Contact   Imprint   Advertising   Guidelines

Building a state-of-the-art foil kite

For all foil kite riders
foilholio
Very Frequent Poster
Posts: 2620
Joined: Sun Aug 23, 2015 3:20 am
Kiting since: 1337
Local Beach: Ventura Beach
Favorite Beaches: Tarifa
Style: Airstyle
Gear: Foils
Brand Affiliation: None
Has thanked: 88 times
Been thanked: 25 times

Re: Building a state-of-the-art foil kite

Postby foilholio » Sun May 05, 2019 1:22 am

kitexpert wrote: Because main objective would be to decrease drag by trying to make very clean wing I see now 3 line row bridle not so suitable.
My point is the reduction in drag from less bridles with 3 rows may be better than the cleanness with 4 rows.
kitexpert wrote: I'm not sure if I got it right but you have experimented some sliding system between cascaded B-C? This should help it to adjust when AoA changes but it makes bridle a bit more complex and and adds wearing lines to it. Perhaps with some small steel rings as a pulleys it could be done neatly/lightly enough and range of movement perhaps limited (after which B-C would be fixed). Possibly then 1:2 speed system would suit better to 4 line rows.
You have it right except I used a pulley between B and C. It really didn't work at all. Lost camber control and the kite had a dynamic way of adjusting between B and C. I did use a 1:2 mixer. Maybe 1:3 could have improved things.

User avatar
downunder
Very Frequent Poster
Posts: 1761
Joined: Mon Jul 01, 2013 7:16 am
Kiting since: 1970
Gear: building my own
Brand Affiliation: None
Location: Perth, Australia
Has thanked: 9 times
Been thanked: 19 times

Re: Building a state-of-the-art foil kite

Postby downunder » Sun May 05, 2019 4:59 am

As mentioned,

It's extremely difficult to find resources for building even LEI kites.

As opposed to huge resources for boards building, DIY kits easily accessible, materials etc. We have spent years in providing hands on knowledge.

However, I think it is noticeable that people do not make diy boards any more as they used to. The peak was about 4 years ago. Not sure why tho, used market maybe, who knows.

Stefano built the CNC cutting machine, so the aim was to build more kites not only for himself.

kitexpert
Very Frequent Poster
Posts: 743
Joined: Sun Aug 09, 2015 11:20 pm
Kiting since: 2003
Gear: many kites, also diy
Brand Affiliation: None
Has thanked: 1 time
Been thanked: 6 times

Re: Building a state-of-the-art foil kite

Postby kitexpert » Sun May 05, 2019 8:09 pm

Regis-de-giens wrote:
Sat May 04, 2019 10:19 pm
We are asking this to Kiteexpert for month, and unfortunatelly we have nothing real now, that is regrettable.

Of-course a mid AR kite cannot reach the same level of LD ratio than high AR kites. Otherwise all designers from all brands around the world and among years would be idiot developpers ? And even assuming this point ... then the same super-ideal kite would have an even better LD ratio and race performances with a bit higher AR (induced drag would mathematically be reduced, hence better in race..) Come-on ...


Foilholio is naturally right, there are different kites for different use, and some design feature like arch of the profile have to be increased or decreased depending on speed or wave wish for example.

Big respect for Stephano Moris for its impressive work and hope that people will continue do diy kites.
We don't exactly know how high L/D ratios could be possible for mid AR kites, I mean by not increasing L but decreasing D. Some high end PG's however can make a crossover to next class in performance. Like I wrote foil kites are far from being clean wings, actually they are quite bad.

:) No, designers have not been idiots, they have had to design kites which are good enough end cheap enough to produce. This topic is not about those kind of kites but high end kites. I'm afraid many designers would not have been up to that kind of work by judging what kind of kites they have designed and produce at the moment.

Apparently you mean airfoil camber with the "arch of the profile" - yes to have appropriately chosen/designed airfoil (camber, stability) is one of the most important factors in (foil) kite design. Canopy curve (how flat or C-shaped kite is) is another but not as critical choice.

