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LEI power comparison with closed cell foil.

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Rannoch66
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LEI power comparison with closed cell foil.

Postby Rannoch66 » Fri May 03, 2019 1:25 pm

Hi everyone, I'm a newbie here, but I've been snow and land kiting for quite a few years. Just finally looking into getting started kitesurfing. Finally went to a beach in Tenerife to check it out and I was absolutely blown away by the sizes of kites these guys were flying... it was 22 knots out and it seemed the average size of kite in the air was 10-12qm. Not only that, but they were walking around the beach with the kites in the air and having no problems at all with control - no one was getting involuntarily lifted into the air.
I can only compare to the open cell foils I use for land and snow, and honestly, in 22 knots there is NO WAY I would be trying to fly a 12 qm kite unless I wanted to spend the session in the air! For me It would be a total death wish.
I know at the beach it's much less gusty than in the mountains, but still...I was just blown away that they were flying such large kites, and also that they seemed very controllable and stable.
Is this normal for kite surfing? Do LEI kites really generate that much less power and that much more stability than foils? Or is it more to do with having more depower than a foil?
I'd love to hear from some people that do both and what to expect in making the transition to water after learning on land & snow.
Thanks!

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Re: LEI power comparison with closed cell foil.

Postby kitexpert » Fri May 03, 2019 1:59 pm

LEI kites have only about 60% projected area (lifting area) of their nominal size while foils have usually about 80%. So 10m foil kite is actually a bit bigger than 12m LEI kite.

On the water more power is needed and also it can be controlled much easier than on land or snow. Many LEI kites have also more high wind capability than foil kites, they are usually easier to control in high winds. Last summer I was out with 9m LEI when wind suddenly increased to nearly 40knots in gusts. It wasn't at all pleasant and I had to trim my kite to almost full depower but I managed to get back in one piece.

cor
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Re: LEI power comparison with closed cell foil.

Postby cor » Fri May 03, 2019 2:00 pm

It has little to with LEI or Foil kite but more with the kite design (profile), your weight and your skill. Most modern LEIs and Foil kites in the size of 12m have enough depower to handle 22 knots or more. The more experience you gain, the more safe you will feel with bigger kites in those kind of winds.

I fly a 12m Evo up to 28 knots (more or less) if I want to go big on a TT and it's pure fun.

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Re: LEI power comparison with closed cell foil.

Postby grigorib » Fri May 03, 2019 2:07 pm

22 knots is when I 'll be riding a 9-11m LEI for a twintip session and on 5m LEI for foiling. Modern kites are powerful and predictable.
A myth that foils are more powerful than LEI is a matter of the past when comparing quad-line foil on handles to same size LEIs (since quad-line foils don't depower)
Otherwise I continuously been riding smaller sizes than guys on foils around me and they were on modern Souls, not something archaic.

On water in general you need more power and if you're on a twintip and boosting - you need even more power.
All being said the foils are usually staying in the air in the lightest of the winds (not that you will be able to ride them in 2-4 knots) and are usually higher aspect and loftier than usual LEIs.

grigorib
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Re: LEI power comparison with closed cell foil.

Postby grigorib » Fri May 03, 2019 2:11 pm

I think PMU can bring more content to the topic and lighten it up a bit
These users thanked the author grigorib for the post:
Pump me up (Sun May 05, 2019 12:29 am)
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cor
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Re: LEI power comparison with closed cell foil.

Postby cor » Fri May 03, 2019 2:37 pm

grigorib wrote:
Fri May 03, 2019 2:07 pm
A myth that foils are more powerful than LEI
It's not a myth. It's a fact. Foils allow designs with more projected area as just explained by Kitexpert.
grigorib wrote:
Fri May 03, 2019 2:07 pm
Otherwise I continuously been riding smaller sizes than guys on foils around me and they were on modern Souls, not something archaic.
You are mixing up power and high end. A "non archaic" Soul is more powerful than a same sized LEI in the same wind (just test it if you don't believe me! Because I did that already many times.). But that doesn't mean that a Soul has more High End than the LEI. And as already mentioned, the size not only depends on the design or profile, but mainly on your skill, weight and of course your style so what others are riding is merely an indication.

PS PMU incoming

grigorib
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Re: LEI power comparison with closed cell foil.

Postby grigorib » Fri May 03, 2019 3:01 pm

cor wrote:
Fri May 03, 2019 2:37 pm
grigorib wrote:
Fri May 03, 2019 2:07 pm
A myth that foils are more powerful than LEI
It's not a myth. It's a fact. Foils allow designs with more projected area as just explained by Kitexpert.

...weight and of course your style so what others are riding is merely an indication.

PS PMU incoming
My style is a lot of looping and downlooping and that's how I can extend range of my kite a lot and have more fun altogether.
That's the difference in style and that's how I squeeze a lot of power out of LEI and that's why I feel they're more powerful.

