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Speed 3 21m Upwind adjustment

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foilholio
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Re: Speed 3 21m Upwind adjustment

Postby foilholio » Fri Jul 29, 2016 5:07 pm

kitexpert wrote:WTF? You mean your observation is that 21m kite is bigger (thicker) than say 9m kite? "Absolute thickness" :lol: :lol:
I'll forgive you because you say english is your second language, but trust me I would not be the one laughing if i was you and try to learn english a bit better.


kitexpert wrote: higher camber..... are more efficient.
Again I forgive you because of your english and maybe you don't know what you are typing. But I have explained and proven that this incorrect. Go back and read again what I posted. Feel free to ask me if there is something you are not sure about.
kitexpert wrote: :lol: Your examples are "tweaked" ones.
Not at all, if you can read them correctly the links are there and you can see the context. There is a lot more information available too. The real world is also available 24/7 to test any statements or theories.
kitexpert wrote: Using flaps is much the same than tightening very much brakes - of course it lowers L/D, it causes huge drag. I have not suggested anything like that, but using higher camber airfoils to get more efficient kites.


Flaps increase camber and are as such "higher camber airfoils". There is a youtube link there showing tests from 1938 of cambered airfoils, well flat plates they call them but they are still airfoils. You can see the actually increase drag created by them. You can not increase lift without drag. Lowest L/D is at low lift though..... There is actually a discussion there that talks about actually lift or glide rate and that is actually better at higher L/D, so low camber, low AoA and higher speeds.
kitexpert wrote: Stop arguing against known facts, foilholio.
I am not. You are arguing in the face of facts presented to you. I have actually observed these things to be true in the real world from experience. Which is actually where the term expert comes from, the latin experiri or to try. There is things I have tried that you have not and there is also things you have tried which I have not. We can learn from each other.

kitexpert wrote: Or have a test with some wind tunnel program: take some airfoil and change it's camber. You will see when you increase the camber airfoils efficiency - both L and L/D - will increase.


Sure but is it a high amount of camber? is it at all windspeeds and AoAs? Is the program accurate?
kitexpert wrote: I did quite a lot that kind of study ten years ago


Congratulations, it takes some of us a while and a lot of effort but we can learn. You do know incorrect theories of lift were still being banded around 10 years ago?

kitexpert wrote: and I dare to say I know which airfoils are suitable for kites


I doubt that based on the statements you make. Like why a kite needs not weight less than a certain amount or how higher camber gives better L/D ,etc etc all incorrect. I am sure you are actually a failed kite designer, used to to do work for some brand. Just a guess :-) Like most of the rubbish of past years I bet you are convinced of the benefits of giant tubes and massive luff curves, hence your repeated incorrect assertions about high camber have good L/D. You probably sold the same bullshit to your bosses, well one they woke up to your bullshit and out you go. BYE BYE. But do you know what you can actually be right, you can learn what is actually the correct understanding. you just need not be so arrogant and just be a little humble and think hmm maybe i could be wrong, and lets have a look at it again.

BTW I can see why you hate on Greg so much, the guy has gone against the collective bullshit of you and the likes and without the fancy degrees and years of study come up with a kick arse kite. I think your tea cup is too full. :-)
kitexpert wrote: Of course they all use cambered airfoils.
Of course, square structures are too draggy and flat ones too flexible. One must use curves, such is the natural world and a very pretty one it can be. Smile !

foilholio
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Re: Speed 3 21m Upwind adjustment

Postby foilholio » Fri Jul 29, 2016 5:23 pm

Regis-de-giens wrote:Please, let exclude backstall cases were everybody honestly do not car about the L/D ratio , right ? :D vonlunaty backstall is just a kind of exceptional configuration (for which standard kite bar control even do not allow) and were it may just be a way to relocate the foil elsewere int the wind window, not a "upwind ride configuration".
hehehe :-) I do use it as you can sail downwind with the kite parked downwind. Like a spinnaker.
foilholio wrote: I admit I am still learning on the fly here :-) how exactly tow points and CoP and moments interact to cause window position changes is not 100% with me, though If I think about it I can explain it better, it is just forces finding some equilibrium. It does prove hard finding written explanations but there is some, I think kites are a bit fringe in the aerodynamic field. At most it seems a towpoint creates another point for forces to act around or from, like the CoP, AC, and CG.
Regis-de-giens wrote:The position of the kite is more simple that that (at least as a first approximation which is enough for us). Let's seen it differently from how it is "commonly" described (it is worth a dedicated topic, but I hope you will excuse this off-topic): during a ride with constant vertical angle of the kite vs the rider (i.e. not working the kite), the foil is ALWAYS at the extreme of the wind window, and the kite does not really go deeper in the wind window (don't shout too rapidly, just give me 1 minute...):
I CAN"T RESIST RABBLE RABBLE RABBLE. ok continue.