I'm sorry I'm not able to publish any pics or vids. I am not sure if I should publish even designs because they contain quite a lot that information I've collected with hard work during last 15 years. For some enthusiastic builder I perhaps could offer patterns, and I can also give help or do redesigns for bridles of existing kites which quite often would need it. It is also ok for me that some commercial kite manufacturers use my suggestions which I have published here, they have to do it anyway sooner or later.

kitexpert
Very Frequent Poster
Posts: 743
Joined: Sun Aug 09, 2015 11:20 pm
Kiting since: 2003
Gear: many kites, also diy
Brand Affiliation: None
Has thanked: 1 time
Been thanked: 6 times

Re: Building a state-of-the-art foil kite

Postby kitexpert » Sun May 05, 2019 8:20 pm

foilholio wrote:
Sun May 05, 2019 1:22 am

My point is the reduction in drag from less bridles with 3 rows may be better than the cleanness with 4 rows.
In my current mind set I'd try to do everything which is possible (within some reason) to reduce drag. Higher cell count means however more bridle line so there is a challenge for design and especially for well designed bridle. I have ideas how to do it and also how to do it with relatively light weight.
foilholio wrote:
Sun May 05, 2019 1:22 am
You have it right except I used a pulley between B and C. It really didn't work at all. Lost camber control and the kite had a dynamic way of adjusting between B and C. I did use a 1:2 mixer. Maybe 1:3 could have improved things.
Ok, that actually sounds right because it is not very likely floating system would necessary do anything good, that is why I thought some limiting for the movement. 1:3 would very likely to improve difficulties but it doesn't change AoA as much as normal ratios do, so in that sense it is less efficient.

sms-kite
Rare Poster
Posts: 31
Joined: Thu Jun 03, 2010 5:35 pm
Kiting since: 15
Local Beach: Montpellier
Favorite Beaches: Le semnoz for snowkiting
Style: a l'arrache
Gear: Sup'air Takoon
Brand Affiliation: a lot
Location: Chambery-France
Has thanked: 0
Been thanked: 0
Contact:

Re: Building a state-of-the-art foil kite

Postby sms-kite » Mon May 06, 2019 4:44 pm

Hello,

Just my 2cents

1-Paraglider have nothing to compare with a kite. It is really not the same, really nothing to compare. It was different in the past and now there is really nothing to compare between a kite and a paraglider. So the art of conception for a paraglider is totally out of date for a kite. So to me, there is no interest to copy a paraglider.

2-Have a better L/D ratio is not the "goal" in kitesurfing (not mine). The goal is pleasure, seccurity, so easy to ride, good satbility easy to understand and to relaunch... On the most of the freerace kite, the L/D is not a point of conception. And it is the same in tube kite... Performace is the best way to kill the fun.
So may be, kite designer prefer an happy customer, than sold kite abble to pass the 45kts on the water. The most of the customers are using kite at 50% of the performances. So if you want more perforamnce, push it first... This is my global spirit, not only a buisness model


3-Make a foil kite is long. It is difficult to design, difficult to assemble, difficult to trim. So eaven if you have a drawing, it is quite difficult to do it. Tube kite or board are more easy to built. So you will see more boards, less hydrofoils, more tubes kites, less foilkites.

4-Design and built kite it's a job, a lot of things to know. If you want to do it, you can do it by yourself because you don't need specific material. So nothing really expensive to begin. What it is sure is that the first kite will be a really good feeling for you (even if the kite is really not good). I build a lot of kites and some paraglider, the first trying is a great moment.
But never do this to win money, because you will lost a lot...

BR

Nono

kitexpert
Very Frequent Poster
Posts: 743
Joined: Sun Aug 09, 2015 11:20 pm
Kiting since: 2003
Gear: many kites, also diy
Brand Affiliation: None
Has thanked: 1 time
Been thanked: 6 times

Re: Building a state-of-the-art foil kite

Postby kitexpert » Mon May 06, 2019 5:46 pm

sms-kite wrote: Hello,

Just my 2cents

1-Paraglider have nothing to compare with a kite. It is really not the same, really nothing to compare. It was different in the past and now there is really nothing to compare between a kite and a paraglider. So the art of conception for a paraglider is totally out of date for a kite. So to me, there is no interest to copy a paraglider.

2-Have a better L/D ratio is not the "goal" in kitesurfing (not mine). The goal is pleasure, seccurity, so easy to ride, good satbility easy to understand and to relaunch... On the most of the freerace kite, the L/D is not a point of conception. And it is the same in tube kite... Performace is the best way to kill the fun.
So may be, kite designer prefer an happy customer, than sold kite abble to pass the 45kts on the water. The most of the customers are using kite at 50% of the performances. So if you want more perforamnce, push it first... This is my global spirit, not only a buisness model


3-Make a foil kite is long. It is difficult to design, difficult to assemble, difficult to trim. So eaven if you have a drawing, it is quite difficult to do it. Tube kite or board are more easy to built. So you will see more boards, less hydrofoils, more tubes kites, less foilkites.

