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Why a stabi, when wing foiling?

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fluidity
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Re: Why a stabi, when wing foiling?

Postby fluidity » Sun Dec 06, 2020 2:04 am

Here's the design I'm playing with at the moment.
At current design size:
Mesh volume is 5.8 litres.
Total surface area is 5581 sq cm so halving that we get around 2600 sq cm lift area after removing a bit for the mast socket, tips and curvy bits on the leading edges

It's a beast in volume but the dimensions of the box that contains it are only 800x450x50. It's a thick, fat wing. Narrow for low rotational inertia, thick to give almost 5 litres of under water flotation after subtracting CF/Glass cladding, long front to back to give an interim level of stability between high aspect unifoil and a full fuse, stab wing.

I took my first wing and split off a side, rotated to move the tip up so that I can fit a thick profile in a 50mm block of EPS foam and then mirrored it. This lets me fit more thickness in a block of foam as I don't need to worry about the wingtips moving curving way down into what would otherwise need to be a thicker block.

Because it's about 40mm thick at the centre and because it's low aspect ratio it doesn't need a lot of strength, just enough composite panels layered spreading from the mast foot to the close vicinity to take the biggest stresses.

Wouldn't it be nice to skip buying fuselage and stabiliser, and just buy a wing to fit straight under the mast??
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Re: Why a stabi, when wing foiling?

Postby Peter_Frank » Sun Dec 06, 2020 11:04 am

Yes, but the wing has to be forward of the mast, to give good dynamics and feel right.

Do you use an S profile, or rely solely on the rider for stabilization?

8) Peter

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Re: Why a stabi, when wing foiling?

Postby nemoz » Sun Dec 06, 2020 11:55 am

fluidity wrote:
Sun Dec 06, 2020 2:04 am
Here's the design I'm playing with at the moment.
At current design size:
Mesh volume is 5.8 litres.
Total surface area is 5581 sq cm so halving that we get around 2600 sq cm lift area after removing a bit for the mast socket, tips and curvy bits on the leading edges

It's a beast in volume but the dimensions of the box that contains it are only 800x450x50. It's a thick, fat wing. Narrow for low rotational inertia, thick to give almost 5 litres of under water flotation after subtracting CF/Glass cladding, long front to back to give an interim level of stability between high aspect unifoil and a full fuse, stab wing.

I took my first wing and split off a side, rotated to move the tip up so that I can fit a thick profile in a 50mm block of EPS foam and then mirrored it. This lets me fit more thickness in a block of foam as I don't need to worry about the wingtips moving curving way down into what would otherwise need to be a thicker block.

Because it's about 40mm thick at the centre and because it's low aspect ratio it doesn't need a lot of strength, just enough composite panels layered spreading from the mast foot to the close vicinity to take the biggest stresses.

Wouldn't it be nice to skip buying fuselage and stabiliser, and just buy a wing to fit straight under the mast??
Hi I think I'm probably the only one that never tried a foil with stabilizer, I started wingfoiling because during the first Covid Lockdown i had all the materials at home and a lot of time to design and build board, monofoil and Wing, I bought just the aluminium mast from Gong. I have no clue if a foil with stabi works better or not, but I like the one I built, I'm going to build a new foil soon and I will go a little bit smaller with higer AR and a different profile, my first one was 2600 and I'm only 63 kg, I will go for 2200 or 2000 with a different profile and AR to have higher top speed. I will ask to PrfctChaos to run a simulation to look to the correct profile.

I think you missed the real point, the point it is not skip buying fuselage, the real point is what is going to happen as soon as the manufacturers will find that they can sell you the monofil at the same price of the front foil, plus fuselage and stabi but with a fraction of the production cost? Well in my personal opinion it will came out that thanks to the Marketing manager and from Athlete that will claim monofoil is the future, best pumping, less drag and so on that no one can live without it.
Personally I would ask to PrfctChaos to run a simulation for your foil before proceeding in building it, just to have an idea.
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Re: Why a stabi, when wing foiling?

