Contact   Imprint   Advertising   Guidelines

DIY onestrut kite

forum for kitesurfers


User avatar
tegirinenashi
Frequent Poster
Posts: 498
Joined: Wed Aug 27, 2014 3:29 am
Kiting since: 2003
Local Beach: 3rd Ave
Gear: Cabrinha CO2 9.5m, Naish x2 14m, Litewave 161
Brand Affiliation: None

Re: DIY onestrut kite

Postby tegirinenashi » Thu Nov 09, 2017 1:33 am

Bridle rendering seems odd. For the connection point to be in front of the LE there needs to be something that pulls it there. The four bridle connection points at the LE are behind it, I would suggest that the front line connection point is directly between them.

User avatar
PanTau
Medium Poster
Posts: 69
Joined: Mon Jan 23, 2012 9:42 am
Kiting since: 0
Gear: DIY kites and boards
Brand Affiliation: wingworks.de
Location: black forest
Contact:

Re: DIY onestrut kite

Postby PanTau » Thu Nov 09, 2017 1:45 pm

@
tegirinenashi wrote: Bridle rendering seems odd. For the connection point to be in front of the LE there needs to be something that pulls it there. The four bridle connection points at the LE are behind it, I would suggest that the front line connection point is directly between them.
I dont't understand your suggestion. This is how the bridle looks from the side. Working perfectly fine.

Image

kitexpert
Frequent Poster
Posts: 351
Joined: Sun Aug 09, 2015 11:20 pm
Kiting since: 2003
Gear: many kites, also diy
Brand Affiliation: None

Re: DIY onestrut kite

Postby kitexpert » Thu Nov 09, 2017 3:30 pm

Kites look good :thumb:

From the side view I don't see anything strange in the bridle and if and when it is working well it must be ok. Perspective on flyer views can be misleading sometimes if not always.

Couple of details which I wish I had in my design: 1) earlier mentioned angle bisector seams in LE 2) tapered strut ends. Also AR is a bit higher, but I don't have a problem with lower AR. Perhaps I taper strut ends manually, seams I just have to leave as they are.

User avatar
tegirinenashi
Frequent Poster
Posts: 498
Joined: Wed Aug 27, 2014 3:29 am
Kiting since: 2003
Local Beach: 3rd Ave
Gear: Cabrinha CO2 9.5m, Naish x2 14m, Litewave 161
Brand Affiliation: None

Re: DIY onestrut kite

Postby tegirinenashi » Thu Nov 09, 2017 5:17 pm

Force distribution should be balanced as viewed in any projection. However, even from the side view the angle split between forward and backward bridle must be equal if the tension is equal. As rendered above, the front bridle line goes almost straight to the control line implying that all tension is distributed to the front.

This is mostly theoretical gotcha anyways, because in practice the bridle will settle by itself so that the force balance is maintained. (I assume that slightly incorrect design would cause negligible effect upon the calculated bridle segments lengths).

Hansen Design
Very Frequent Poster
Posts: 602
Joined: Wed Feb 15, 2006 8:04 pm
Kiting since: 0
Brand Affiliation: None
Location: USA
Contact:

Re: DIY onestrut kite

Postby Hansen Design » Thu Nov 09, 2017 6:52 pm

Kites do not sit directly overhead due to drag. That means the towpoints are in front of the kite. Not directly below. CAD software can approximate the positions if the user arbitrarily predicts the drag angle, towpoint separation and bridle length. In practice, the towpoints move during sheeting and turning. If an active (pulley) bridle, the pulleys/sliders will travel to the low spots in their respective 'V' and the forces will resolve themselves. If a fixed or partially fixed passive bridle, the forces do not resolve themselves and the structure will see unequal forces. Subtle bridle 'tweaking' on either version can have dramatic effects and be considerably time consuming to optimize. Active pulley bridles generally are less problematic in this respect but are also less versatile in terms of tuning since the towpoints cannot be easily constrained. Mathematically, it is an indeterminate system with multiple solutions meaning a similar result can be had in a number of ways.

