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Smaller lower aspect wing vs. bigger higher aspect

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tkaraszewski
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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby tkaraszewski » Tue May 26, 2020 6:46 pm

slowboat wrote:
Tue May 26, 2020 6:41 pm
Whattheflock wrote:
Tue May 26, 2020 6:13 pm
tkaraszewski wrote:
Tue May 26, 2020 3:34 pm

If you size a low aspect wing and a high aspect wing so that they have the same amount of lift at a particular speed, the high aspect wing will be smaller, and make less drag, thus allowing it to accelerate further. However at low speeds it will stall before the high aspect wing and it will require a larger turning radius (because if you turn it in too tight a circle, you will exceed the angle of attack at which it stalls).
A low aspect wing stalls before a high aspect wing at low speeds? Thought it was the other way around?

edit: sorry makes sense thinking about sailplane wings vs eg: fighter jets wings..

Why are foils like the 633 so popular for lightwind vs a higher aspect foil of a smaller area? More playful maybe?

Wouldnt a high aspect foil serve better?

I'm learning bare with me :wink:
It's the other way round. High aspect will stall before the low aspect as you slow down.
Slowboat is right, there was an error in my first post, I said the high aspect wing will stall before the high aspect wing, which is obviously wrong, since I used the high aspect wing in both places. :) The high aspect wing will stall before the low aspect wing. I edited my original post.

To maintain lift at low speeds, you need to increase the angle of attack of the wing. At some point, if you increase the angle of attack enough, water (or air, for airfoils) stops flowing smoothly over the wing and just turns into turbulence behind it. This is a stall, and the wing stops generating lift. A high aspect wing hits this point before a low aspect wing.

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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby TomW » Tue May 26, 2020 7:27 pm

Not trying to promote, but Gong now makes the M Pro with about 1000cm2, 23mm profile thickness. Its about 2 knots faster on average than the Moses 633 that has a 200cm2 more area and about same profile thickness and lower AR.( rode the 633 2 seasons). Interestingly, the low end is the same. The gong indeed has better vmg by a good margin.
Now gong released the Veloce series and the M size is 1000cm2 but even higher aspect and 13-14mm profile thickness if I Remember correctly.
So same area, higher AR and thinner profiles. They say its average 4 knots faster than Pro M, with slightly less low end, but better drive and glide through turns.
This is what I've been looking for. A big wing with faster characteristics. Ordered a set.
I rode the moses 590 one season too, but I found it too small in area at 633cm2
The moses 679 wing is 990cm2 and fairly high aspect. That might be good compromise too.

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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby purdyd » Tue May 26, 2020 7:46 pm

Comparing my cloud ix x24 and Armstrong HS1050.

The HS1050 is thinner, more area, and a higher aspect ratio.

The HS1050 is faster, and glides better and maybe a tad better in roll stability.

The x24 has a higher stall angle and can turn tighter.

The x24 is crazy easy to foil on and my preferred tool when things are challenging.

The HS1050 is a joy to use In normal conditions where you can enjoy the glide.
47D2F2A8-484A-4F8C-9FF7-0576F7456F29.jpeg
I’m looking forward to the new f series wings from cloud ix. The boys at cloud ix might have a great combination of glide and forgiveness,
56DA9C6B-224D-4730-B03A-DE409DA6761B.jpeg
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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby slowboat » Mon Jun 22, 2020 12:39 pm

tkaraszewski wrote:
Tue May 26, 2020 3:34 pm
Higher aspect wings are more efficient. They make more lift per a given amount of drag. This is why they are used on race foils, sailplanes, and the sails of racing yachts. But they fly at a lower range of angles of attack, which means they generally will not go as slow, nor will they tolerate mistakes as well.

If you size a low aspect wing and a high aspect wing so that they have the same amount of lift at a particular speed, the high aspect wing will be smaller, and make less drag, thus allowing it to accelerate further. However at low speeds it will stall before the low aspect wing and it will require a larger turning radius (because if you turn it in too tight a circle, you will exceed the angle of attack at which it stalls).
I wanted to revisit this because something is still not clear to me. Are we saying the lower aspect wing will be able to stay on foil at a lower speed than the high aspect wing (in the above scenario)?