Postby geron » Sun Dec 06, 2020 1:52 pm

Peter_Frank wrote:
Sun Dec 06, 2020 11:04 am
Yes, but the wing has to be forward of the mast, to give good dynamics and feel right.

Do you use an S profile, or rely solely on the rider for stabilization?

8) Peter
I think peters recommendations are both the key: the mast further back makes the drag of this mast stabilize the wing, the rear area of the wing (that covers the mast, can be made so that it can be shimmed for more or less front foot pressure) I would make more of a round ufo type of overall oval shape.
The thickness of the wing does not have to be more than a regular one, in fact, it can be done by just adding a large flap (that contributes to the overall area) and a cut fuselage.

Geronimo

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Re: Why a stabi, when wing foiling?

Postby fluidity » Sun Dec 06, 2020 5:36 pm

nemoz wrote:
Sun Dec 06, 2020 11:55 am
I think you missed the real point, the point it is not skip buying fuselage, the real point is what is going to happen as soon as the manufacturers will find that they can sell you the monofil at the same price of the front foil, plus fuselage and stabi but with a fraction of the production cost? Well in my personal opinion it will came out that thanks to the Marketing manager and from Athlete that will claim monofoil is the future, best pumping, less drag and so on that no one can live without it.
Personally I would ask to PrfctChaos to run a simulation for your foil before proceeding in building it, just to have an idea.

You're right, I completely missed that point because i don't buy them, I make them myself! :D

And PrfctChaos is welcome to run sims on my foils but so far i haven't used NACA foils. I used maths, some examination of the foils that have good reports and fiddled with the numbers in my equasions until I got a foil profile I liked before he started that thread. I use OPENSCAD for my designs so it's all doe with programming on all my shapes.
It happens to be extroardinarily similar to one of the ones PfrctChaos found performs very well which is good enough for me for now. A useful simulation needs more than just the NACA profile though, thinned tips of shorter chord, my gull wing current head on profile, these all have real world implications that are only partially solved by a straight line simulation.

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Re: Why a stabi, when wing foiling?

Postby fluidity » Sun Dec 06, 2020 5:49 pm

geron wrote:
Sun Dec 06, 2020 1:52 pm
I think peters recommendations are both the key: the mast further back makes the drag of this mast stabilize the wing, the rear area of the wing (that covers the mast, can be made so that it can be shimmed for more or less front foot pressure) I would make more of a round ufo type of overall oval shape.
The thickness of the wing does not have to be more than a regular one, in fact, it can be done by just adding a large flap (that contributes to the overall area) and a cut fuselage.
Geronimo
I have contemplated a rounder shape and at some stage I'll go back to my openscad maths and do a brand new one. I think this shape is very suitable for a progression to unifoiling though.

I don't want to put the mast off the wing because it's deliberately a very low aspect wing, if you look at the Gong Alvator XXL front wing you'll see there is a cutout in the rear of the wing to allow the mast to rise up out of the fuselage and part of the back of the wing. It's slightly less area than mine and it's higher aspect ratio, wingspan of 1000mm instead of my 800mm. So all things being equal, my mast should sit forward of the rear of my wing with it's greater chord. However I can get that wing socket right at the back back and it's an easy change. :thumb:

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Re: Why a stabi, when wing foiling?

Postby geron » Sun Dec 06, 2020 9:13 pm

Fluidity, you wouldn’t want to make a wing like this for me (to fit my Moses masts) would you?
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Re: Why a stabi, when wing foiling?

