Kt boards

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north_kiter said..
Anyone with sailing or surfing experience knows that a longer water line length is faster which means the foil will engage faster.
With this design they dramatically shortened the water line length, it's actually comical.

I'd like to demo it for a laugh but I'd never pay 1 cent for this board

Ever heard of Axopar boats? Do you think Keith Teboul is clueless? Do you think they released this without doing any testing?
Time will tell.

Sure why don't you guys buy one and let me know how it goes. What has Axopar boats got to do with this board design?

I'd love to see sales figures in a years time in Australia, but I'd wager it'd be 1 or 2.

I don't need to be a board design expert to spot a dud. If it looks like a duck and sounds like a duck then chances are it is a duck.

I've owned a KT drifter but definitely won't be owning one of these.

Kai Lenny is a gifted rider for sure, doesn't make him a board design expert. Are you saying he tested this and has his endorsement? I still wouldn't buy it if he did and haven't ever bought a board because Kai Lenny said it was good.

You probably have lost that wager already.
Considering the "shiny new toy" malaise this collective suffers there is probably a dozen preorders by now.

Waterline,btw, is unaffected by the step.That tsil is gonna be in the water when schlogging.

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foilthegreats said..
Looks like they have Patented, US No. 11,027,796, EU No. 22020001-8

This would indicate to me this design is not just some marketing razzle dazzle.

You can find the hype sheet and info here on the board: ktsurfing.com/boards-2022/ginxu/

I'm afraid that that's not a EU (EPO) patent number. Probably its one of a member state with aspirations to concert it to EU.

i've read the us patent. Their 'invention' start to makes sense to me be, but that's because their invention is something I'm familiar with from windsurf and windfoil.

check out this section from the us patent:

"The contact of the board along the surface of the water creates adhesion between the planing surface of the board and the surface of the water, which further causes drag. This adhesion must overcome for the board to ultimately leave the surface of the water to thereby eliminate the drag. These forces act to constrain the board from detaching from the water and/or actively act to attach the board to the surface of the water. Since the planing surface is typically continuous and even from nose to tail, this creates a relatively large surface area to adhere to the surface of the water. As the board gains more speed, the hydrofoil assembly provides more upward force, or "lift", and the board is able to break the adhesion from the surface of the water. However, given the relatively large surface area created by the typical configuration of the planing surface, the board must achieve considerable speed before the bottom of the board can break the adhesion with the water. Manually gaining such speed by paddling, or through the power of a wing, kite, sail, and/or propulsion system may be difficult for the average recreational user given the drag, and may still be difficult or take longer than desired for professional riders of the highest physical fitness. In some instances, gaining the requisite speed may require a relatively larger, more powerful kite, sail, wing, foil and/or propulsion system, and/or steep wave to assist in propelling the board."

Basically the problem and solution they describe, are the cutouts almost all windfoil boards have and a lot of speed oriented windsurf boards. The only difference here is that it has one massive cutout, but that doesn't make it innovative. Would be interesting to see if this patent would survive an opposition procedure. There's quite some elements to counter their invention (in EU) based on a lack of novelty.

Enough off the geek stuff. It has attracted my interest. Makes me think why cutouts haven't really been popular in wingfoil boards.

From their website
"Most surprisingly of all it makes it incredibly easy to initially take off, because the moment you get a little bit of speed on the water and the board starts to rise to the waters' surface, even though the front 2/3rds of the bottom of the board is still in the water, the foil is already out of the water and flying, creating an Ultra Boost, getting you going much quicker than traditional designs."

I don't think that is an accurate statement to make when the board is still on the surface of the water the foil is flying.

What is the definition of a foil wing flying?

- Lift to balance the force of gravity
- Thrust to counter the force of drag (resistance) - without thrust, an object will lose its forward momentum

Now the board still has contact to the water, so that is not flying. It's like saying a plane with it's wheels still touching the ground is flying.