In static flight or static course more projected area is likely generating more power but even then - there are so many discussions about area of the kites not matching the numbers printed on them...

Let PMU bring the facts though

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Re: LEI power comparison with closed cell foil.

Postby SolarSet » Fri May 03, 2019 5:21 pm

You do know that foil kites can loop as well as LEI? Foils have unmatchable range due to high projected area, higher AR which makes them sit further on the edge of wind window

grigorib
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Re: LEI power comparison with closed cell foil.

Postby grigorib » Fri May 03, 2019 7:40 pm

SolarSet wrote:
Fri May 03, 2019 5:21 pm
You do know that foil kites can loop as well as LEI? Foils have unmatchable range due to high projected area, higher AR which makes them sit further on the edge of wind window
Foils do loop but amount of power you get from the loop leaves foil looping to be more of esthetic move.
Unless of course they bowtie and then we’re talking some extra propulsion.
There’s a good reason I sold all my foils to whoever rides snow or buggies and it were LEI which had unmatched range, not foils.

High aspect kites are special animals on their own, they do stay at the edge of the window and shoot upwind (both foil and LEI), they deliver floaty jumps and soft cushy landings, but going straight downwind on them - looping and figure-eight(ing) is a punchy nightmare sweeping the wing from one side to another. Also gusty winds (especially lulls) and HA kites are not best buddies.

Been there, done it, haven’t seen any revolutionary foil performance since. Sold a dozen of my foils and kept a couple to remind me why I sold the other ones.

Major kicks in the "foil nads" for me were:
- my Flysurfer Pulse2 8m folded into a mess falling down in a lull and then punched me by opening up as a chute in a following gust and dragged me on the shitty local beach, over concrete sidewalk, fortunately not reaching the trees
- I could ride Jimbo's Core XR 17m on 39m lines after my so-ultra-lightwind Speed3 DLX 19m wouldn’t get me on plane on my door anymore.
--I couldn't rig my foils on a tiny launch spot in Salvo and I didn't want to mess them up driftlaunching and self-landing with extensive packing/drying efforts
- I wouldn't driftlaunch/self-land foils in Rodanthe in gusty NE winds coming over the buildings and wouldn't drag the kite through muddy sound bottom to where they'd launch
- my Flysurfer Speed4 10m wouldn't fully depower/flag onto front line (no 5th line on mine) and was pulling me down the beach while (un)happily looping
- I wouldn't driftlaunch/self-land foils on our local spot where you need to wade water with kite in hands for 50 yards before you get to wind line and no obstructions on left side of the window (right side of the wind window are trees at the launch)
- my 10m Rally 2012 was so much more agile, powerful and had better range than Flysurfer Speed4 STD (2012 too). And it weighed the same 6.2lbs
- I happily rode my 15m Turbine in Rodanthe on 37m lines while guys with 21m Speed4 Lotus and 19m Speed3 ended way offshore and downwind
- I rode 15m Sonic FR and 15m Ozone R1 just as well as my 15m Turbine. Nice kites. I was glad I sold most of my foils by then.

And now, when I consider 9m "a large size" suitable either for boosting or lightwind foiling, my 7m/5m LEIs are my main kites, 11m stays in the bag. 15m Turbine is sold. Why would I bother about a foil kite?

But foils look pretty in the skies and with unlimited budget, steady winds and spacious launch/landing spots they’re awesome.
Last edited by grigorib on Fri May 03, 2019 11:44 pm, edited 2 times in total.

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Peter_Frank
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Re: LEI power comparison with closed cell foil.

Postby Peter_Frank » Fri May 03, 2019 10:58 pm

SolarSet wrote:
Fri May 03, 2019 5:21 pm
You do know that foil kites can loop as well as LEI? Foils have unmatchable range due to high projected area, higher AR which makes them sit further on the edge of wind window

Very true, foil kites DO have better low end than LEIs, and also higher high END, so more range.

But they turn slower, at least with more drag on the inside tip, particularly in the bigger sizes there is no comparison, and the very reason why most use LEI kites for freestyle and fun and waveriding.

For racing or jumping max, or foiling if not freestyle fun but range, foil kites are superior.

And when using smaller sizes for freestyle/fun one can use one or another, both types works well.

The reason why you see people standing on the beach with these kitesizes, no matter if a LEI or a foil kite (they approximately got the same high end for the same size, foil kites just a lot more low end as power when flown), is because they dont move, no speed at all.
And when on the water, you dont get as much speed as on snow, and one can hold the edge and control the power (and speed) a lot easier.
Finally, for land/snow kiting the wind can often be very gusty which might lift you unvoluntarily, whereas on the beach (and water) the wind is usually extremely stable compared to land/snow - which again gives the abílity to stand with bigger kites without being lofted :naughty:

8) Peter


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