Switch Labs

[switchkites]

Good video! But you are saying that Best and Cabrinha are using the "industry standard" but that is wrong, Cabrinha for example is using this construction since 2008:

Hello Marc_87
If you open up the Cabrinha kites' leading edge, you will find Insigna cloth inside and not 175g Dacron. Cabrinha and other manufacturers, like Best and SS, decided to secure the Insigna cloth with a row of stitching. This will prevent the Insigna cloth from peeling and possibly getting stuck on the bladder.
All our tests were done using the 175g Dacron supplied by Dimension Polyant. We found this material to be the best suited for our leading edge and, if time allows it, we will film some tests with lighter weight materials used by the other manufacturers.
The sole purpose of this video is to demonstrate how different construction methods will yield considerably different breaking strengths.
Thank you for watching.
Your Switch Kites Team

[Marc_87]

As far as I know Cabrinha uses 165 gram Dacron for the LE and also the inside, also the way of stitching is more or les the same as your way.

But Naish and Slingshot sure uses the old fashion way of closing the LE seam.

[GregK]

Thanks for posting this video, I found it extremely interesting !! Anything to show us about canopy seam strength ?

How does the LE seam strength compare to the strength of the Dacron fabric ? If the Switch seam construction is 90% or more of the fabric strength, then you're there, no need for any further improvement - well done.

Which side of the seam failed, the fabric on the side opposite the fold ( what I call the flat side of this J-seam construction ) ?

Were any test made of a double-Dacron-layer J-seam without the outer webbing cover over the seam, as a double-layer J-seam is also a pretty common construction among many kite brands. This would show whether or how much the webbing contributes to seam strength.

Warning : it gets technical past this point, cool dudes hit the back button, techno-geeks read on ....

After 2.5 years in repairing kites full-time, I have not seen any LE seam failures caused by fraying of edges of the Dacron fabric. Which isn't to say it doesn't happen, just that i have yet to see it happen. I'm sure factories are using laser CNC cutters to form the LE fabric panels and this cutting process fuses the cut edge very well and limits fraying. LE seam failures that I have seen are either stitching failures or fabric tearing at the stitching holes. So IMO any strengthening of the seam from the webbing covering is a result of increased bend radius for the LE fabric as is wraps 90-degrees around the outer layer of webbing on the flat side of the j-seam. Because the webbing is typically loosely-woven and soft, again IMO it does not provide as much stress reduction on the fabric as would a much stiffer ( but harder to fold ) tightly-woven webbing.

Similarly, I believe putting the extra strip of Dacron on the outside of the LE fabric would maximize its utility, helping increase bend radius for the fibers in the main panel as they bend 90 degrees around the seam edge.

Would love to do a little design-of-experiment project on LE seam construction, but must away and fix some kites.

Huge KUDOS and props to Switch for doing real work to define and improve kite construction !!!

[switchkites]

Greg:
Seam vs fabric strength is indeed an important consideration. We have ongoing dacron, canopy fabric and associated seam tests however the video production is not finished. Your patience is appreciated.

Regarding the LE closing seam failure mode, it is weighted to the flat side but our Lab tests also show failures on the folded side.

As you mention, the webbing cover adds some strength by protecting the thread but LE seam strength is more a function of dacron (or other reinforcing) layers and their relative strength. You are also correct in noting the bend radius of the construction as a factor.

Attached is a pic which shows Switch LE construction and strut connection. The Dacron doubler is on the outside of the LE closing seam.
Thanks for your interest and questions.
Your Switch Kites Team

[GregK]

... the webbing cover adds some strength by protecting the thread but LE seam strength is more a function of dacron (or other reinforcing) layers and their relative strength.
Thanks for your interest and questions.
Your Switch Kites Team

Thanks guys !

So if the webbing isn't adding significantly to the seam strength and isn't needed to prevent edge ravelling, then here's my big reason not to use it - ease of repair. If your kite needs a LE repair, picking stitches out of that soft webbing is BRUTAL and adds significantly to the cost of a LE repair, where over half the work typically is dealing with the seam ( opening w/o damaging anything & closing up with same or better than original seam strength ). KISS is a great design guideline to follow.

Sure it make the LE seam look tough, but looking tough and being tough are two separate things.

Honestly though, top-notch recognition to Switch for building it right, based on solid mechanical design principles and backed up empirical lab testing for which the data is publically released, rather than just alluded to in a blurb of kite release promos.

[Kitego]

Any news on the fabric and seam construction testing? Is there going to be a video release soon of those test results?

Hello Kitego,
Sorry for the delay. Our video editing team has been busy with instructional and promotional videos.
Here is the first video covering the different leading edge seam constructions. More to come soon.
Enjoy!

I was looking for a replacement for my SS kite which after 20 outings ripped twice.I'm still a beginner and want the toughest kite available. Can't wait for the other video's but my mind is already made up, it will be a Switch Kite!

Thanks for being transparent about your work.

[switchkites]

Hello Greg:
We believe the webbing cover is beneficial outside ultimate LE Seam strength by protecting against abrasion and the thread cutting into the underlying dacron layers. Agree it adds labor to potential repairs but for the kite owner, fewer repairs are the Lab testing goal.

Hello Kitego:
Thank you!
Your Switch Kites Team

[naishdude]

Any news on the fabric and seam construction testing? Is there going to be a video release soon of those test results?

Hello Kitego,
Sorry for the delay. Our video editing team has been busy with instructional and promotional videos.
Here is the first video covering the different leading edge seam constructions. More to come soon.
Enjoy!

I was looking for a replacement for my SS kite which after 20 outings ripped twice.I'm still a beginner and want the toughest kite available. Can't wait for the other video's but my mind is already made up, it will be a Switch Kite!

Thanks for being transparent about your work.

YOU could have a look at the Switch Element or Nitro V3 both great kites also for beginners....
Element has less power , nitro has much more power all depending your skills and weight !
Method is also a pretty good freeride kite, but has the most barpressure of the 3, still the barpressure on the Method is nothing to be afraid off
have a look at the Switch forum...it will inform you from first hand experiences and advice !
good luck !
Cheers
dude

[consumer]

I'm becoming more interested into converting to an all switch kites quiver. However, out of simplicity I think i'll wait another season.

Do switch kites have split strut ? If not why not? My opinion is that it is not a gimmick and I like kites with it.

[switchkites]

Hello Consumer:
Thank You for your interest in Switch kites!

Split strut is not part of Switch kite construction. Using the kiteforum search feature will provide much feedback and opinions.
Thanks again!
Your Switch Kites Team