The 19 I've only launched once but it was under-inflated and it light wind - I had to pump the center-lines to get it up :D so perhaps no chance to clap tips. I swear, the wind was only 4 to 8 knots at best and I'm VERY impressed that it a. flew at all and b. pulled as much as it did. Which leads me to think it'll have a lot more low-end than the 19m Synergy.

My personal opinion is that the wind isn't the problem, it's the build-quality or -accuracy ... I'm betting the design is pretty tight with not a lot of margin for error. 2cm tuned on the strap, over the span of the kite must be a very small percentage ...

When talking about wingtips and thickness of the profile being reduced to from 20% to 18% of the chord that does make quite a difference in flight characteristics. Many race foils have a very thin profile and as soon as there is any drop in pressure or even turning when in some cases you stall a wingtip or cause it to rotate backwards that wing tip will be the first point of loosing pressure and will luff and collapse. So on the arc the wingtip changes shape as the kite flexes in and out and sometimes the you can see the straps really start to flatten the tips down. Change the thickness to reduce the lift (which in the Charger I'm guessing they were trying to do to speed up turning) and then you have a tip that could become susceptible to clapping - but if it doesn't happen on all kites and only under certain conditions that would lead me to believe it's such a fine line in performance changes by stitching that profile a little on or off the line.

For the 15 that a friend is struggling with, it was originally owned by another friend that had no problems. Now passed along to another friend again through me, the second owner is describing problems of tip clapping. Knowing he had shown up to fly when other friends were telling me it was really weird and shifty winds I chalked it up to the wind. Got him to come out to a sports field to go over everything and it was a really gusty day standing on 1 of 3 connected sports fields surrounded by trees, lights, stands, berms, and all kinds of turbulence producing obstacles. The kite was definitely clapping on launch and squirrelly as hell but once it was up I could fly it fine despite the fact I could feel the wind throwing the kite way past vertical and drifting and then cross winded etc. I told him I thought the kite was fine when up and i know that field to be one of the worst places to fly and I don't usually take anyone there, I keep it as my personal dodge of danger and death place to ride a buggy once in a while. Next outing a friend reports offshore and gusty east winds and this fellow shows up with the 15 Charger and then next day again tells me of collapsing and inverting and spinning issues. So I'm sure a percentage is him not being used to that kite and going out in bad conditions - but he is also a long time arc flyer making a go of primarily using a Vortex 17 in snow and on water no mater what the wind conditions - a one kite quiver (he has a Phantom 12 but rarely uses it). Bottom line is I think he just needs a very reliable, less aggressive kite and if the tip adjustment brings back some of the old stability and auto zenith etc then it's a welcome mod to make him happy and less worry for me trying to keep him happy without trying to tell him he's making bad decisions.

I'll install adjuster on some kites to play around with just to see the effects - my personal sizes I haven't had any problems but I really would love to have the option to turn down the turning speed on the smaller sizes when in the buggy and speed them up when going on skis in a white out.

AD72 has video of me getting yarded by the 12 Charger that rip sent around. I gave him the clear to release it's privacy setting to see if you wizards can either tell what I'd done wrong or what I could've done. It was a higher wind gusty day that should've been great for the 12. I'm guessing 20-25. I flew it another day in light winds and didn't have any trouble with it and was throwing it around everywhere and making power doing so. I probably had 40-50 hours on arcs at the time with the 12 and had never had tip clap on one from my experience flying venom, 13 and 19, phantom 15 and 18, synergy 12 and 15. My only trouble on any other model was due to rushing launch with underinflation, or wildly crazy gusty and direction changing winds. Hoping for a solution.

The only AD72 I found on YouTube had 2 movies uploaded, one called "The Life of Pie" link?

Mark that is so good info. It seems like the people having the most trouble arent' used to the amount of precision and fine tuning that the charger presents. I can understand those who are less experienced with arcs having trouble with the charger if its one of the first twinskins they used. I try and tell people that the trickiest part about an arc is getting it inflated and launched. lots of backline tension!

Link fixed

This was the pass the Charger 12m. What happened to that one? It would be interesting if others got the clap from it.

Quote:

It would be interesting if others got the clap from it

yah that Charger was with so many people I wouldn't be surprised what you can catch from it :embarrased:

I had no clapping issues on my day with the charger12. It was a dream, considering the conditions I was flying in.

"This video is private"

Yet to ever have my 8, 12, or 19 clap... have had a many sessions on each.. but of with wear and tear it ever becomes a problem... nice to know there is a solution. I find just by paying attention to the wind speed and adjusting which knot I hook up the front lines to makes a difference as well. If it's gusty or really strong, I go for the ones closest to the kite.

That should make it worse, taper - the idea being that rear-line tension is important to keep them under control.
Really sounds like there's a bad batch floating around eh ...

Can you see the video now?

Nope. Tells me it's private when I try to play it

Ok try it now.

That works

I don't remember any of my kites doing that ... just on launch ...

Looking at Bob's video the first thing that I noticed was the kite was underinflated prior to launch. And judging by the lift you got while a the zenith the kite was pretty well powered inspite of it's size and it's being trimmed.

She launched okay but the vents may not have been open enough to achieve full internal air pressure. But the windspeed may have been able to compensate for this to a point. If the pressure is too low the kite would be more vulnerable to wind shifts and holes.

And a wind shift is exactly what it looks like you had there. The kite responded exactly in that manner and you can clearly see the wind direction on the ground in the grass. As often is the case with a wind shift you got a temporary increase in wind speed. Your kite began clapping and dropping deeper into the power zone until finally you were able to open her up at the worst possible time. The result was being yarded.

That's my assesment without looking at it too closely (11:49pm here now).

When I used to expirience tip clap the best method for me was to muscle the centerlines. Yard them hard to the hip and sometimes hold sometimes quickly release depending on how the kite repsonded. My goal was to get it to open one wingtip then I'd be good to go.

Good video. Glad you had the helmet.

I've watched this a dozen times at least. I did notice that the wind did change direction because the kite opened up over at the edge of the window because the wind hit the top of the kite. I can't see the lack of inflation, but with my lack of charger experience, maybe so. That was the only tip clap I had with 2 sessions on it and the first day was light wind for a 12. I was whipping it around everywhere that day without issue.

Without a doubt Bob knows how to handle an Arc. I remember the first time I saw the 15 Phantom go up and I though man that is a big kite for this wind. I was flying a 7.5M Apex. The camera is good for catching those moments you wish you could re-run and figure out what happened and learn from experience. I am going to have to edit together a kitesurf jump-n-crash video. I have lots of that pov footage.

I like the new avatar Feyd



Imperial

Over-inflated on launch in my book

... did a bridle snag?

To those who modded the strap - was it easy to stitch on? with a machine?

Quote:

Originally posted by Kamikuza Over-inflated on launch in my book ... did a bridle snag?

it was all good till that wind shift! It couldn't have wanted for much more inflation the way the wind was blowing that day. Maybe it dwindled a bit before I launched.