I have just purchased a couple of upmarket wings with separate inflatable leading-edge and strut bladders. My previous wings (Units) were connected and had a definite recommend pressure, eg 7.5psi, but these new wings have a different range for each bladder, eg 7-9psi, printed on them.
What are the characteristics or conditions for using the upper or lower limits on the two bladders?
I had heard lower pressure on leading edge bladder is better for light wind pumping on to foil. but I could be mistaken.
Cheers

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mikey100 said..
I have just purchased a couple of upmarket wings with separate inflatable leading-edge and strut bladders. My previous wings (Units) were connected and had a definite recommend pressure, eg 7.5psi, but these new wings have a different range for each bladder, eg 7-9psi, printed on them.
What are the characteristics or conditions for using the upper or lower limits on the two bladders?
I had heard lower pressure on leading edge bladder is better for light wind pumping on to foil. but I could be mistaken.
Cheers

yes, approximately if you inflate the strut 1PSI less than the max recommended pressure, you gain 5-10% more power (size equivalent). A 5m with strut inflated 1PSI less is roughly a 5.2ish

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SlowlyButSurely said..

mikey100 said..
I have just purchased a couple of upmarket wings with separate inflatable leading-edge and strut bladders. My previous wings (Units) were connected and had a definite recommend pressure, eg 7.5psi, but these new wings have a different range for each bladder, eg 7-9psi, printed on them.
What are the characteristics or conditions for using the upper or lower limits on the two bladders?
I had heard lower pressure on leading edge bladder is better for light wind pumping on to foil. but I could be mistaken.
Cheers

yes, approximately if you inflate the strut 1PSI less than the max recommended pressure, you gain 5-10% more power (size equivalent). A 5m with strut inflated 1PSI less is roughly a 5.2ish

Can you explain why this would be?

I'm not trying to be snarky or anything, I'm just not sure that's a universally true statement and curious why this would be the case.

IMHO Sometimes a floppy wing is worse for getting on foil in light wind.

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Oahuwaterwalker said..

SlowlyButSurely said..

mikey100 said..
I have just purchased a couple of upmarket wings with separate inflatable leading-edge and strut bladders. My previous wings (Units) were connected and had a definite recommend pressure, eg 7.5psi, but these new wings have a different range for each bladder, eg 7-9psi, printed on them.
What are the characteristics or conditions for using the upper or lower limits on the two bladders?
I had heard lower pressure on leading edge bladder is better for light wind pumping on to foil. but I could be mistaken.
Cheers

yes, approximately if you inflate the strut 1PSI less than the max recommended pressure, you gain 5-10% more power (size equivalent). A 5m with strut inflated 1PSI less is roughly a 5.2ish

Can you explain why this would be?

I'm not trying to be snarky or anything, I'm just not sure that's a universally true statement and curious why this would be the case.

IMHO Sometimes a floppy wing is worse for getting on foil in light wind.

particularly for wing with very highly tensioned stitched panels (armstrong XPS for example), lowering strut pressure and removing battens allows the wing to be more "springy" when pumped.

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Oahuwaterwalker said..

SlowlyButSurely said..

mikey100 said..
I have just purchased a couple of upmarket wings with separate inflatable leading-edge and strut bladders. My previous wings (Units) were connected and had a definite recommend pressure, eg 7.5psi, but these new wings have a different range for each bladder, eg 7-9psi, printed on them.
What are the characteristics or conditions for using the upper or lower limits on the two bladders?
I had heard lower pressure on leading edge bladder is better for light wind pumping on to foil. but I could be mistaken.
Cheers

yes, approximately if you inflate the strut 1PSI less than the max recommended pressure, you gain 5-10% more power (size equivalent). A 5m with strut inflated 1PSI less is roughly a 5.2ish

Can you explain why this would be?

I'm not trying to be snarky or anything, I'm just not sure that's a universally true statement and curious why this would be the case.

IMHO Sometimes a floppy wing is worse for getting on foil in light wind.

It's roughly equivalent to loosening the outhaul, you're allowing the leading and trailing edge to move closer, increasing camber of the sail, and also loosening the leach.

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mikey100 said..
I had heard lower pressure on leading edge bladder is better for light wind pumping on to foil. but I could be mistaken.

I actually do the opposite.. I pump my wings up more for light wind (stiffer and better to pump), and less in strong winds to allow it to dump and be softer in strong gusts.. I find my Aluula wings pump so much better than the less stiff leading edge.I can see that less bladder pressure would make wing a deeper sail (like the outhaul/downhaul analogy @Alenh uses), not sure how relevant this is for wing foiling at high apparent wind angles/speed though vs a sailboat that let's these controls out to go downwind or gain a little extra depth/power in very light winds..Keen to hear other thoughts..!