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.
Haven't had a chance to ride yet, but there are heaps of videos that everybody has likely watched already.
Won,t be available before feb in Europe says my shop (they ordered a LOT of them).
From plantpositivefilms a few days ago. Stall speed with 3 different Atlas front wings.
I rode the 790 Atlas... stall speed was really low... low end was about what I would expect out of a foil that size
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.
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
Select to expand quotejondrums 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
Select to expand quotesunsetsailboards 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?
At the cost of top end. Would be awesome in small waves but any decent swell might be a challenge.
Select to expand quotehilly 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.
Select to expand quotehilly said..
At the cost of top end. Would be awesome in small waves but any decent swell might be a challenge.
We will see, but i think the selling point of the KDwilde design is that the top end is still good.Low stall speed at the cost of top end is no real mistery.
The section reminds me of supercritical airplane wings in a book on Aerodynamics i read back in the day.Probably just coincidence, apples and oranges.
en.m.wikipedia.org/wiki/Supercritical_airfoil
I have a good feeling about this one , CFD and America's Cup engineer whizzos are well and good but having a designer in the team that rides like KDW does is gold.
BTW the price is ok compared to the crazyness out there...
Select to expand quoteVelocicraptor 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.
In my opinion: The main benefit in new foils is wider speed ranges. Sounds like the KT's have a very wide speed range.
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.
Select to expand quoteMrFish said..
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
Do this KT foils have reflex?, those pics above are the underside not the top of the foil.
It seems they pack a lot of camber (concave) on the last third of the underside section.
Reflex would be the top side of the foil going from convex to concave on the exit right?
The word on the street seems to be that 'KT' have done a very good job with the Atlas
Select to expand quoteFaff said..Spark said..
Anyone gonna stock them in OZ?
SUNSNHINE COAST BOARD SPORTS CALOUNDRA.
Finally, the ice is gone and KT foils are flooding Europe. Had a long day trying foils: Atlas 790, Nomad 830, Nomad 700, Atlas 570. With a Dragonfly 95, and only the Atlas 570 I tried with a Super K 60. Used a shorter 56 cm fuse with all setups, and tried heaps of different shim settings with most of the front wings. The jury is still out if adding negative -0.5 or sometimes -1.0 feels better than the suggested way of calculating a shim. For Atlas 790 and for low wind I kind of found a much less draggy setting with extra -1.0. Well, let's see.
My initial impressions - all foils were super intuitive and really stable and predictable at higher speeds. Low wind feeling and getting going is quite a bit different compared to the foils I am used to. The feeling of drag in low wind is annoying, but at the same time it's totally understandable. - the KT fuselage is much chunkier (and of course stronger) than the Piuma fuselages I have been using, and also the KT mast is 3 mm thicker and with wider chord, which adds to that feeling.
Nothing much to see in the clip. 790 in the beginning, 830 at 01:05, 700 at 02:34, and 570 at 06:30. The other guy with a yellow dragonfly somewhere in the clip was with Atlas 960.
Even at 93kg I feel like the smallest Nomad, the 700, very easy to get up and going with just a bit of forward speed, so a smaller one for lighter riders would make sense. It feels quite fast to me and easy to roll, and carve, especially with the 155 tail. Glide is good enough for my needs too with the 170 tail. @Taavi, did you find much of a speed difference between the 570A and 700N? Is there any point in having both in the foil quiver in your opinion?
The biggest problem with the KT foils that I have been reading about and hearing about locally is that almost everyone wants the smaller size. Our local pro KT rider says that you need to size down one or two sizes for you to get exactly what you want. They ride much bigger than they appear,
Select to expand quoteWindoc said..
Even at 93kg I feel like the smallest Nomad, the 700, very easy to get up and going with just a bit of forward speed, so a smaller one for lighter riders would make sense. It feels quite fast to me and easy to roll, and carve, especially with the 155 tail. Glide is good enough for my needs too with the 170 tail. @Taavi, did you find much of a speed difference between the 570A and 700N? Is there any point in having both in the foil quiver in your opinion?
@Windoc, I made a few astonishingly slow "speed runs" today, my max speed with 680/145 was 38.7 km/h, 40.1 km/h with 570/145, and the fastest I saw with the 700/145 was 41.7 km/h. Used that very scientific method of just glancing at the watch when it felt fast enough : ) The strongest gusts were while riding with the 700. With the 570 the speed came really effortlessly, with 700 I needed to concentrate a bit. Quite a bit slower than I expected, but I am sure anybody with more courage and better conditions (and maybe with some extra kg as well) can easily ride faster. Super bad and gusty wind today, typical spring time 3-11 m/s I'd say. The feel of the 570 and 700 is quite different, well worth having both of course ; ) Another happy 3 hours in the water!
Thanks Taavi. My GPS wasn't uploading tracks for some reason after my last session, but the 700 could be pushed pretty effectively judging by the feeling and relative speed to others who ride at good speed. Where the 700 shines is feeling very comfy at any speed and being willing to change direction quickly and confidently. The low end is such a nice bonus.
My top speed with Atlas 680 was 42 kmh and I think it could go faster but I'm not really interested in speed (riding strapless). The 680 is now my daily driver. Really love that foil, I haven't touched my SK8s since then. While I think I could also use the 570 on most days, I resist to order it because I'm more interested in Wing surf and Wing downwind and the 680 is amazing for that and my skill level and conditions.
What surprised me most about the foil is how well it carves. Very precise like my SK8s, no turning over the yaw axis like many HA foils do. I use the long fuselage with 145 tail.
