Appropriate length for single line flagging?

[L0KI]

Most new LEI bar systems are set up to flag to a single front line.
My question is for single front line flagging systems on four line bridled kites, I am aware that five line kites exist and that some kites are still set up to flag to both front lines.
As we all know, bridles have gotten much shorter, and a number of them no longer use pulleys.
What is a appropriate minimum length that the the bar has to go up to make a safe single line flag on a typical four line bridled kite?
I've had many older bar systems that flagged the bar way up and some that were very short and essentially the same as going suicide.
Years ago I used to hear (probably with four line C kites) that a good flagging length was at least the distance of the kite from tip to tip, which would mean that your flagging system had to go as long as the width of your largest kite for your bar system to work with all your kites.

So, how far does a bar have to ride up the line to safely flag a kite these days?

[edt]

Years ago I used to hear (probably with four line C kites) that a good flagging length was at least the distance of the kite from tip to tip, which would mean that your flagging system had to go as long as the width of your largest kite for your bar system to work with all your kites.

Yes that's the rule. It's easy to see why this is the case. Less than that you have a possibility of some loading on the far center line. If you have little kites 6m or so is enough if you have large ones 10m should be more than enough. I always put my stoppers at 10m because it's more than enough for all my kites.

[iriejohn]

Years ago I used to hear (probably with four line C kites) that a good flagging length was at least the distance of the kite from tip to tip, which would mean that your flagging system had to go as long as the width of your largest kite for your bar system to work with all your kites.

Yes that's the rule. It's easy to see why this is the case. Less than that you have a possibility of some loading on the far center line. If you have little kites 6m or so is enough if you have large ones 10m should be more than enough. I always put my stoppers at 10m because it's more than enough for all my kites.

Perhaps I've misunderstood ... given that the bar will stop when the kite has effectively rotated 90 degrees why is there a need for a stopper?

[tmcfarla]

I understand that this rule is repeated because it is easy to remember and easy to measure, but it isn't possible for a kite flagged to a single line to require a full length of the kite. First, the kite is presumably inflated, so projected(inflated) length, instead of actual(uninflated) length, is the absolute maximum length. Second, with a single center line release you are already pulling from near the center.

I haven't tested this, but I would think the minimum length of a flag-out line would be the distance from where the safety line connect to the kite to the furthest point away on the inflated kite. This would be some fraction of actual kite length and would vary from kite to kite based on the shape of the inflated kite.

[edt]

you don't need a stopper. and yeah you probably don't need the full width of a kite. if you want a shorter stopper go for it. I like having a little extra margin of error

[L0KI]

The old rule was logical and I understood why.
But with bridled kites configured the way most of them have been for the last 4-5 years, I've used about half of the old rule (six meters) on a few of my bars and it has gotten the job done. My kites are 7.5M/10.5M/13M so nothing tiny or huge.
I wondered who else thought about this and what they came up with for the correct length.
Sure makes retrieving that bar easier (with less line to get yourself tangled up in) if you decide that a relaunch is in order.
I don't care to kite in 35+ wind at this point so it's not as critical as it might be for some kiters on their 4/5/6M kites in nuking winds.
I wondered if somebody smarter than me had used bridle measurements and done some real calculation as opposed to my "that seems about right" method.

[ronnie]

The old rule was logical and I understood why.
But with bridled kites configured the way most of them have been for the last 4-5 years, I've used about half of the old rule (six meters) on a few of my bars and it has gotten the job done. My kites are 7.5M/10.5M/13M so nothing tiny or huge.
I wondered who else thought about this and what they came up with for the correct length.
Sure makes retrieving that bar easier (with less line to get yourself tangled up in) if you decide that a relaunch is in order.
I don't care to kite in 35+ wind at this point so it's not as critical as it might be for some kiters on their 4/5/6M kites in nuking winds.
I wondered if somebody smarter than me had used bridle measurements and done some real calculation as opposed to my "that seems about right" method.

I once checked the distance needed for a 17m kite without the wind flattening the kite out and it was 8m, so to allow the kite to flatten out as much as it could in a strong wind, it would be more like 9 or 10m.

[edt]

the correct length

I don't see any way to have a formula because every bridle is different. Just throw the QR on land on your biggest kite. See how far up it has to go so the furthest line doesn't have tension on it.

[L0KI]

Kite companies have done a mediocre job on many bar systems, I wonder how much thought they put into the safety release system.
Core decided that a push away chicken loop release like everyone else was not gonna cut it.
Clearly a couple companies have spent a massive amount of time on their game changing rear line sheeting systems.
BRM did really think outside of the box and I applaud Greg for that.
They waste our money year after year on the above bar swivels that don't work.
There are still systems out there that do not flag well if the kite has looped three or four times.

[edt]

I think they work pretty hard on getting their control bars right. Look at for instance the new ozone control bar. Used to be the megatron a very nice side release but they switched it to the contact. Now they knew they were moving to a push away back in 2011, so they worked on it, 2011, 2012, and some of the parts weren't right, they kept working on it, so I think it was finished in 2014 or 2015, so it took them 3 or 4 years of development, there's no question they wanted this push away out on the market immediately it just took time to get the parts right. Or take a look at the liquid force control bar. They knew they had a lemon in the 2010 CPR and went back to the drawing board to redesign it came up with a pretty wicked design in 2015, put it to market and right away there was a recall. Now, there's no question this hurt their business a lot. I can't believe they were deliberately sloppy, it's just difficult to get a control bar right. Now the liquid force control bar is excellent but they lost a lot of business with the recall. You look at north's iron heart, that was an excellent design and just how north works they are slow, even slower than other companies so they keep everything that works and just make minor design changes. Switch I think just put out a garbage control bar it doesn't work right, so in that case, yeah they just didn't care much about it and put out a crap bar. Other companies though I think they put in a lot of hours time and lots of hard work getting it right. That said you or me can build a control bar that is near perfect, well, one thing you or I would do in a control bar is buy a prefab QR. We don't design our own QR's and we don't design our own swivels. There were some really dangerous control bar designs back before 2010, for instance that liquid force control bar that would never release, the cabinrha recon that would deathloop, there were plenty of designs that were not only bad they were dangerous. I think they are working hard, why it's so hard to get it right that I can't say. It doesn't seem hard to do, but maybe someone in the industry would have more insight. I would especially like to hear from ozone about why it took them 3-4 years to design their push away release. That's a long time and I don't think they were dicking around scratching their balls for 4 years.