Sounds like marketing mumbo jumbo to me, and it costs roughly 3.5K AUD

I've always wondered what kind of drag penalty we are all carrying around with the mastplate and fasteners - on my last board I had both tuttle and plate mounts and I for sure could tell the reduced drag from using the gofoil tuttle mast versus the pedestal style. It is quite possible that the step puts the foil pedestal in the turbulent flow and reduces that drag penalty. but the reduction in running length seems like quite an issue

I've heard testing feedback and it apparently works amazing for anything involving planing. It's essentially a "higher aspect" lifting surface that will have much less drag at planing speeds. Check out some videos of professional skimboarders for a good example of this in action; by turning the board sideways they can extend their glide significantly. This should mean it sticks a lot less when touching down.
The step also creates a pivot point in pitch when the board is touching down, which could help pump off the water and un-stick the board. I imagine this is incredible for jumping.
Most of the current or older KT foil boards are also pretty sticky, especially Kai's personal boards. This is probably a massive improvement over that.
My guess is this will work awesome when given enough power or big enough foil to get the step to release quickly. It probably won't beat Dave Kalama's displacement shape for large downwind boards but could excel in smaller sizes. I'm really interested in what happens in the mid size range (65-85L).
They've been working on this concept for a while and clearly found some improvement. Im really excited to try one!

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jondrums said..
I've always wondered what kind of drag penalty we are all carrying around with the mastplate and fasteners - on my last board I had both tuttle and plate mounts and I for sure could tell the reduced drag from using the gofoil tuttle mast versus the pedestal style. It is quite possible that the step puts the foil pedestal in the turbulent flow and reduces that drag penalty. but the reduction in running length seems like quite an issue

Parasite drag (form+friction) is proportional to speed squared, so at takeoff speeds the drag is probably low but in a high speed touchdown it is for sure very big.

No idea if at low (takeoff) speeds the step will reduce the form drag of the plate enough to compensate for the form drag of the step itself.Guesstimate it does not.

The reduced volume and structural weak point (in the worst place possible) could be reduced by making the step only as wide as the mast plate.With the bottom sides uninterrupted to the tail.This would "hide" the plate just as well.

But i would think they have tried this and many combinations in between and the full step came out best.

Of course what is best for Kai Lenny may be disastrous for me :).

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omg said..
I have this one coming

Now that's a better design, an attempt to hide the mast plate, but keep a smooth flat bottom edge

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FoilAddict said..

Most of the current or older KT foil boards are also pretty sticky, especially Kai's personal boards. This is probably a massive improvement over that.

This is not what I have experienced with the KT / Quatro foil boards. They don't feel sticky at all.

Sorry, can't provide evidence as I just registered and can't post links. If anybody wants to see my experience with the Quatro Wing drifter 80 L, KT Drifter S 40 litres, and now with the Ginxu prototypes, well let's hope the restriction of posting links to videos will be removed soon.cheers
Taavi

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omg said..
I have this one coming

The Aero board construction is pretty great. Used the previous model quite a bit, a 5' 80 liter board that weighs 10#, seemed pretty tough too. This newer bottom shape was just coming online, would've liked to try it. If the price hadn't gone up like 25%, I would've bought one.
Being made in Poland that's getting pretty close to the front lines. www.aeroboards.com/

Cool, how quickly does the 54l get on the foil, I have a 65L takuma tk and am interested in either the 62 or the 54.

Mike

Kai's IG post today mentions 2 years of testing the Ginxu design: www.instagram.com/tv/CbqvjpVJb4L/?utm_medium=copy_link

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baldy123 said..
I'd be keen to try one of these new KT boards. However, I don't think we will see many in West Oz. One thing I think is needed in wing board design is longer foil tracks. Everyone is mixing and matching brands everywhere and industry norm needs to be 12-14" boxes. Armstrong started the trend with their carbon track system in the FG boards. The new JP Australia Wing board tracks are huge. I also hear Sunova will be adding 14" tracks all wing boards and SUPs in the coming year.

Yes, I sold my Sunova as it felt mis-matched for Armstrong. Love the long Armie tracks, though even for the new FG boards I'm running mast really far forward. Longer tracks in other brands would be welcome for sure.

For those who speak a bit of french, here's a video of Keith explaining the features and construction.
sounds to me like this board was tested mostly in the waves and I can see how the push of some swell along with a board with minimal wet surface could complement each other.

@Taavi, any thoughts on this board vs a board with a more traditional tail?