Smallest possible LEI kite size for best low end

[Qiter]

Some foilers (like me) are not into foil kites so the low end of LEI kites becomes a big argument when choosing new quiver. Obviously, for freestyle, you will always want to fly the smallest possible kite, as size makes a big difference in maneuverability but on the other hand you need to get going in marginal conditions.
In this context, I have realized lately that the low end of my 12m LEI is not much different to the low end of the same model in 9m (North Mono), maybe 1-2kn. I guess the speed of the 9m makes up for the lacking surface area?
With the 12, I can go in 6-7kn, maybe a bit below if its not too gusty and I comfortably use my 9m from steady 8-9kn onwards. So the range for the 12m is tiny (about 2kn).

So now when upgrading to new quiver, I wonder if I even need a 12m anymore? Can I go smaller? My homespot conditions are often between 5-10kn, so the low end is important for me.

Does anyone has experience with this? I am not asking kite brands and models (I am into one-struts, as they are light and therefore suitable for marginal conditions, I know most of models..), but more the concept:
How much low end do I loose if I go with 11m or 10m instead of 12m? (same board and wing, of course)..

P.S: I consider myself an advanced foiler (mastering most foiling manoueuvers jibes, tacks, 360, 180 etc etc.)

Thanks a lot!

[plummet]

I guess the answer is going to be demo demo demo.
Also how underpowered do you like to be? I know i can ride my 8m down to 9-10 knots. But i'm bored sub 13 knots on that kite so I yearn for a bigger kite to be more powered.

Personally, i really like my 12m chrono for sub 13 knot stuff. I like to be powered and i dont mind changing my style to suit the more powered, slower kite more race style speed and cranking of the high aspect foil.

I think if you want to undergo a 10m 5-10 knot journey you may need to look at a bigger foil to offset the smaller kite. I recon 8 knots is most likely doable on a 10m lei, but 5-8 knots is going to be a real underpowered strugglefest unless you have the big surface area foil to support less kite.

[tomtom]

On big wing power isnt issue at all. Issue is relaunch and stability in lull. I personaly at 90 kg and moses 633 had almost no benefit from NEO 9 to Mono 12 - both are limited by lull stability and relaunch. I use 9m foil kite for LW and go straight to 7 LEI. I did not try very light zero mono struts like BRM. Mono isnt light kite. 5knts is not LEIable imo.

[tkaraszewski]

My low-wind kite this season has been a 10m Flysurfer Soul (which I know isn't what you want, but that's not the point), which I feel like is good down to about 11 knots, and after that it's too light for me to use it reliably. On the other hand, my mid-range kite is a 7m F-One bandit, which I can ride down to about 13 knots, so same as you, the extra 3 meters only buys me about 2 extra knots of wind. With better technique maybe I could get an extra knot or two out of this, but I don't like kiting so close to the edge that any tiny mistake results in a dropped and non-relaunchable kite. I could also maybe get an extra knot of low-end by going to a lighter single strut kite. I'd rather wait for the wind to come up an extra knot or two. I also usually kite in higher-wind locations.

I think that even in smaller kite sizes, you can almost always build enough power to foil, as long as you can keep your kite in the air. I think what helps with this at the very low-end is a very lightweight kite. If it's blowing right around the minimum to keep your kite flying (say 8 knots for some hypothetical kite), a short lull to 7 knots can put your kite in the water if you lose any board speed. A lightweight kite will float in the air with less wind than a heavier kite that's otherwise equivalent.

You get diminishing returns with bigger kites, because the force of the wind is proportional to the square of it's speed, so if you double the kite size, you can "catch" twice as much wind, but if you double the wind speed, the wind has 4x as much power. The converse of this is that if the wind drops by half, you need 4x as much kite for the same power, so at the bottom end of the range, kite sizes have to increase by huge amounts to keep up with small decreases in wind speed.

Anyway, it seems like most people can ride a 9-10m in 10-12 knots if wind and be happy with it, but I think a lot of pushing the limits of the bottom end of the wind range is down to technique, and never letting the apparent wind on the kite get so low that it can't keep flying. If you're good at this, you can probably keep the effective speed a little bit higher than someone who's not as good at it, thus letting you use a bit smaller kite.