4-Design and built kite it's a job, a lot of things to know. If you want to do it, you can do it by yourself because you don't need specific material. So nothing really expensive to begin. What it is sure is that the first kite will be a really good feeling for you (even if the kite is really not good). I build a lot of kites and some paraglider, the first trying is a great moment.
But never do this to win money, because you will lost a lot...

BR

Nono
Well, kites have been slowly developed to higher performance and foil kites have used exactly same methods as PG's have: higher AR, higher cell count, lower drag bridle, LE stiffeners, diagonal ribs, inner straps etc. etc. There is no difference because structurally both foil kites and PG's are same. FS Soul is the technical leader at the moment in foil kites (excl. race kites) and it is very much a kite which fits under this topic. But to copy a Soul or to copy any kite is not very interesting so I am designing or aiming one step higher.

My intention has never been to try to copy or convert PG to a some kind of a kite, because there is known differences between the two.

It is true if kite builder does not have some experience fabricating a kite from the drawings (patterns) is a suspicious try. At least kite should be easy, like some Ozone Access/CA Wave type simple kite. Everything is easier with that kind of kite.

I have a lot more pleasure with a high performance kite like Soul or even some race kite than with a low performance kite which is soft and slow and boosts poorly. Actually I don't have any use for that kind of kite. Some like them, I don't. From design perspective I don't see much interest in them either, even though I have designed most usable cell counts and bridle configurations for low AR foil kites.

sms-kite
Rare Poster
Posts: 31
Joined: Thu Jun 03, 2010 5:35 pm
Kiting since: 15
Local Beach: Montpellier
Favorite Beaches: Le semnoz for snowkiting
Style: a l'arrache
Gear: Sup'air Takoon
Brand Affiliation: a lot
Location: Chambery-France
Has thanked: 0
Been thanked: 0
Contact:

Re: Building a state-of-the-art foil kite

Postby sms-kite » Tue May 07, 2019 9:50 am

kitexpert wrote:
Mon May 06, 2019 5:46 pm


Well, kites have been slowly developed to higher performance and foil kites have used exactly same methods as PG's have: higher AR, higher cell count, lower drag bridle, LE stiffeners, diagonal ribs, inner straps etc. etc. There is no difference because structurally both foil kites and PG's are same. FS Soul is the technical leader at the moment in foil kites (excl. race kites) and it is very much a kite which fits under this topic. But to copy a Soul or to copy any kite is not very interesting so I am designing or aiming one step higher.

My intention has never been to try to copy or convert PG to a some kind of a kite, because there is known differences between the two.

It is true if kite builder does not have some experience fabricating a kite from the drawings (patterns) is a suspicious try. At least kite should be easy, like some Ozone Access/CA Wave type simple kite. Everything is easier with that kind of kite.

I have a lot more pleasure with a high performance kite like Soul or even some race kite than with a low performance kite which is soft and slow and boosts poorly. Actually I don't have any use for that kind of kite. Some like them, I don't. From design perspective I don't see much interest in them either, even though I have designed most usable cell counts and bridle configurations for low AR foil kites.
May be you right, may be not...
The AR ratio is lower than a speed
Speed 5 12 sm ratio 6.15 cells 41
Soul 12sm ratio 5.55 cells 41
So ratio decrease, cell number equal... Looks like is the performance don't come from paraglider technics.

And to me the Soul as the Speed is really not a hi performance kite. And it's seam to be the same feeling for Flysurfer because they have the VMG and the Sonic... So in fact it is a middle-low performance kite if you are speaking about the L/D ratio in the Flysurfer products range. A lot of guys coming from the kitefoil are thinking the same as I.
What I can tell you is that the profil is not a performance profil too.

So the best kite looks like:
-middle ratio
-41 cells
-stability profil

The best seam to be the less performance no?

Best regards

Nono

kitexpert
Very Frequent Poster
Posts: 743
Joined: Sun Aug 09, 2015 11:20 pm
Kiting since: 2003
Gear: many kites, also diy
Brand Affiliation: None
Has thanked: 1 time
Been thanked: 6 times

Re: Building a state-of-the-art foil kite

Postby kitexpert » Tue May 07, 2019 10:33 am

Yes of course race kites are the highest performance kites but they have their known issues, they are quite difficult kites.