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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby tkaraszewski » Mon Jun 22, 2020 4:02 pm

slowboat wrote:
Mon Jun 22, 2020 12:39 pm
tkaraszewski wrote:
Tue May 26, 2020 3:34 pm
Higher aspect wings are more efficient. They make more lift per a given amount of drag. This is why they are used on race foils, sailplanes, and the sails of racing yachts. But they fly at a lower range of angles of attack, which means they generally will not go as slow, nor will they tolerate mistakes as well.

If you size a low aspect wing and a high aspect wing so that they have the same amount of lift at a particular speed, the high aspect wing will be smaller, and make less drag, thus allowing it to accelerate further. However at low speeds it will stall before the low aspect wing and it will require a larger turning radius (because if you turn it in too tight a circle, you will exceed the angle of attack at which it stalls).
I wanted to revisit this because something is still not clear to me. Are we saying the lower aspect wing will be able to stay on foil at a lower speed than the high aspect wing (in the above scenario)?
Yes, the stall speed on a low aspect foil should be lower than the stall speed on a high aspect foil, all else being equal (i.e., both foils have the same total area). As you slow the foil down, you increase the foil's angle of attack. A foil with a longer path that the water travels over has more ability to smoothly redirect flow (i.e., prevent stalling) at high angles of attack. To illustrate, look at this graphic from the wikipedia page in "stall". You can see a wing flying at a very high angle of attack, but the flow over the top has stalled. Stretching the chord of the wing (i.e., making it longer from leading to trailing edge) will force more fluid to better follow the surface of the wing, resisting stall.

Here's the whole wikipedia article on stall.
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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby AndersP » Mon Jun 22, 2020 7:11 pm

I have found that the stab affects the perfomance of the foil much more than I thought before testing.

I used to kite with the Gong Rise and the 45cm kite stab.
I never felt the setup to be as slow as other said.
Then I tried the Rise with a surf 45 stab. It was soo stable and much slower than with the kite stab.

After that I tried the Curve/Gong pro M wiith the kite stab and it was really quick and reactive. A bit too much for me at that moment.

Then I tried the curve and 45 surf stab and everything went right. Quick and agile, easy to learn new maneuvers on. My favourite.

The kite stab has a very thin profile compared to the surf stab.

My conclusion is that if you want a fast setup with low stall speed, you should have a stab that has as low drag as possible, that you still can handle.

Next level for me is to try again with the Curve (pro M) and the 45 kite stab or even smaller.

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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby vol » Sun Jul 05, 2020 9:41 am

my favorite wing at this moment, very low ar
a bit lower slow speed but super stable pitch in the waves, actually because wingspan 47cm only it's so easy to turn, easy to jump
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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby jaros » Mon Jul 06, 2020 5:45 am

vol wrote:
Sun Jul 05, 2020 9:41 am
my favorite wing at this moment, very low ar
a bit lower slow speed but super stable pitch in the waves, actually because wingspan 47cm only it's so easy to turn, easy to jump
Interesting! Could you share some more details, dimensions, photos from side and bottom? Thanks!

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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby jaros » Mon Jul 06, 2020 5:45 am

vol wrote:
Sun Jul 05, 2020 9:41 am
my favorite wing at this moment, very low ar
a bit lower slow speed but super stable pitch in the waves, actually because wingspan 47cm only it's so easy to turn, easy to jump
Interesting! Could you share some more details, dimensions, photos from side and bottom? Thanks!

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Re: Smaller lower aspect wing vs. bigger higher aspect

Postby jaros » Mon Jul 06, 2020 5:45 am

vol wrote:
Sun Jul 05, 2020 9:41 am
my favorite wing at this moment, very low ar
a bit lower slow speed but super stable pitch in the waves, actually because wingspan 47cm only it's so easy to turn, easy to jump
Interesting! Could you share some more details, dimensions, photos from side and bottom? Thanks!


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