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How thick is your wing?

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Peter_Frank
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How thick is your wing?

Postby Peter_Frank » Thu May 09, 2019 9:05 pm

Would not post on the thread about wing labelling wings, as off topic.

But some says that the "Surf/SUP" wings especially, are often really thick, but HOW thick?

Could some measure theirs so we get an idea of thickness?

Meaning, how thick is the wing 2-3 inch from the center, and what is the chord at this point?
This ratio will give you the wing thickness in percent.

Could be really interesting to know the range of thicknesses we experience.


Meassuring is quite easy if you are two, using two straight battens or a table edge and a cardboard edge or similar (apart from one or two rulers), requires a bit of patience to get it right :thumb:
Alone it can be difficult to measure the thickness though, holding everything with only two hands :roll:

My wings 500 to 1200 cm2 are all between 6.9 to 8.1 % thick, meaning very little range and most of them are between 7.5 and 8 %.

But have no idea about the other brands wings, what thicknesses we see :wink:

PS: jumptheshark, my Ketos 1200 cm2 wing IS actually their SUP wing and not a kite specific one, still only 8 % in thickness.

8) Peter

From the other thread:
Peter_Frank wrote:
Tue May 07, 2019 2:55 pm
jumptheshark wrote:
Tue May 07, 2019 2:35 pm
Snip...
A lot of the surf wings are pretty thick. They are currently the fashion and I think we will see kite wings settle on much thinner profiles but maintain decent overall area. Were still mid evolution and it takes a little research to figure out the different options out there.

Snip...

Are you sure about that?

I dont think so...
At least not for all brands - could be interesting if some would measure theirs (2-3 inches away from the center will give an idea).

The reason why many think they are "thick" is because they are wide.
It is not the thickness which is draggy, it is the thickness divided by the chord, meaning the thickness ratio.

I measured 4 or my Ketos wings, ranging from a fast small narrow 500 cm2 to a big wide Surf 1200 cm2 wing, and those between (in another thread).

And they were ALL roughly between 7 and 8 % in thickness, so the same :naughty:


So I dont think they are thick, eventhough I dont know the other ones apart from some being 10 %.

Having said that, I agree with you that there are so many different options that can work, maybe also work better :thumb:

8) PF

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Re: How thick is your wing?

Postby Jyoder » Thu May 09, 2019 10:28 pm

My DIY foil. I love it!

1100 cm2
9 inch chord in center
1 inch thick.

Sorry for mixing metric and standard.
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Re: How thick is your wing?

Postby Europ2 » Thu May 09, 2019 10:37 pm

Peter_Frank wrote:
Thu May 09, 2019 9:05 pm
But some says that the "Surf/SUP" wings especially, are often really thick, but HOW thick?
Could some measure theirs so we get an idea of thickness?

Meaning, how thick is the wing 2-3 inch from the center, and what is the chord at this point?
This ratio will give you the wing thickness in percent.
Ok, here are a few picts from GoFoil surfoil wings.... with 12-14%, a Supfoil airfoil section thickness to chord ratio (TCR or TR) is 50% higher than a kitefoil one
2017 wing: 12%
GoFoil airfoil section guesstimate.jpg
GoFoil airfoil section guesstimate.jpg (66.21 KiB) Viewed 422 times
2018 Maliko 160 wing: not measured but seems higher than 12%
201803 GoFoil Maliko 160 Airfoil S_1.png
201803 GoFoil Maliko 160 Airfoil S_1.png (371.05 KiB) Viewed 422 times
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Re: How thick is your wing?

Postby Kamikuza » Fri May 10, 2019 11:46 am

Very rough calculation, cos I couldn't get accurate read on the thickness...

820mm wide wing (SUP) was about 30mm thick and 235mm chord so t/C of about 13%.
AR 4.4 (span2/area)
Volume 2657cm2
Weight 1.1kg (bathroom scales FWIW)

https://cdn.shopify.com/s/files/1/0092/ ... grande.jpg

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Re: How thick is your wing?

