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DIY onestrut kite

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kitexpert
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DIY onestrut kite

Postby kitexpert » Sun Oct 15, 2017 10:39 pm

I decided to design a simple LEI kite. There is of course influence from Ultra, but it is not a copy by no means. I don't even know the specs of Ultra. Some details are not completed and I'm not publishing the bridle this time. Panel count is quite high as well as LE segments, because I don't like angular shapes. Also more seams in canopy give some strength and restrict stretching. And of course canopy follows more precisely airfoil shape when there is more panels.

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Hansen Design
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Re: DIY onestrut kite

Postby Hansen Design » Sun Oct 15, 2017 11:14 pm

Hello Kitexpert:
Looks cool!
I'm currently testing these for hydrofoil use. Both have either straight (luffable) or profiled user remove-able center struts and short fixed no pulley bridles. True 9sqm weight is 2Kg without strut, 2.5kg with.
Cheers!
Hansen-MSR-1a.jpg
Hansen-MSR-1a.jpg (68.39 KiB) Viewed 1236 times
Hansen-MSR-2a.jpg
Hansen-MSR-2a.jpg (63.4 KiB) Viewed 1236 times

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abel
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Re: DIY onestrut kite

Postby abel » Sun Oct 15, 2017 11:45 pm

If you're aiming at very light winds, keep in mind that every gram counts!
I observed that light wind kites use a huge wide and heavy inflating valve and single pump connector.
So following your simplicity concept, here are my 2c : Save the weight.
- use two old little valves, one for the leading edge and one for the strut. No connecting tube.
If anybody is too lazy for taking the effort of inflating two valves, then probably he will not bother riding in very light winds 8)
- consider sewing/sticking regular dyneema lines beneath the canopy along the the strongest tension areas and use the lightest cloth possible for the canopy.

Maybe aim at a target weight around 2.4 kg for a 12m2 (the Ultra is 2.8 kg), I trust that if you'll manage to reach the target, then it will stay in the air as much as foil kites do.

Good luck with the project :thumb:

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Re: DIY onestrut kite

Postby kitexpert » Sun Oct 15, 2017 11:59 pm

Hello Mr Hansen, and thanks for your kind words!

I see some similarity between our designs but like we've discussed earlier smooth LE is what we both like. Your method was different but using more angular segments is ok too and I guess the only possibility for me at the moment.

For relatively high panel count I have a practical reason too. I'm recycling some old PG's so I have to match my designs with cell widths of them. But I don't think it is much of a drawback at all.

One strut design or strutless is of course quite natural approach to low wind/hydrofoil use. No doubt there is some room for development there also, because kites of this segment haven't been so long around. Or did you design one quite a long time ago... :wink:

Your kites look smooth as always and idea for struts is interesting. MSR-1a has very wide wingtips though - just an observation.

I wish all the best for your tests :thumb:

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Re: DIY onestrut kite

Postby kitexpert » Mon Oct 16, 2017 12:11 am

Wise words, abel. To keep kite light weight is one goal for sure. Actually it saves quite a lot work too, to not have to make so much strenghtenings to kite. My project is anyway a prototype and I don't have so much experience of LEI design so it may be even a failure.

But I like challenges, and when you are not sure you most probably learn something new.

:thumb:

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Re: DIY onestrut kite

Postby downunder » Mon Oct 16, 2017 2:52 am

Congrats,

great work. Do you have a kite plan available? I think this might help with my project of converting an 2006 XBow to one/none strut kite. Should be easy, but, the angles are difficult to match with no plans.

D.

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Re: DIY onestrut kite

Postby BWD » Mon Oct 16, 2017 3:04 am

Having flown clouds a while, one piece of advice: copy a cloud.

They work great, very light --2.8 kg for 17m! Not 12m! 12m probably about 2.3!
They hold up well in spite of light build, I have one that is a c2 prototype (the designer used it to tune the bridle for the first c2 production) that had 100s of flights (on Maui) before I got it. Has a few stray threads here and there but still performs after years of heavy use.

I think the removeable monostrut idea is good, too. I'm interested to see what comes of it.
Last edited by BWD on Mon Oct 16, 2017 4:31 pm, edited 1 time in total.

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Re: DIY onestrut kite

Postby neptune262 » Mon Oct 16, 2017 6:18 am

abel wrote:
Sun Oct 15, 2017 11:45 pm
If you're aiming at very light winds, keep in mind that every gram counts!
I observed that light wind kites use a huge wide and heavy inflating valve and single pump connector.
So following your simplicity concept, here are my 2c : Save the weight.
- use two old little valves, one for the leading edge and one for the strut. No connecting tube.
If anybody is too lazy for taking the effort of inflating two valves, then probably he will not bother riding in very light winds 8)
- consider sewing/sticking regular dyneema lines beneath the canopy along the the strongest tension areas and use the lightest cloth possible for the canopy.

Maybe aim at a target weight around 2.4 kg for a 12m2 (the Ultra is 2.8 kg), I trust that if you'll manage to reach the target, then it will stay in the air as much as foil kites do.

Good luck with the project :thumb:
I can agree with this - the old system of one inflate and one deflate valve was a much lighter (weight) solution than the newer "high flow" plastic valves fitted as standard it seems. I have two struttless kites, one with the older two valves and one with the newer high flow valve - the two valve version has a better absolute low end for staying in the air IMHO. Not all upgrades end up being upgrades when it comes to light wind kites!!

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Re: DIY onestrut kite

Postby kitexpert » Mon Oct 16, 2017 11:02 am

Thanks guys for your interest :wink:

Fabric I have available is either Chikara or something perhaps bit lighter from PG's. Good quality stuff and I'm not seeking anything more light weight.

I have old valves available and one pump is of course not needed for one strut kite. Actually having separate valves gives an opportunity to have higher pressure in strut than in LE. Then strut can have a bit smaller diameter than usually for same stiffness making it a bit lighter.

I think I'll have that one strut and design more like Ultra or Mono than like Cloud to aim for a bit more universal kite. I haven't tested a Cloud however. I'm a bit worried about flutter even with one strut, because it is there in Ultras when looping... Clouds have smooth LE and quite high panel count which I like and will have in my kite.

Having some Airush style diagonal webbing is worth considering. I don't know if it have to be dyneema, actually it worries me a bit because diagonal cloth stretch and dyneema stretch are so different. But it seems to work.

-----

#downunder: I know your problem, actually I tried similar idea couple of years ago. I removed struts and cut LE to an angle to have wingtip shaped more than I liked and to get rid of heavy dacron. Unfortunately I didn't cut LE to correct angle so it became a weird at least and I also had difficulties to attach remaining canopy neatly to LE. That project is still unfinished and I will probably leave it as a kite for some spare parts and fabric.

I have of course plans available but I doubt if they are any useful for your project. Different size, different shapes etc. If you took some measurements from Crossbow and then design your own model it could help, but nor measuring neither designing to match is not quite simple task.

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Re: DIY onestrut kite

Postby Hansen Design » Mon Oct 16, 2017 4:23 pm

Understand the bladder(s) are a significant portion of the weight at about 115gm/sqm. Around 500gm on a 9sqm monostrut kite not including valves.


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