Ralf Groesel and Bullshit Light Wind Claims

[Peter_Frank]

I was thinking that the easiest way to test the light wind ability of a kite would be to wait for a day with absolutely zero wind and on a large open sandy beach stand on the back of a truck going a constant 5mph (4knots) and see if the kite will fly? At that speed you could have people jogging with the kite with the lines taught for launch. I wouldnt be at all surprised if some kite companies have not done this already when testing the low end of their kites. Would certainly be a great promotion for a kite if it flew and finally settle the questions about kites flying in low wind. To test if there was also no wind at 20m you could put a wind meter on a long pole.

Well, no, not really.

What IS light wind ability?

The feature that they can hang in the lightest wind?
Or the feature that they can ride in the lightest wind?

Two completely different scenarios.

My experience says that:

One can fly a "normal" 5 strut LEI in 2 knots of wind, when flown actively on land, but not parked of course.

One can often fly a single skin kite, or a super UL foil kite in 2-4 knots of wind, parked.

But noone average weight can ride in this wind.

So it is not about how low you can go, in terms of having a kite fly, or fly parked.

Yes, it is great for us pushing the marginal wind limits, that the kite can hang easily when wind drops, so you dont have to loop it or pack down and swim ashore.

But apart from that, it makes almost no difference regarding how little wind you can ride in

The ultimate low end is your ability to keep the kite flying yes, but a lot more important, the ability to get max powerspike for the longest time.

Peter

[UKSurf]

I was thinking that the easiest way to test the light wind ability of a kite would be to wait for a day with absolutely zero wind and on a large open sandy beach stand on the back of a truck going a constant 5mph (4knots) and see if the kite will fly? At that speed you could have people jogging with the kite with the lines taught for launch. I wouldnt be at all surprised if some kite companies have not done this already when testing the low end of their kites. Would certainly be a great promotion for a kite if it flew and finally settle the questions about kites flying in low wind. To test if there was also no wind at 20m you could put a wind meter on a long pole.

Well, no, not really.

What IS light wind ability?

The feature that they can hang in the lightest wind?
Or the feature

I am just talking about the lowest wind the kite will hang in the air with stability. I dont expect to be able to ride in 4knots. But you might be able to get an idea if the kite would have the power to pull you onto your board with this experiment. You could see if there is the power to pull you onto the board by seeing if it can pull you onto your feet from a sitting position. The whole controversy about these 4/5 knot kites flying videos is the wind gradient etc this could settle that. Maybe Dimitri would be willing to do this with the Epic Infinity

[flaps1111]

It seems that the absolute minimum for an average rider 75-85 kg is 4-7 knots, that is minimum 4 knots and constant gusts 6-7 knots. The possibility of riding is due to the apparent wind and a foil big enough not to stall in the gybe where there is almost a moment of stop when you change the window at 12 o'clock. People talking about riding with a Peak4 o other kite in 4/5 knots I think they mean theirs kites hungs in that wind trying to water start, obviously they don't have a anemometer to know that a gust have hit their kite strong enough to pull them onto the board.

[Pump me up]

I was thinking that the easiest way to test the light wind ability of a kite would be to wait for a day with absolutely zero wind and on a large open sandy beach stand on the back of a truck going a constant 5mph (4knots) and see if the kite will fly? At that speed you could have people jogging with the kite with the lines taught for launch. I wouldnt be at all surprised if some kite companies have not done this already when testing the low end of their kites. Would certainly be a great promotion for a kite if it flew and finally settle the questions about kites flying in low wind. To test if there was also no wind at 20m you could put a wind meter on a long pole.

Great suggestion UKSurf. We all know that videos or photos of kites flying at supposedly low wind ranges (e.g. 4 knots) are notoriously unreliable, to the point of being useless, because nobody knows what the actual wind speed is, particularly at 20 m height (https://en.wikipedia.org/wiki/Wind_gradient). But just to clarify your numbers: 4 knots is actually 4.6 mph, not 5 mph, which is close to the average walking speed. Most kites won't even fly at this speed, let alone generate traction power.