Postby jumptheshark » Fri May 10, 2019 1:31 pm

will try to measure tonight, but can already tell my current big stingy wing will be lower end of the scale for %. It's the deepest chord of my wings so far but also much thinner profile than the stock and carver Zeeko wings.

In use, it can stay flying at incredibly slow speeds, cruises a little slower than the carver wing but can be pushed for good speed with little effort. It just doesn't stay at that speed, or more correctly if you choose to hold that speed, feels less stable/locked in. At first it felt slow, it definitely can idle along at pretty boring speeds, but you quickly learn it can be pushed. Feels like a dirt bike where you hit the gas for short hits of speed then lay off the throttle to corner and coast in terrain. Less thrilling in flat conditions, but super fun in small wind swell. Really look forward to getting it out in decent swell. Has lowered the starting point for my smaller kites by 2 knots and my ultimate low end with a 12m by a solid knot.

The stock Zeeko (530 cm) is pretty freeride oriented and quite fast all the time. Not race fast, but it needs a little speed just to fly. Accordingly it's also pretty quick to drop when the speed drops and you generally get pitched from the board coming down at 8-10 knots of speed. The carver is a really nice wing that still maintains a lot of effortless speed while cruising, yet can handle slowing down to 5 knots if your not to heavy on the board. I'm glad I have that wing and will definitely go back to it sometime. Have plans to try that one set up as a canard. The stringy wing is my favourite so far. Super carving with speed when you want it. Doesn't feel as locked in, so I tend not to maintain powered up straight lines for very long, but it accelerates really quickly when you power up the kite and glides well dissipating speed slowly while feeling really easy to control. Can drop down to nearly a standstill as long as you are pivoting in a turn and then just jet off in the desired direction. Falls from stall are just a drop straight down and you don't get pitched because you have barely any forward speed. Typically just dive the kite and your up again.

So far foiling is fantastic for its ability to change and adapt with a simple swap of the front wing. Like having completely different boards. Switching wings has been the most economical way to upgrade/change the ride. cheaper than a new kite or board by quite a long shot. Peter has been ahead of the curve on that and I'm starting to see what he's been talking about.

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Re: How thick is your wing?

Postby Kamikuza » Fri May 10, 2019 2:31 pm

jumptheshark wrote:
Fri May 10, 2019 1:31 pm
will try to measure tonight, but can already tell my current big stingy wing will be lower end of the scale for %. It's the deepest chord of my wings so far but also much thinner profile than the stock and carver Zeeko wings.

In use, it can stay flying at incredibly slow speeds, cruises a little slower than the carver wing but can be pushed for good speed with little effort. It just doesn't stay at that speed, or more correctly if you choose to hold that speed, feels less stable/locked in. At first it felt slow, it definitely can idle along at pretty boring speeds, but you quickly learn it can be pushed. Feels like a dirt bike where you hit the gas for short hits of speed then lay off the throttle to corner and coast in terrain. Less thrilling in flat conditions, but super fun in small wind swell. Really look forward to getting it out in decent swell. Has lowered the starting point for my smaller kites by 2 knots and my ultimate low end with a 12m by a solid knot.

The stock Zeeko (530 cm) is pretty freeride oriented and quite fast all the time. Not race fast, but it needs a little speed just to fly. Accordingly it's also pretty quick to drop when the speed drops and you generally get pitched from the board coming down at 8-10 knots of speed. The carver is a really nice wing that still maintains a lot of effortless speed while cruising, yet can handle slowing down to 5 knots if your not to heavy on the board. I'm glad I have that wing and will definitely go back to it sometime. Have plans to try that one set up as a canard. The stringy wing is my favourite so far. Super carving with speed when you want it. Doesn't feel as locked in, so I tend not to maintain powered up straight lines for very long, but it accelerates really quickly when you power up the kite and glides well dissipating speed slowly while feeling really easy to control. Can drop down to nearly a standstill as long as you are pivoting in a turn and then just jet off in the desired direction. Falls from stall are just a drop straight down and you don't get pitched because you have barely any forward speed. Typically just dive the kite and your up again.

