Power Kite Forum

True 5th line for arcs

Demoknight - 20-2-2014 at 03:44 PM

I wonder why PL has never put a true 5th line on any of the arcs. It would seem that a 5th line connected to the front center or rear center of most modern arcs would be much better than the current 4.5 line setup in terms of resetting, and nearly the same in terms of total de-power. I understand that the 5th line would have to be a good bit longer than flying lines to allow the flex of the kite, but why has this not been done before?

Demoknight - 20-2-2014 at 03:46 PM

It just seems to me that it would virtually eliminate the need to walk your lines every time you pop the safety. Most people that use arcs over water unanimously agree that resetting after using the safety is basically impossible out in the water, so best to self rescue and haul it back to the beach to walk the lines again and start over.

ssayre - 20-2-2014 at 03:55 PM

Hey demoknight, I can't answer your question but how do you like your arc? Do you buggy with it? What is the wind range you use it most in? Just curious I plan on getting one later on.

markite - 20-2-2014 at 04:03 PM

Yes you are right that the cleanest way to land an arc is have someone catch it. if the wind is light you have options to back down and carefully flag out but under pressure that bar will often slingshot through lines and i've had the newest set up snag with a nest of line several times in the winter as the bar slides away on the snow.
The biggest thing is kite structure - if you ever look at an arcs construction the cells themselves do not have a lot of additional reinforcing they need to distort to the curve and flex of the arc shape and also flattening out. the lateral strain on the sail is taken up by internal webbing and it is fixed in some areas and floats in others. If you imagine going to a 5th line in the centre there are times when there would be a short but incredibly high amount of pressure before the kite would flag back - it does not have the supporting structure of an LEI to distribute stress and bridled foils have multiple bridle points and re-enforcing to take the stress at moment of flagging. You would need to do quite a few things to change the structure of an arc to make it 5th line flagging. De-powerable foils collapse when flagged to a middle line - LEIs have the semi rigid air frame and supporting bridle. An Arc does not dump air, think of it like making balloon animals as you fist the centre of a fully inflated kite and again a way of distributing stress that does create damage or change the flight characteristics. Some people have played with extra lines here and there but many abandoned. PL tinkers with many ideas and perhaps it was something that was played around with but never successful?
The first generation arcs used to have a trailing edge hem binding material - that would be similar to the need to reinforce the trailing edge to add a line - but that material would shrink after getting wet and it was causing trailing edges to tighten and cup and change flight dynamics so now everything is simple and clean.
the universal answer when friends ask me about what to do after crashing .... don't crash.

PHREERIDER - 20-2-2014 at 06:30 PM

Quote: Originally posted by Demoknight  
It just seems to me that it would virtually eliminate the need to walk your lines every time you pop the safety. Most people that use arcs over water unanimously agree that resetting after using the safety is basically impossible out in the water, so best to self rescue and haul it back to the beach to walk the lines again and start over.


i have not had experience like this, i have used arcs on land and water since 2008 and 1000's hours on almost every series made .
arcs are simple 4 line kites front line safety sets up the kite for relaunch when flagged out, adding a 5th only adds to line management and rotational entanglement ...plus heres the holy crap reality part, it would start spinning so violently you have to let it go. as soon as tension hits that 5th line kite will try fly folded back , and u would not be able to control it.

the drag from the line alone could trigger a luff inversion.

the control point of arc kite is FRONT line , not center of kite like tube kites i think mark mentioned that rigid airframe thing.

the only time i swim an arc in a line has broken....and hitting the safety means kite is ruptured critically and not relaunchable and salvage would be deadly.

i learned on c-kites with 5th lines and they work! saves a mountain of swimming for sure. hope this helps your wondering.

Feyd - 20-2-2014 at 07:22 PM

I'm with Phree on this one. And as I think Mark illustrated ARCs by design don't lend themselves to that type of system. Some flavor of bridle would have to be introduced and if you start putting bridles on ARCs you've completely destroyed what makes ARCs awesome.

I personally do not use the Peter Lynn bars in their stock configuration. http://youtu.be/cCCzIJ3iKGg I like consistent flag out with none of the mess. Also easy relaunch and ride.

I still prefer stalling and rolling over to clamshell instead of popping the safety. Takes some practice though.

Demoknight - 21-2-2014 at 08:57 AM

I do stall and clam or have a buddy catch my tip to land typically. I have only ever needed to pull my safety once on my Charger2 and that was because I was yarded 30 feet downwind by a freak gust. Steady 18mph wind all day and the random 30+ hit and I had the trim let out most of the way while standing static talking to a fellow kiter. Tuck and roll and hit the safety. It worked great, but I had to walk the lines because it spun like crazy on the flag line in the air before it finally landed. I have only ever gotten a successful relaunch once or twice after using the safety. I may end up looking to bar mods like Feyd said.

Typically, once I put the Charger up, it doesn't touch the ground again until I am packing to go home.

@Ssayre: I LOVE my arc. I will say that it took a while for me to figure out what works best to solo launch and land. I love the way the kite feels in the air, and it is just a floaty dream to jump with. I use it as frequently as I can in the buggy, and it has a HUGE wind range. A 12m Charger2 is damn near a one kite quiver for my local spot. I can get rolling in the buggy in 12+, and I can ride with it all the way up to the upper 20s. In terms of fixed bridle equivalent, I would say it covers everything from about 6.5m down to 2.5-3m. When the wind is too rough for my 8m Toxic, I reach for the Charger. The only drawbacks to arcs is maybe an extra 5 minutes of setup and breakdown compared to a open cell foil.

carltb - 21-2-2014 at 03:10 PM

id just like to add on a safety note.
on the newer nav bar with the v and not the y front lines.
if you do a lot of rotations during your session and spin the chicken loop to untangle your front lines, the mini 5th line can get twisted. the solution is to unclip your leash and untwist the 5th line inside the chicken loop until its free again. if you do a rotation on every jump then youre going to have to do this a couple of times per session but if you only do the odd rotation, then it shouldn't be a problem

BeamerBob - 21-2-2014 at 03:14 PM

Anyone have a video of this "stall and clam" technique? This would be handy for me. I can't see how to get the stalled kite into the clam position if it's powered up. In many conditions I'd be timid about trying to stall into the power zone, but lots of times it would be ok and nice to avoid flagging the kite and it's mess. I'm again rethinking that Feyd's safety system has possibilities for me.

Demoknight - 21-2-2014 at 04:25 PM

You fully let out the trim, so it is fully powered, and sheet the bar in all the way to stall the kite. Steer it slowly down and turn it just as it gets about a half wingspan from the ground and it should close up tip to tip once it touches down.