Regis-de-giens wrote:The feeling that it goes deeper is due to the fact that the "speed" wind changes the direction of the total (apparent) wind seen by the kite, i.e. the total wind will come more from the front of the rider direction (due to speed wind parallel to rider speed). So it is still the extremity of the kite wind window, but now taking into account the wind that the kite really see coming from your direction angle, i.e. the modified direction of the wind. It also means that if you would send the kite in the opposite window ( and if you have still enough speed), then the kite will go beyond the 90 degree, say 100 or 110 degree backward you :D , up to the rider having zero speed and come back to 90 degree.

So if you understand that and agree with, then the position of the kite is only given by the L/D ratio of the kite (at the instant AoA imposed by the bar position) and the ratio of the rider speed vs real wind speed at ground.
No I understand how apparent wind works and the window changes. But how does the kite choose it's exact position in the window taking all of the aerodynamic factors into account not just a few. I am thinking it moves till the CoP matches the tow point or keeps trying. Or maybe as well it is the angle of the tow point and position are trying to align with the angle and position of the CoP. That makes sense. Two forces in balance, Thoughts? I guess the CG moves it a little off, but the moment hmm. I bet peterlynn could explain it.

kitexpert
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Re: Speed 3 21m Upwind adjustment

Postby kitexpert » Fri Jul 29, 2016 7:07 pm

Foilholio, your high cambered examples using flaps are a typical "straw man" argumentation. I have never meant anything like it when I've explained the better efficiency of cambered airfoils.

English is more my third language than second. But I have no difficulties to understand most of what I read from this forum and I think I can write understandable enough. In kite design my first language is english because programs and terms are in english. But I must say I do have regular difficulties to understand your postings, foilholio :D
foilholio wrote:Sure but is it a high amount of camber? is it at all windspeeds and AoAs? Is the program accurate?
I don't think there is any reasons to doubt these programs. I have not studied every possible situation, but have limited only Reynolds No's and AoA's which are reasonable for kites. And no extremities of camber, negative or positive. There is enough work here anyway. But like I wrote earlier: it is wise to know what kind of airfoils are generally used, no designer is such a fool who starts from zero.
foilholio wrote:it takes some of us a while and a lot of effort but we can learn.
Wise words, foilholio :lol: You must first unlearn false opinions. It very strongly seems to me that you don't have solid basics to build your knowledge of kites. That is why you tweak and tinker so much and try different mixers etc and have strange views of AoA's and airfoil cambers..
foilholio wrote:I can see why you hate on Greg so much
I don't hate that man at all. He makes simple kites which are apparently very suitable for his needs. And he is great with hydrofoil. However my ideal kites are very different: race foils, fast upwind, big air and user friendly tubes for high winds. As a designer I think I'm much closer to Harich, Hansen and Whittall, their work and presentation is more sound, more ambitious and more based on physics than Greg's.
foilholio wrote:come up with a kick arse kite.
Clouds lose against effective kites in jumping, hangtime and upwind. It has quite flat canopy (low camber) and low AR, so it has low L/D. If I remember it correct, he explains this in youtube. Advantage is to kill pull totally if needed (with very long sheeting range), good drift and powerless turns.

foilholio
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Re: Speed 3 21m Upwind adjustment

Postby foilholio » Sat Jul 30, 2016 2:06 am

kitexpert wrote:Foilholio, your high cambered examples using flaps
Thankyou yes they are high cambered and also have poor L/D. The opposite of what you stated.

kitexpert wrote:English is more my third language than second.


Maybe it is just the misuse or understanding of a couple of words you have, like high or best.
kitexpert wrote: I have not studied every possible situation
I would believe that and neither have I, but I have what I have read and observed to go on. I obviously have observed things to be different than you have.
kitexpert wrote: it is wise to know what kind of airfoils are generally used, no designer is such a fool who starts from zero.
True one must account for the design speed and lift needed and no doubt camber is needed the more lift you require. Kites are unique because they have low weight and lift requirements and are only speed limited by themselves. As such thin airfoils with low camber, which are inherently efficient work well. Kites that choose thicker airfoils and camber become range limited and have poor performance. One of course needs to know how to fly such high performance airfoils, one can not merely park the kite and hope it will go well. For the beginner and general idiot ,who the kite companies market to, fat airfoil/tube/luff is a desirable quality because he has no clue. There is of course other structural design reasons to choose a thicker structure but aerodynamic efficiency is not one of them. To become deluded that such is so is bad for the mind.
kitexpert wrote:Wise words, foilholio. You must first unlearn false opinions.


