On 2002-12-14 20:03, Mr Jo Macdonald wrote:
If you compare a monster medium/low Ar foil flying in less than 10 knots to a 16m high Ar Lei flying in 15 the lei will win hands down but if you compare a 12m foil to a 16m lei in the same wind is there that much difference?
On the question of sining, does a foil produce more pull while it turns because it flies through the turn instead of spining? If the lei turns faster because it stops and spins whiel the foil flies though the turn the lei will lose a lot more apparent wind.
Thinking about it logically as the foil is flat there's a lot more of it to turn that a C shaped LEi but I have definately been in situations where a foil was flying and turning so fast and producing so much power I was trying to slow it down and others with LEis where things were very slow.
Like I said before I think it depends a lot on the wind conditions.
Last question, if LEis turn faster then foils how come all the stunt kites are foils and not inflatable Cs?
The small kites is a totally different matter, so here I will not compare.
The main object of small kitesurfing kites is to slow the turning down - because you need the kites to turn very alike and useable for most kitesurfers and kitesurfing tricks.
And regarding stunt kites - here we are down in totally different angles and circumstances.
A very small foil is excellent, as turning on short lines (compared to the kite size) is not a problem, and you just want THE most low drag fast kite possible.
Here you don't need to brake the foil TE, to turn - making these even faster (2 lines are often fast enough).
No one would like a stunt kite for kitesurfing - turns way too fast.
Only if you are a land kite flyer, you might find some fascinating challenges in this I think.
Foils and LEI both "Fly" through the turn - the LEI does not stop and spin around, on the contrary - you are to some extent using the sides as a rudder also, instead of slowing the kite down by pulling a trailing edge in one side.
And even if the LEI slows down and turns (or you make it do so..) - it will lift better because of more power at low speeds !
And as you correctly stated - the C shape is easier to turn, than a flat kite - even if the C kite has to be bigger in area.
This is why you can't use a paraglider in light wind (only parked - and who cares about that.. No fun) - the turning capabilites would be awful, because of the high AR and inefficient lift distribution for turning fast.
Why do you "power up" your LEI when turning Jo ? No reason for this, just let it be powered as you wish, and steer the kite around. In fact one will often depower the whole kite during the turn, as it will travel even faster(speed) around, giving more speed and lift (almost no brake effect).
This is the very idea of the newer LEI's - you can turn quite sharp, without braking/slowing down too much.
And IF you slow it down, it'll still lift okay because of its sheer area size.
You can tweak the kite around a lot, and keep a more constant pull. Thats why a lot of wakeboarders prefer lower AR, and short lines often.
But you are right Jo - the things we talk about regarding turning, are most evident on the bigger sizes.
With small kitesurfing kites, one should choose foil or LEI after other guidelines than turning.
If one compares a 16m2 LEI to a 12m2 Foil - they could be very alike regarding turning.
But if you take the ultimative light wind kites of both (18m2 LEI, North f.ex) - then you will see the difference.
The foil has better parked low end capabilities - but because of the lack of fast turning without speed loss, it does not work for other than cruising, or small jumps straight up (which can be the thing you want of course).
I am trying to explain why LEI's have such a major part of the market, almost all of it - also if you look purely at performance, and not practical reasons.
If foils turned faster effectively, jumped higher, and had more power - then there would for sure be some who would use these (and these only) to win the contests (and win much easier) !
Maybe it will come in the future, no-one knows...
But it is not like this today.
Apart from all this - I still find foils much more fun and interesting to fly !!! (but LEI's better suited for kitesurfing generally)
Kindly - Peter Frank
<font size=-1>[ This Message was edited by: Peter_Frank on 2002-12-14 21:16 ]</font>