KT Foils low end

Is there already a post on here about this? Wondering if any have feedback on the NEW KT foil range touted at AWSI 24 as having built in low end (kind of 'stall flaps') and as such better range. Sounds like a dream that could be coming true.

Won,t be available before feb in Europe says my shop (they ordered a LOT of them).

Is this what they call 'groove' in foiling

From plantpositivefilms a few days ago. Stall speed with 3 different Atlas front wings.

Kestrel, that's really neat, and very informative, stall speed and then how the foil 'let's go' when it hits that stall point, some foils bring the board down like a landing others just give up and you drop with a little bump.

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jondrums said..
I'm a social media idiot - how are you seeing this video by plantpositivefilms? I can't even find a still image that you shared on their social accounts

+1 ... and I follow Gwen through a few channels

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sunsetsailboards said..
I rode the 790 Atlas... stall speed was really low... low end was about what I would expect out of a foil that size

My lack of understanding here - I assumed a lower stall speed meant more lift at low speeds so easier to get flying (a better low end). Or are they different?

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hilly said..
At the cost of top end. Would be awesome in small waves but any decent swell might be a challenge.

I can't speak specifically to the KT foils, having not tried them, but this statement is not always true and low end vs high end (speed and power) isn't a zero sum game. Speed range is highly variable between foils and a broad speed range is one of the most important variables I look for in a foil. How the foil behaves at the top of its speed band is also a major factor. Some foils get pitchy at the top end of their speed band, while others just ramp front foot pressure.

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Velocicraptor said..

hilly said..
At the cost of top end. Would be awesome in small waves but any decent swell might be a challenge.

I can't speak specifically to the KT foils, having not tried them, but this statement is not always true and low end vs high end (speed and power) isn't a zero sum game. Speed range is highly variable between foils and a broad speed range is one of the most important variables I look for in a foil. How the foil behaves at the top of its speed band is also a major factor. Some foils get pitchy at the top end of their speed band, while others just ramp front foot pressure.

One of the characteristics that comes into play is the lift-to-drag ratio. If you have two foils with the same take off (or stall) speed, then the foil with the better lift-to-drag ratio can theoretically go faster. That assumes that the total forward (hand wing) power is limited, either by the amount of wind, or by how much power the winger can handle.

Lift-to-drag is just one factor, and perhaps not always the most important one for speed range. Perhaps it's main advantage is that you can get L/D curves out of fluid dynamics simulations. On the water, how a foil behaves at the top end speed can be the more relevant factor. You can get some clues from simulations - a foil that has a L/D curve with a narrow maximum and a rapid decrease after the max will likely be more pitchy than on with a wider curve that falls off more slowly. But that behavior depends on other system components, too, so it's not as easy to simulate.

Do we think this wider speed range is coming from the camber, or the reflex on these new foils. I remember back in my slalom windsurfing days when reflex started to appear on fins, this gave a lot more control at high speeds in rough water.