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Does size matter?

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Peter_Frank
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Re: Does size matter?

Postby Peter_Frank » Thu Jan 25, 2024 8:18 pm

Windigo1 wrote:
Thu Jan 25, 2024 2:58 pm

Snip...

A foil with a short mast will be more stable because if you hit a turbulence in the water and the fuselage gets moved upwards 10 degrees this will translate in a smaller movement of the board with a short mast.

The board with a long mast will experience a larger movement for the same upward movement of the fuselage and the rider will experience a bigger movement on the board just like the less stable car. The rider will have to make a larger movement to bring back the foil to the neutral position with the long mast. Therefore from the rider point of view the board and foil are less stable with a long mast there is more movement and the absence of movement after a disturbance is defined as stability.

Snip....

I don't see this being correct.

Cant follow the reasoning, nor agree with this.

8) Peter
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Re: Does size matter?

Postby bragnouff » Thu Jan 25, 2024 8:42 pm

if your mast is not stiff enough, a longer mast will exacerbate this (even more so with large wings, and large riders), and you'll get more wobbles, or more flex which will introduce a bit more unpredictable behaviour in terms of response to your input. Shorter mast will be overall stiffer, with more direct response, hence appear more stable/solid.

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Re: Does size matter?

Postby Peter_Frank » Thu Jan 25, 2024 8:48 pm

bragnouff wrote:
Thu Jan 25, 2024 8:42 pm
if your mast is not stiff enough, a longer mast will exacerbate this (even more so with large wings, and large riders), and you'll get more wobbles, or more flex which will introduce a bit more unpredictable behaviour in terms of response to your input. Shorter mast will be overall stiffer, with more direct response, hence appear more stable/solid.

True - but it was not what was discussed - it was the horizontal lengthwise stability as I understand :D

It has to be a really bad soft mast though - if one can feel the difference, in particular for beginners :naughty:
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Re: Does size matter?

Postby leeuwen » Thu Jan 25, 2024 8:56 pm

Windigo1 wrote:
Thu Jan 25, 2024 2:58 pm
Stability is defined as “The propensity of an object to maintain it’s balance even after being disturbed in relation to the base of gravity. As a good example if a car has a low centre of gravity along with a wide base has been considered the most stable object”
You are right but you are also very wrong:
The main thing that disturbes the balance of a foil is not the turbulence in the water, the ride is buttery smooth after all, it is the RIDER.
And the impact of the rider weight movements is reduced with a longer mast.

So for all intents and purposing the rider riding the board will feel like a board that is more stable and eg you have more time to do footswitches.
MAYBE if you are in significant waves or whitewash a shorter mast will be less impacted but if you ride at similar length above the water the foil that is deeper (the longer mast) will generally have less impact from the waves AFAIK but I am not a huge wave rider.

Sure recovery from breaching with a short mast is easier because the angles and distances will be smaller.
And when you are in the “rodeo stage” of learning that’s probably a good thing but it is a dual edged sword:
Yes crashes are less gnarly BUT a short mast is more twitchy so it is harder to find the balance.

In regards to longer mast being wobbly because of flex; there is no reason a longer mast could not be stiff enough.
Get a better mast and/or lose some weight.
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Re: Does size matter?

Postby Trent hink » Thu Jan 25, 2024 10:41 pm

This might just be an argument over semantics...

Feedback is faster, and rider input is faster with a shorter mast.

Does that mean it is more stable, or less stable?

I hate the the convention of using the word "mast" when it comes to hydrofoils... Technically, it's a strut!

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Re: Does size matter?

Postby bragnouff » Fri Jan 26, 2024 1:42 am

leeuwen wrote:
Thu Jan 25, 2024 8:56 pm


In regards to longer mast being wobbly because of flex; there is no reason a longer mast could not be stiff enough.
Get a better mast and/or lose some weight.
There are several reasons, drag (thickness, profile), cost, weight. Always a matter of compromise.

The "enough" part of "stiff enough" is a fuzzy definition that evolves with whatever new wing design is released. Getting a better mast is not always possible once you're deeply invested in a foil ecosystem. Some of the masts were considered stiff enough, but turned out to not be stiff enough once longer spanned wings got introduced. (hence why Axis, Armstrong, Gong,... all released HM carbon masts to match that, and still recommend the shortest length for their biggest wings). And an extra 30cm of length makes a substantial difference at the end in terms of movement, flex and torsion, and eventually feeling, confidence in how much you can push the speed, etc...
As Peter pointed out, maybe this is not noticeable by beginners, but for an experienced foiler, it does make a difference. I'd say beginner wingfoilers use massive foil wings with sloppy off-axis foot positioning, and they are very likely to experience some of those flex consequences. It's just that they have bigger more urgent problems to solve with their technique before diving into the limits of the gear.


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