So far foiling is fantastic for its ability to change and adapt with a simple swap of the front wing. Like having completely different boards. Switching wings has been the most economical way to upgrade/change the ride. cheaper than a new kite or board by quite a long shot. Peter has been ahead of the curve on that and I'm starting to see what he's been talking about.
I've had a brief look at the very scattered information and don't completely understand what I'm looking at, but it seems that thicker wings are better for high lift-needed applications in regards to stall speeds and stability. It seemed that for the range of speeds, t/C ratios and AoA we foilers are dealing with, the differences are practically negligible. One study even stated that 20% was the best t/C for low-speed (for aircraft) high-lift applications...

I'm pretty convinced it's more of an art than a science :D

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Re: How thick is your wing?

Postby jumptheshark » Fri May 10, 2019 2:59 pm

For foil wings, I suspect surface area is more important than profile thickness, where a big enough wing with low profile will get/keep you up at low speed, but glide with little resistance and allow for better speeds. There is of course a balance, where too much area will again be too much drag, but I suspect we don't require a lot of lift from the profile per se. Might be different if your lifting a whole SUP or windsurfing rig, but for our needs where some rider weight is already often decreased by the kite, profile is probably not the biggest concern.

Could be way off base,

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Re: How thick is your wing?

Postby jumptheshark » Fri May 10, 2019 4:46 pm

Just measured the big stringy wing and its chord is 24 cm and max thickness just under 1 cm so no more than 4%
IMG_4067.jpg
IMG_4065.jpg

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Re: How thick is your wing?

Postby Peter_Frank » Fri May 10, 2019 5:14 pm

Thanks for measuring guys :thumb:


Amazing, the Maliko 160 is 17 % thick.

And the Stringy is 4 % thick and low almost no camber.

Understandable we got so different views on how thick the big wings really are, we see EVERYTHING :naughty:


Camber is the most important factor regarding lift, not thickness eventhough part of it.

But a high camber wing has loads of drag when going fast (low AOA).
So thin high camber wings does not make much sense.

A thick wing has more drag "always", but the advantage is the range is better, meaning it can ride both slow or fast without huge drag, just its "normal" somewhat higher drag.

A thin wing with low camber got low drag at high speed, but at low speed it doesnt work well - thus more area is needed, again giving more drag.

The best compromise between camber/thickness/area can be combined in endless ways that all work, but they dont work the same :rollgrin:

8) Peter

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Re: How thick is your wing?

Postby jumptheshark » Fri May 10, 2019 5:30 pm

Peter_Frank wrote:
Fri May 10, 2019 5:14 pm
Thanks for measuring guys :thumb:


Amazing, the Maliko 160 is 17 % thick.

And the Stringy is 4 % thick and low almost no camber.

Understandable we got so different views on how thick the big wings really are, we see EVERYTHING :naughty:


Camber is the most important factor regarding lift, not thickness eventhough part of it.

But a high camber wing has loads of drag when going fast (low AOA).
So thin high camber wings does not make much sense.

A thick wing has more drag "always", but the advantage is the range is better, meaning it can ride both slow or fast without huge drag, just its "normal" somewhat higher drag.

A thin wing with low camber got low drag at high speed, but at low speed it doesnt work well - thus more area is needed, again giving more drag.

The best compromise between camber/thickness/area can be combined in endless ways that all work, but they dont work the same :rollgrin:

8) Peter
Bolded and underlined one part there. How do you mean doesn't work well? In your opinion, what aspect of that stringy wing will not be as good? (not being sensitive here, more trying to understand) So far as I can tell, it has a ridiculously low stall speed. Water is dense and that surface area enough to keep you flying at walking pace without issue beyond boredom. The only downside I can think of would be more sudden onset of stall but from real world feel, your going soooo slow, you expect the drop out when it happens. Lately have been drift launching a lot and at the end have to coast in toward shore through a wind shadow. No kite power, slowly bleeding speed with intent to drop before it gets too shallow and ideally put the kite down on land. The wing always carries me farther than I think it will and I usually have to hop off intentionally before is slows enough to stall. Effectively, the stall speed is so low, it doesn't really matter that it might be more sudden than a wing with more camber.


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