Postby fluidity » Mon Dec 07, 2020 10:38 am

geron wrote:
Sun Dec 06, 2020 9:13 pm
Fluidity, you wouldn’t want to make a wing like this for me (to fit my Moses masts) would you?
Hi Geron,
I did some reading about thickness to chord ratio and apparently these long thick foil types generate a LOT of lift.
I did a new plan section with better resolution, gull-wing folded it again and made it a bit smaller than your dimensions. It's really a low speed unifoil. More pointy than yours(great for shedding seaweed)
Downloadable on here: If you can convince PrftChaos to run the numbers on it(I don't know if he is just going off NACA profiles or can run on an STL model file) then that might give you more use case possibilities information.

https://pinshape.com/items/103609-3d-pr ... ng-unifoil
Not quite your planned foot print and it's a bit narrower (600mm) due to the higher lift of the thick middle section. Only thick in comparison with other foils, because it's 450mm long it can have a low thickness to chord ratio and yet still be quite thick in the middle.
Graham.
Mesh volume:3.365 litres. Lifting area is around 1800 sq cm but keep in mind as above that the extra thick centre will make this more lifty than those 1800 sq cm would be for a high aspect foil and I think you'll get it at a low speed too.
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Re: Why a stabi, when wing foiling?

Postby Horst Sergio » Mon Dec 07, 2020 2:19 pm

geron wrote:
Sun Dec 06, 2020 1:52 pm
I would make more of a round ufo type of overall oval shape.
Sorry, don't agree.
To me monofoiling is all about low drag combined with moderate AR wings of 4-6 and so wing span which creates freestyle compatible compact setups without wings with high span and so low manouverability and pointy tips.
Going towards to low AR of 2 or lower means to increase induced drag significantly so loosing the main profit of a mono wing, then to me better keep the stabi. For the same reason I am not sure about significant S-shape profiles. As it seems human being is able to control also normal profiles with lower drag, it is maybe already good to use those normal profiles without to much S-shape.

Good example for monofoil ability is the dynamic lightwind 360s shown in the video. You need a low drag foil to accelerate in low wind and do a long wide 360 without slowing down. At the same time the wing span has to be moderate to incline relevant into the turn without having the tips surfacing or to not need a 125 cm strut. Additionally a foil is forgiving that is able to short cut the 360 on its end if needed. This all only comes together with a monofoil, why I have awesome fun to often do many 360s in a row, only problem actually is my just 90 strut which limits the accesible incline and so dynamic, next struts will be 96 or even 110 cm and wing just 63 cm span.

nemoz wrote:
Sun Dec 06, 2020 11:55 am
Hi I think I'm probably the only one that never tried a foil with stabilizer, I started wingfoiling because during the first Covid Lockdown i had all the materials at home and a lot of time to design and build board, monofoil and Wing, I bought just the aluminium mast from Gong. I have no clue if a foil with stabi works better or not, but I like the one I built, I'm going to build a new foil soon and I will go a little bit smaller with higer AR and a different profile, my first one was 2600 and I'm only 63 kg, I will go for 2200 or 2000 with a different profile and AR to have higher top speed. I will ask to PrfctChaos to run a simulation to look to the correct profile.
:thumb: don't waste your time with stabis :D . In fact, when a friend who wants to start winging and also rides monos since about 3 years asked me. I also said:
"Don't waste your time to use a stabi the first days, it is just needless."

With 63 kg I started with 2000 cm² wing fast skipped to 1500 cm² then ended winging as jumping was just no fun. Since having 1100 cm² I restarted and are getting more and more fun jumping, using the 1500 cm² rarely only for ultra light and surf, the 2000 cm² no more for winging. Actually waiting for the new board to install my fast 990 cm² Levitaz Cruizer wing with longer struts to see which jumping level I can achieve with this setup. :D

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Re: Why a stabi, when wing foiling?

Postby ronnie » Mon Dec 07, 2020 2:23 pm

Another way instead of a biplane, is to have 2 lifting wings which stabilise, but they do require a fuselage. For the XXLW model at 1300 sq cm total area, the largest of the 2 wings is only 56cm wide. It doesn't pump as well as modern surf wings.


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