User avatar
PanTau
Medium Poster
Posts: 69
Joined: Mon Jan 23, 2012 9:42 am
Kiting since: 0
Gear: DIY kites and boards
Brand Affiliation: wingworks.de
Location: black forest
Contact:

Re: DIY onestrut kite

Postby PanTau » Thu Nov 09, 2017 7:56 pm

tegirinenashi wrote:
Thu Nov 09, 2017 5:17 pm
Force distribution should be balanced as viewed in any projection. However, even from the side view the angle split between forward and backward bridle must be equal if the tension is equal.
The tension is not spread equally between the bridle lines of the ventus. Highest tension is on the lines close to the center because this is where the lift is generated. But tension also changes depending on the amount of lift (and drag) the kite generates. So it makes sense to have the lines with highest tension more straight than the others. With a fixed bridle (no pulleys or sliders) you always have fixed angles but as Bill wrotes it's a lot of work to optimize the bridle settings. The bridle calculated by my software is only a starting point. The Kite is flying fine but you still have to fine tune the positions of the knots or even add some pulleys if you want.

Would be great if more of you guys would build kites and start to share your knowledge. I'm only a hobby kite builder living far away from the sea with little experience in kitesurfing.

Image

User avatar
kjorn
Very Frequent Poster
Posts: 623
Joined: Tue Feb 11, 2003 10:42 am
Kiting since: 0
Brand Affiliation: None
Location: uk
Contact:

Re: DIY onestrut kite

Postby kjorn » Thu Nov 09, 2017 8:05 pm

You should get the software to output the most simple sewing pattern and/or instructions. There must be an easier way to sew a kite together. Especially trying to get down to 1mm tolerances for the LE tube. It feels that sewing different bits of cloth together isn't as efficient as doing some sort of origami, folding then sewing then cutting off the excess cloth after sewing is complete.

kitexpert
Frequent Poster
Posts: 351
Joined: Sun Aug 09, 2015 11:20 pm
Kiting since: 2003
Gear: many kites, also diy
Brand Affiliation: None

Re: DIY onestrut kite

Postby kitexpert » Fri Nov 10, 2017 12:38 am

PanTau wrote:
Thu Nov 09, 2017 7:56 pm

Would be great if more of you guys would build kites and start to share your knowledge.
Absolutely. What I know is mostly about foil kites, so with LEI's guys like you PanTau have a leading role. And of course it is wonderful when there is some real professionals like Mr Hansen giving advice and explaining things. Although working with kites is quite rare hobby there is many other who have opinions/knowledge worth listening.

I like and appreciate your work because you have quite clear and physical approach to kite design and you give detailed specs from your kites to learn from. If I'll get some experience worth sharing from this one strut kite project I will do so, I just hope it will be more than don't do like this etc.. :)

kitexpert
Frequent Poster
Posts: 351
Joined: Sun Aug 09, 2015 11:20 pm
Kiting since: 2003
Gear: many kites, also diy
Brand Affiliation: None

Re: DIY onestrut kite

Postby kitexpert » Fri Nov 10, 2017 1:12 am

kjorn wrote:
Thu Nov 09, 2017 8:05 pm
You should get the software to output the most simple sewing pattern and/or instructions. There must be an easier way to sew a kite together. Especially trying to get down to 1mm tolerances for the LE tube. It feels that sewing different bits of cloth together isn't as efficient as doing some sort of origami, folding then sewing then cutting off the excess cloth after sewing is complete.
Unfortunately kites are not simple shaped things, so making one from flat pieces of fabric is not so straightforward. Of course some kite types are simpler than the other but if you are trying to do smooth kite which looks like modern kites usually look it is relatively difficult task. And not only shape is a concern but you must make kite strong enough for pressure and for some crashes.

You must also consider how final sewing is done to complete kite having closed and open parts. For sewing accuracy I don't think it is extremely precise as far as error is not cumulative. Fabric orientation must be thought also. Seams must be strong and tidy, so I don't see fabric cutting off after sewing possible.

User avatar
marlboroughman
Very Frequent Poster
Posts: 2687
Joined: Thu Feb 08, 2007 5:12 pm
Kiting since: 2005
Style: Oldschool
Gear: Switch
Brand Affiliation: Make Kiting Great Again!
Location: CubaKiteLessons.com
Contact:

Re: DIY onestrut kite

Postby marlboroughman » Fri Nov 10, 2017 1:47 am

I have no idea how to make DIY bridle but I had success implementing 06-07 Ozone five line set up which was basically working as a bridle on other open C kites. It is easy and it works, whereas you still get production kites with badly tuned bridles. If I had to make a bridle without knowing how the pros are doing it I would start tuning with five lines and try to visualize where to attach bridle points after, but why to go through all that trouble when it already flies perfect on 5.


Return to “Kitesurfing”

Who is online

Users browsing this forum: Bing [Bot], ChickenD!ken, Kehler, tj_boof and 33 guests

cron