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As I mentioned in another thread, I have a heap of material left over from building 1830 F-arc's. The f-arcs are made from good quality chikara ripstop and it is too good to just throw out, so I decided I needed to put it to good use.

I have been playing with Surf Plan for a while now and although I can get a design that looks good, I have no idea if the design will fly or not. Then one day looking threw some old archived websites, I found a link to the surf plan design specs for a 6m p-arc. P-arc (P=parallel) was the original name of the F-arc, but was changed before release because Parc backwards is crap :D 

SurfPlan Download

P-arc base.sle

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anyway, I decided it was worth giving it a go since I already had the material. So I got the plans printed out on A0 paper and set to work.

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first thing I had to do was unpick every seam on the remaining sections of 16m f-arc, which took a lot longer then expected.

next came the marking out and cutting. Because I was working with material that had been folded and crushed, rather then off the roll, it was a nightmare getting it to lay flat to trace the outline on to. I had to flatten an then clamp the corners to the table. As well as the outline of each piece surfplan also allows you to add waypoints so everything can be aligned after being cut.

I used a hot knife to cut all the pieces out to make it a bit quicker and stop the edges from fraying.

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i then used double sided tape to stick all the pieces of the top and bottom skin together for sewing. The ribs were too difficult to stick in place, so they were just aligned and stitched as I went. (A walking foot attachment from eBay makes sewing ripstop sooo much easier)

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The surfplan design didn't have spar pockets, so I made them from some 50mm webbing and stitched them to the end cells. 

I also added internal front and rear straps of 25mm webbing, similar to the more modern arcs. Like the modern arcs, the rear strap has adjustment for the middle 5 cells and wingtip 5 cells. I also made the front line adjustable at the middle 5 cells, in case the kite was prone to backstall.

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And the finished product.....

flat area: 6m

wing span: 6m 

AR: 6.0

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I estimate it took about 100hrs, cost $150 and countless ?

 

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  • .Joel featured this topic

Outstanding work!!!!:ok:     I'm amazed at what you come up with.

It's a credit to your determination to achieve fella. Or more to the point, not waste good materials.

This should be a great high wind weapon. Bloody well done.

Bet there is no wind for a month now.

 

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1 hour ago, Kamikuza said:

Looks great, good work. Always wanted to do that but never had the time or inclination :D

I seem to remember reading on the PL blog that the F-arc was so named because the first time he flew it, he was like "Farc!" I wonder which story is apocraphyl . . .

Seems we are both right :D 

http://www.peterlynnkites.com/news/0112news.htm

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Awsome effort @andy666. Good to see you put the straps in, I saw years ago some one went down the same path with SurfPlan perhaps even the same arc plan and did not put in the straps or was it putting the strap on the wrong side, either way it developed a large dip in the profile. Good luck with the maiden flight.

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10 hours ago, Darren Tibbey said:

Be interesting how this compares to the Hi Archs. Seems to turn fast. Whats it pull like?

Yeah, it does turn pretty fast, but it's on a 50cm bar, so that's got a lot to do with it.

not sure how well it will go in the buggy yet. Very gusty wind.

when it gusted, guessing about 15knots, it had a bit of pull. But it's still way below its ideal wind range. Plus it may static fly well, but stall when up to speed in the buggy. Only time will tell.

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  • 3 months later...
  • 1 month later...
  • .Joel unfeatured this topic
  • 2 years later...

Hi All,

This is truly great work! Bravo!!!

So what is the verdict of this build after 3 years? Are there any updates to the plans or possible tweak suggestions?

How does the skin from the 16m2 host kite hold up in the 6m2 over time? That is almost a 3X wing loading increase (16m2 to 6m2)! Are there some extra reinforcements to perhaps consider in some areas?

I had found a file many years agi called the “buggy p-arc”  The .sle file I had found I had “Henry Kulk” (Holland?) as the author and it was also 6m2 (could it be of the same origin?).

My first build did not even fly because of the material (ripstop seconds). I had modded the design to make it more “Guerilla-ish” (wavy LE like in the PL patent) and bigger, 12m2. It that was quite successful I think, because it flew well. Unlike the F-Arc, it would relaunch better from the taco position as I recall because of the LE wave. Long time ago... gotta blow some dust off it that one. If it flies well I could post it.

I still have and old roll printer but I will try to laser cut this one. That way I can save on costly cartridges that keep drying out (Not again! 😞)

Thanks Olof for the de-wrinkle tip !!!

Paul

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@Paul Isabelle, no real updates. I flew the kite once in the buggy in about 20knots. It flew, but had a tendency to stall once the speed built. I fiddled with the front and rear strap a bit on the beach, which improved it a bit, but never fixed it. It would get up to a reasonable speed in the buggy and then simply stop accelerating.

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Thank you @andy666,

I also came across some other comments about this kite, the "p-arc". Some said to reverse the letters to know why and that spells cra-p to me ;-) Unless it was a tuning issue, I see no sense making one then. Has anyone got this thing to drive proper?

I will start by looking at the Surfplan file carefully. Maybe I can modify the kite parameters until I can get something that matches the F-ARC more closely. By printing key patterns such as the center and intermediate profiles, key panels, and basic overall dimensions of the end result, perhaps I can try to get a better match. My F-ARC1200 has no problems at speed as my kiteskiing sesh the other day reminded me, scary fast when that sucker winds up.

Has anyone ever sucessfully attempted to build one of the edgier arcs like the Hi-Arc? And what is it with those kites that make them so prime? It is more the overall layout that counts, or is it the airfoil profiles?

This brings up a much bigger question. How do we reverse engineer a kite?

  • Is there some way to scan it in 3D in flight under load?
    • Naw, I did not actually ask that... we will have stretching and billow to contend with...
    • Even inflated static, hung in the air free,... will not provide much
    • The accuracy of the scan would hose precision...
  • I guess there is little choice but...
    • Take one that flies well apart, panel by panel by panel
    • Trace or digitize each single panel, average left and right mirror panels for better accuracy
    • Try to recreate it in a 3D model using software like SurfPlan of Foilmaker
    • Bring all this into CAD via DXF and painstakingly compare... panels

Maybe one has to start over from scratch with the basic rules (Cp, AoA,coneing,...) and go through builds, tests, countless revisions...

Has anyone ever seen a Peter Lynn ARC design guide that lays out the rules?  If ever we figure this all out some day we should!

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FANTACTIC WORK ANDY !!!

Your kite appears to fly very well in the video that you posted. Bravo!

Have you ridden it at top speed yet (ie buggy or something)? How is it's power and depower? There is a lot to learn from your build.

I had built a 12m from the P-ARC design ten years ago or so, but it had many issues. Seeing your video has encouraged me to take that one out again. I am unable to get it airborne, but I think I know why now. The inflation vent valves are wrinkled from storage and do not shut well. I am fixing that and hope to be out testing it shortly.

But as I recall, at top speed, it would dive from the middle most violently. I had to always keep some brakeline pressure to avoid this. Has your kite done anything like that? If I can mine flying again, I will check that out proper.

Thanks Andy!

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