Anyway, it sounds like you're a better foiler than me (I'm planning to try and learn tacks this summer), so I'd expect you can get an extra knot or two lower than I can (which is what it sounds like), and a 9-10m might be big enough for you even at the low-end (I wouldn't even bother trying to kite in 6 knots, but I live in a location known for big winds).

Finally though, what does the math say?

If the power of the wind is proportional to it's speed squared, but the power of a kite is proportional to it's area, then you need 20% more power to fly a 10m over a 12 meter, which means you need about 1.1x the wind speed, which means if you can fly a 12 in 7 knots, then you can fly a 10 in 7.7 knots.

This math also suggests that if you can fly a 12 in 7 knots, you can fly a 9 in 8.1 knots, and a 6 in 9.9 knots. This math is too simple to count things like the relative weight of the kite per area at any given speed, though. Aerodynamics is hard.

Anyway, that was a whole lot of text to say "going from a 12 to a 10 probably only costs you about 1 knot of bottom end wind speed".

[TomW]

There's a local foiler riding and selling the storm Voyagers. He's often out on the big sizes in low winds. Even the 15.

[Qiter]

Finally though, what does the math say?

If the power of the wind is proportional to it's speed squared, but the power of a kite is proportional to it's area, then you need 20% more power to fly a 10m over a 12 meter, which means you need about 1.1x the wind speed, which means if you can fly a 12 in 7 knots, then you can fly a 10 in 7.7 knots.

This math also suggests that if you can fly a 12 in 7 knots, you can fly a 9 in 8.1 knots, and a 6 in 9.9 knots. This math is too simple to count things like the relative weight of the kite per area at any given speed, though. Aerodynamics is hard.

Anyway, that was a whole lot of text to say "going from a 12 to a 10 probably only costs you about 1 knot of bottom end wind speed".

This is exactly what I was looking for, thanks a lot! It matches the experience I described above (but I was not sure if it was just my impression or "for real" and what the true numbers were..).
So it seems that going from 12 to 11 will not be such a big deal, I might loose some decimals on the surface side but maybe gain it on the speed side if the kite is fast enough (and thereby generates some more apparent wind..).

Wing-wise, I am on the 633 Onda, so no problem.
Relaunch is not important for me, I am prepared to swim if I go out in marginal conditions, its part of the game.
I know I can use a big kite in low winds, no problems. But this is not what I want. I am into freestyle and the smaller the kite, the easier it is to maneuver it.

When I started foiling a few years back, I was on the 15m most of the time, then, after about 1 year, the 12m became my most used kite and now its the 9m. Conditions unchanged at my homespot.. I guess it shows you also how when you progress, you can go to smaller and smaller kites.

[mcfly777]

One other thing that I'll look into for my next kite is to get a kite that has power when it loops. I have a Cab FX and the power is not great during loops, so for waterstarts when i backloop there's no huge advantage. I love the fast looping aspect of it, but i'd like to have more power (and that's also why the BRM Clouds didn't work for me, they pivot quickly and low power).

[Cefirmeza]

I guess the difference from a 9m LEI to a 12m foil kite would be worth on a regular light wind place.

The 9m on long lines get me going on my 63kg until 9-10 knots I guess but I´m looking for the lowest end and I thing I would go for a foil kite just don´t know the size yet.

Any thoughts?

[AndersP]

One other thing that I'll look into for my next kite is to get a kite that has power when it loops. I have a Cab FX and the power is not great during loops, so for waterstarts when i backloop there's no huge advantage. I love the fast looping aspect of it, but i'd like to have more power (and that's also why the BRM Clouds didn't work for me, they pivot quickly and low power).

What if you try longer lines and a bigger loop? You don't have to loop tight just because you can.

[bigtone667]

Long lines make a huge difference during re-launch. I moved from 20m lines and 13 m kite to 32m lines and 10m kite.