I have the same two wings.cglazier wrote:Thanks Peter for a very good explanation. It matches my experience.
I have two wings for my Spotz foil, one with low AR and one with a high AR. The low AR one works well and is forgiving and it starts at low board speeds. The high AR one does not feel too much different at first but then I noticed that it stops foiling at very low speeds. It is also allows me to reach higher maximum board speeds. When it stops foiling it is very abrupt. All this is consistent with your explanation.
Everyone I talk to who has a Spotz foil seem to use the high AR wing mostly. As you gain more experience you learn to maintain higher board speeds and you stall less often. I expect that as the typical foil rider gets more skilled we will see the higher AR wings more commonly. I remember the very early days of kiteboarding when very low aspect kites were common because everyone was a beginner, but now higher aspect kites are the norm.
The amount of lift from the foil depends on the rider weight and line tension (force equilibrium), which should not be variables of AR. Therefore drag is inversely proportional to L/D ratio and maximum L/D ratio is therefore desired for high speed, which (as you know) means a high AR foil. Naturally, the wing itself should be smaller for high speeds, but that is another discussion unrelated to AR.A fast wing is a high AR wing, right ?
interesting, as in theory a high AR wing is more ´lift sensible´ to AOA changes than a low AR wing, i.e., (simplifying) a small change in AOA leads to a big change on lift for a high AR wing, not so much for a low ARChristoffM wrote:Well explained Peter. The only part that I would disagree with is that beginner wings should be low aspect ratio. I am starting to find that the increased stability of a high aspect ratio wing far outweights the benefits of having a lower aspect ratio wing. The lower aspect ratio wing is simply easier to manufacture (it needs less stiffness/strength).
was expecting things to be set-up in a way that under a stall there was an "automatic" pitchChristoffM wrote: I find that my high aspect ratio wings do not stall badly at all, and if they do stall I simply recover by tilting the nose of the board down.
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