Found this interesting invention when researching Arcs. It's basicaly piece of fabric that the users sheet in and it moves into the arc shape pulling the users inward. The users then sheet out the kite and use there momentum to get back to the outside where they repeat the process.I don't know why they call it a kite if it doen't have lines though.

https://sites.google.com/site/iwworldswidestkite/

Interesting. Is it just me or does that guy seem to not know about the PL arcs? Also, while we're on the subject, is there really any reason for a twin skin, other than the obvious frame / rigidity / bernoulli foil considerations? I haven't actually looked at the Xsection of an arc, but I'd imagine there is *some* chord difference across the top/bottom skin for lift, eh?

If not, is there anything to stop a guy from just putting a few really thin, light struts across the middle of the kite to retain rigidity? Single Skin + 5 struts is probably slightly lighter than twinskin + 2 struts. Just thinking out loud .

Single skin is not as efficient as 2 skins. It is also harder to design a single skin kite. Spars or inflateable tubes are needed to support the fabric which add weight.
Foils use the differance in air presure to keep there shape. hybrids like foil nose 3 on 2e5.com use just enough or an air chamber to support the kite. I am still coming up with a design to make a hybrid arc prototype. I probably have +20 hours of research on airfoil shape and single skin gliders and kites. Not haveing a CAD program makes it even harder to design.

well that link is interesting in that it says copyright 2005 - what he has is exactly the same as many kite makers were making and flying at kite festivals going back to maybe early or mid 90s
I can't remember if we called them a ribbon arch or arch banner or something like that. Basically a long ribbon banner with a number of battens and a re-inforced leading edge and two sturdy handles/battens at each end. Two people would grab the ends and depending on the amount you tilt the ends and how close you walk together it produces an arch.

you may have seen long trains of small kites attached to a flying line one behind the other as they climb higher. In a similar way to the ribbon arch you can take a strong line and sew small kite skins (like diamond kites) to the string - you take the spreader rods out, stitch to the line and stitch a number side by side along the line. So instead of a train with kites one behind the other, they fly as an arch (side by side) when you stake one end of line and drag the other end across the wind and then staking it at a distance that gives the nice arch.

Proletariat, there are a number of single skin kites with battens; C-Quads and Paraski Flex to name a couple.
There are a lot of differences between open cell, closed cell and single skin. All have advantages and disadvantages. You can use a single skin on water but unless you have a floatation system on it, it will sink if falls in. A closed cell will float.
Now with ParaskiFlex, they do make an extremely high AR version only for team riders, I'll try and find a photo of one but here is one of their production models.

Quote:

Originally posted by Proletariat Interesting. If not, is there anything to stop a guy from just putting a few really thin, light struts across the middle of the kite to retain rigidity? Single Skin + 5 struts is probably slightly lighter than twinskin + 2 struts. Just thinking out loud .

Latest offering from Paraskiflex. Single skin, carbon leading edge, simple bridle, unique steering.
http://vimeo.com/57296711

High AR Paraskiflex...

http://www.microsofttranslator.com/BV.aspx?ref=IE8Activity&a...

The profile shape of the Arc's is not flat, it is actually curved outwards on the outside skin and then flared towards the trailing edge of the kite. This unique shape gives the Arc's it handling and flying characteristics. The inside skin also has a unique profile shape. This shape is made from the inside ribs of the kite. Without having some kind of structure or bridle network, you can't get the proper airfoil shape, thus the reason for either struts, bridles or twinskin designs.

Right, AWOC, that's what I meant when I said a Bernoulli foil profile. It was the only way I could think of for the arcs to turn (and float) as well as they do. More research on this topic when I fly my first Guerilla upon my return home

Snake, have you tried "DesignFoil"? I liked it a lot and built a bunch of prototypes that, it turns out, have already been made. I think it's expensive, but even the demo version is cool.



Also, Markite and Zero gee, am I the only one who finds those things terrifying? Aren't they just fully powered, single skin, c-hybrids with short lines flown on a big bar so you can manhandle the kite where you want it? I'd take an aggressive FB kite on handles over that any way of the week.

Originally, I was sort of thinking a single skin ARC with rigid supports, but as AWOC noted, the foil effect would go away, this making it a pretty lame kite. I would, however, like to see one of these paraskiflex attached to handles / bridle or a depower rig. They seem incredibly light. Perhaps that's a more realistic line of thinking. Assuming you don't care about it sinking, which we don't here in Colorado. Could make for some cheap kites.

Quote:

Originally posted by Proletariat Also, Markite and Zero gee, am I the only one who finds those things terrifying? Aren't they just fully powered, single skin, c-hybrids with short lines flown on a big bar so you can manhandle the kite where you want it? I'd take an aggressive FB kite on handles over that any way of the week. Originally, I was sort of thinking a single skin ARC with rigid supports, but as AWOC noted, the foil effect would go away, this making it a pretty lame kite. I would, however, like to see one of these paraskiflex attached to handles / bridle or a depower rig. They seem incredibly light. Perhaps that's a more realistic line of thinking. Assuming you don't care about it sinking, which we don't here in Colorado. Could make for some cheap kites.

The Paraskiflex are depower kites but they adjust the AoA like a windurfing sail. Sheet out with the back hand for less power, sheet in with the back hand for more power. Some models allow you to change the profile of the leading edge by zipping it in (not on the fly) for less power. You can also bring the wingtips together to change the projected area (not on the fly) of the kites for less power.

Steering the kite is very easy, just spin the bar. This method of steering is more intuitive (than push /pull steering) to a beginner and they pick it up and get going super quick.

One of the most amazing displays I saw that could change your mind about a paraski flex was at a winter festival at St Placide Quebec and they would take groups of at least 10 people at a time with no kite experience and after some explanation and demonstration had every single person out kite skiing in very short time - like 15 to 20 minutes. They had a bunch of kites laid out flat, just pick up the bar, turn it so the leading edge comes up and it goes, then the short lines and direct bar control make it simple to use and land and relaunch etc. With a number of kickers built on the lake, the team riders were boosting nice airs. There is a lot to be said for the design when you look out and within a few hours there are dozens and dozens of new riders having fun going all over the place and confident skiers already doing nice small jumps.