Thankyou are yes I can be wrong and so can you as I have pointed out.
kitexpert wrote:It very strongly seems to me that you don't have solid basics to build your knowledge of kites.


I don't think so , I think I have a fair understanding and better than most, better than you in some areas.
kitexpert wrote:That is why you tweak and tinker so much and try different mixers etc


I don't actually spend that much time, my understanding is enough now that I know most what and why and how, what changes what. I still have somethings to learn like span wise effects, but I suspect even flysurfer is just starting to grapple with that, looking at their evolution of arcs. It is complicated moving from a 2d theory to a 3d one.
kitexpert wrote:and have strange views of AoA's and airfoil cambers
I wouldn't expect you to hold any other opinion. :lol: Like a cave man looking at fire you are both intrigued and scared, a range of emotions must beset you.
kitexpert wrote:I don't hate that man at all.
You have a strange way of representing that.
kitexpert wrote:He makes simple kites
Case in point, true though it may be, perhaps refined is better used when you discuss that you don't hate him just before. Simple can be an offensive term.
kitexpert wrote:However my ideal kites are very different
As it is for everyone.
kitexpert wrote: race foils, fast upwind, big air and user friendly tubes
Two kites that could not be more apart. It is like you have a split mind, interesting.
kitexpert wrote: As a designer I think I'm much closer to Harich, Hansen and Whittall
You talking about people by just their surnames is actually belittling them.
kitexpert wrote:their work and presentation is more sound, more ambitious
not really, their work is generally quite safe and based on knowledge obtained from paragliders risking their lives. You need to look at who at flysurfer is doing the most cutting edge development. I would say the product is the peak and the designer is Reinhart. I think he is largely self taught like a certain Peter Lynn. The safe kite ,although cutting edge for inflatables, but just borrows from their other kites, is the boost. The highly educated designer Andi Hanrieder seems to have disappeared. I asked Armin about that and he didn't reply.

foilholio wrote:and more based on physics than Greg's.
Sure you don't hate him, keep going.

One thing is true new things are not discovered by accepting that the old are all there is, or 100% correct. Greg has a good understanding of things, better than most and better than you too in some areas. I don't think you understand his kites, because one you don't understand the riding and two you have fixed ideas about how things should be and those clash with what he has designed. If you have any interest in designing something revolutionary you are going to have to ask questions of the real world and not just books.

kitexpert
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Re: Speed 3 21m Upwind adjustment

Postby kitexpert » Sat Jul 30, 2016 12:24 pm

Cloud is far from "something revolutionary" as a kite. Idea of strutless LEI is not new, and Clouds have low A/R and it is not high performance kite. It is however light weight kite and no doubt very useful for wave riding and hydrofoiling (not racing).

In his youtube video Greg explains Cloud history and tells how the process to make it was. He says there was quite a lot copying/studying existing kites and some luck for the first prototypes - nothing wrong here. His remarks are a bit trivial and do not show very deep understanding, though some original thinking is there. No doubt he knows well enough strutless kites, but I don't think he could design good big air/freeride kite or even less high AR foil kite. With these kites simplicity is just not enough.

I see high performance kites the most challenging and ambitious kites there is. Single skins are another type which has development potential, but L/D is difficult to get comparable level to other kite types. Single skins produce high lift however and for example Peaks upwind ability is not bad at all.
foilholio wrote: Two kites that could not be more apart. It is like you have a split mind, interesting.
In high winds I prefer LEIs. I am not foil or LEI "fundamentalist", but I use different kites in different conditions.

foilholio
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Re: Speed 3 21m Upwind adjustment

Postby foilholio » Sat Jul 30, 2016 1:52 pm

AaaaaLLLLaaah kiiiittttebaaaaar.

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Kamikuza
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Re: Speed 3 21m Upwind adjustment

Postby Kamikuza » Sat Jul 30, 2016 3:14 pm

foilholio wrote:AaaaaLLLLaaah kiiiittttebaaaaar.
God hates foils and foil enablers


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