I never really hear people talk about wing tip lift when windfoiling, i.e. when the end of the wing lifts above the water surface during gybing or going upwind in chop. It seems to me that it has a massive effect on the riding experience.

I regularly sail with Slingshot infinity and Lokefoil LK1 wings. Here's two wings that have comparable performance in terms of take off and stall speed:


The top wing is the Lokefoil 1200cm2 wing with a wingspan of 92cm and the lower wing is the Infinity 76cm (area 1500 cm2). Both are used on masts around 90cm with the same board.

If I use the Lokefoil I have to be really careful not to carve too much as the wing tip lifts easily and it results in a severe lost of control or even crash. Whereas with the Infinity 76 I can carve a much tighter radius without lifting a wing tip. This becomes even more noticeable in large chop where I've got the board close to the water but can still lift a wing tip in a trough.

If the Slingshot wing tip does lift I normally hear it first and there's much less loss of control. I assume that's because it has a smaller wingspan and the tips don't generate much lift due to the twist in the wing and their relatively small area. Anyone else noticed this?

Just in general, any time a wing, or any part of a wing, is out of the water, yes, the whole world changes a lot.

I foil with both low AR (i76) and high AR (AFS-2 and Moses Race) foils. The low AR foil has a nice mushy stall while the high AR foils have a very sharp and dramatic stall. Also the low AR foil, like the OP says, breaches so that you can hear it before you feel it.

The best way to keep the entire wing under water is to foil with a long mast.

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simonp123 said..
I never really hear people talk about wing tip lift when windfoiling, i.e. when the end of the wing lifts above the water surface during gybing or going upwind in chop. It seems to me that it has a massive effect on the riding experience.

I regularly sail with Slingshot infinity and Lokefoil LK1 wings. Here's two wings that have comparable performance in terms of take off and stall speed:


The top wing is the Lokefoil 1200cm2 wing with a wingspan of 92cm and the lower wing is the Infinity 76cm (area 1500 cm2). Both are used on masts around 90cm with the same board.

If I use the Lokefoil I have to be really careful not to carve too much as the wing tip lifts easily and it results in a severe lost of control or even crash. Whereas with the Infinity 76 I can carve a much tighter radius without lifting a wing tip. This becomes even more noticeable in large chop where I've got the board close to the water but can still lift a wing tip in a trough.

If the Slingshot wing tip does lift I normally hear it first and there's much less loss of control. I assume that's because it has a smaller wingspan and the tips don't generate much lift due to the twist in the wing and their relatively small area. Anyone else noticed this?

Yes, the SS does have twisted wing tips and most of the lift is generated in the middle sections of it. And, as Segler correctly pointed out, who gets to the surface of the water sooner matters. It may be that the more turned tips of the SS also inhibit sideways flow on the wing so if it does get close to the surface, the underside pressure loss isn't as abrupt or extreme. I have noticed that my flat wings of similar area seem to be slightly more prone to ventilation than ones with curved tips.

It's also worth noting the i76 has 25% more wing area so the wing loading is significantly less. If both wings were designed identically, the smaller wing would support a 70 kg rider the same way the larger would support an 88 kg rider. That's a noticeable difference - and why I get leery of 100 kg guys making wing recommendations to 65 and 70 kg riders with blanket statements.

And let's flip that around for a moment - a wing that has 25% less wing area has the same take off and stall speed. That's why my AFS F800 brings me joy at it's seemingly small 1100cm2 area.

btw, new Loke wings coming out for LK1. Downward sweep it tips should help keep them submerged

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