[PullStrings]

No one ever gets excited when they get to the beach and the wind is only 4 knots
Plus if 4 knots is the average wind speed then it really 3 to 5 knots

Yep i have been in dozens of extra light wind sessions
I can recognize certain wind direction ( side to side on) and water temperature ( cool to cold) and wind temperature ( warm to hot)
When all those three are present and the water is like glass i know i should rig up = steady wind flow will be dense and gradient
Of course it will not be 4 knots average at head level but more like 5.5 knots ( estimated from experience)
Once the kite launches and gets to 20 meters it feels double like 11 knots
Then once on the water i will get immediately on a plane with wide surfboard + 17m tube
The wind power now feels like 13 knots will all the apparent wind created from moving quickly
Surreal yes
Would i claim that i rode in 5.5 knots ?
Of course not

I think people who generally live in windy locations get the low wind speed "number" wrong
Those who live and ride generally in light wind locations often get it much better

So if you get a magical session take notes about all the elements that came into place for that session
It is usually not only about the speed of the wind

[Regis-de-giens]

I was thinking that the easiest way to test the light wind ability of a kite would be to wait for a day with absolutely zero wind and on a large open sandy beach stand on the back of a truck going a constant 5mph (4knots) and see if the kite will fly? At that speed you could have people jogging with the kite with the lines taught for launch. I wouldnt be at all surprised if some kite companies have not done this already when testing the low end of their kites. Would certainly be a great promotion for a kite if it flew and finally settle the questions about kites flying in low wind. To test if there was also no wind at 20m you could put a wind meter on a long pole.

I agreee with you regarding the evaluation of kite ability to stay in the air; and (as said above) very few kites from my various tests can be flown just by walking / running backward; you can add another interesting exercise : lower the kite as for a ride and turning around (still walking backward) during a full 360 degree turn of you and the kite;


This averages the real wind during the test and this also shows if the kite has a good "lateral lift" ability, which is important for light wind sessions .
And not only : with a bit of math, you can deduce an approximation of the kite L/D ratio (from the radius of your circle during the run vs line length) which helps generating speed during your ride. So, excellent for your legs and heart bit also to assess / compare kite characteristics . Very energy consuming but interesting.

[Flyingseb]

But just to clarify your numbers: 4 knots is actually 4.6 mph, not 5 mph, which is close to the average walking speed. Most kites won't even fly at this speed, let alone generate traction power.

4 mph is 7,4 kph: sorry but this is a lot more than regular “walking speed”. It is even jogging speed for some!
For sure, kites won’t generate power at that speed anyway, but that is not the point. The point is: are they able to stay stable in the air with no input?
To generate power, they need to be moved across the wind window, to generate apparent wind, which does create lift in return. For that reason too, a smaller kite, which can fly fast, can generate lots of power.
But small kites have got their drawbacks: their “wing loading” is inherently higher, thus staying aloft less good in low wind.

[knyfe]

Oh good point. I want to see a walking 360 with a tube! Is there a video of a LEI anywhere? I have seen LEI on ice 360 - I think it was even a Cloud. But never a walking 360 like with the elf (and other foils as well)

[Soleas]

If they achived the same weight as foil kites (ramairs for you dear friend pumpy ) then i believe it could be possible. Ofcourse the 4kn claim in a kite advertisment is not right since the average rider will think that just the kite will magicly pull him in 4 kn which it definetly won't but I believe a skilled experienced foil rider could do it.

I landboard in 2-5knots on a 10m foil kite. I never believed it could be done my self also, until I tried it. The kite cannot stay flying by it self. I need to walk back fast to launch and jump on the board straight away and go and as soon as i pick up speed it works. On a hard salt lake surface only ofcourse, not grass or sand. And with 22 years of flying experience.

I never tried a foil board. Does it have less friction than a landboard on a hard surface? If it does or has similar friction or resistance then it is possible if you keep the kite flying with board speed.

I agree with you on the exageration. But it is possible.

[leeuwen]

I landboard in 2-5knots on a 10m foil kite.
…

I never tried a foil board.
Does it have less friction than a landboard on a hard surface?

The friction while riding is irrelevant, it’s not what decides the low end on a hydrofoil.

Unlike a land board you cannot just step on the board and potentially even give it some starting speed.
You need enough energy from the kite to be able to get on the board and up to foiling speed.
Also just keeping the kite in the air while maneuvering out in to deep water and getting into a starting position will become tricky.