So I'm not interested in to challenge race kites. We have already seen a 13m kite with 13m wingspan and AR 13. It was a curiosity, showed the limits and obviously passed them. Should I try AR 15? :) no. Normal race kites are also so finished products there is not much work to do in them.

To say Soul is a middle-low performance kite is a bit too much when it easily beats all LEI's and all other foil kites not including race kites by its L/D. But I'm not saying everyone should buy a Soul because there are many other things than L/D which are essential in kites.

Soul is the best foil kite in general at the moment. With Soul it is possible to megaloop, jump over 28m high and have 17s hang time from the flat surface. No other kite has anything comparable. That shows mid AR foil kite concept has huge potential.

sms-kite
Rare Poster
Posts: 31
Joined: Thu Jun 03, 2010 5:35 pm
Kiting since: 15
Local Beach: Montpellier
Favorite Beaches: Le semnoz for snowkiting
Style: a l'arrache
Gear: Sup'air Takoon
Brand Affiliation: a lot
Location: Chambery-France
Has thanked: 0
Been thanked: 0
Contact:

Re: Building a state-of-the-art foil kite

Postby sms-kite » Tue May 07, 2019 3:07 pm

kitexpert wrote:
Tue May 07, 2019 10:33 am

To say Soul is a middle-low performance kite is a bit too much when it easily beats all LEI's and all other foil kites not including race kites by its L/D. But I'm not saying everyone should buy a Soul because there are many other things than L/D which are essential in kites.

Soul is the best foil kite in general at the moment. With Soul it is possible to megaloop, jump over 28m high and have 17s hang time from the flat surface. No other kite has anything comparable. That shows mid AR foil kite concept has huge potential.
Sorry, but I am not really agreed with your point of view...

Soul beats easely a tube kite? Even if you are looking to do Kiteloop? Are you sure? Do you ever trie to make a big kiteloop in gusty wind with the Soul??? Because I do kiteloop with a TT since 12years with an hybride kite... I do it on the snow with foil kite and I really don't want to test a 10sm foilkite in 20kts in kitesurfing.
It is not because some top riders do this, this year, that it is a revolution... Top riders done megaloop with tube kite since 2002-2003... So the Soul have the same performance than a 2003 kite?

Foil kites are really not at the same level on depower and turn ability... They have good points and they have bad points like tube kites, like everything. The soul doesn't change the problems, today everybody can do a kite loop with a tube kite, it is so simple... And make a kiteloop with a foil kites needs to be on the good timing in the good wind with a good rider.

I change between tube kite and foil all over the year... I am always surprise when everybody tells me "The soul turns as a tube kite, the soul have the same depower"...I test it, nothing to compare. Or I heard "my tubekite is lighter than a foil, my tubekite have the same power..." seriousely a tube kite have 10-15% less power for the same surface and it is 800-1000gr heavier.

I understand that you love your soul, but this kite is more a freeride kite than a top performant kite. It is a well balance kite. But his L/D ratio is not incredible. It is approximatively the same than a race tube kite... But nobody have race kite to compare anymore.

I think that the freeride foil kite is the more interested kite because it's closed to the rider level and with the way that riders want to kite. But clearely, on every brand the L/D ratio decrease on the most popular foil kite. And it is not a design problems, it is because they want to go for a well balance kite, easy to run, fun and seccurity...

Best regards

Norbert

kitexpert
Very Frequent Poster
Posts: 743
Joined: Sun Aug 09, 2015 11:20 pm
Kiting since: 2003
Gear: many kites, also diy
Brand Affiliation: None
Has thanked: 1 time
Been thanked: 6 times

Re: Building a state-of-the-art foil kite

Postby kitexpert » Tue May 07, 2019 3:53 pm

I agree most of your post, and I use more tube kites than foils nowadays. But I've worked since the beginning with foil kites and I know them best. I am not at all fundamentalist for neither kite type or any kite type and I wouldn't suffer to back to foils because latest mid AR kites (and some race kites also) are so good. But I don't have a reason to do it.

For Soul I meant combination of what is achieved with it, but of course same size of Soul will not megaloop and have 17s hang time :) I doubt if any race tube kite can keep up with the Soul for example upwind, because it has about same performance as old Speeds had or even better. And after all race tube kite is in practice a non-existing kite type today, I don't know if there is any in production.

I don't know what negative would be to have mid AR foil kite usability combined with higher performance. Only question I see is how to do it. IMO it can be done only by making it better, having cleaner wing with low drag bridle.


Return to “Foil Kites”

Who is online

Users browsing this forum: No registered users and 2 guests

cron