Forums > Stand Up Paddle Foiling

Rear wing up or down?

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Created by stevet73 8 months ago, 20 Oct 2018
stevet73
NSW, 137 posts
20 Oct 2018 7:50AM
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I picked up a used 'china rip off' all carbon surf foil (based on the lift foil template) just for pure curiosity to play around on a prone board-have sup foiling down. The rear wing fits seamlessly facing down but I had always assumed the rear wing goes up - which I did manage to fit it facing up with some new screws...although not quite as neat alignment.

80% of the pics I looked at online has the front wing down/rear wing up BUT there was a couple with the rear wing down.

Any thoughts?





DavidJohn
VIC, 16139 posts
20 Oct 2018 8:34AM
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Nice rug..

stevet73
NSW, 137 posts
20 Oct 2018 11:02AM
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Select to expand quote
DavidJohn said..
Nice rug..


Ha! Yes. It does have that 'keys in the bowl/swingers club's vibe.

Suits the man shed well.....

RAL INN
VIC, 2727 posts
20 Oct 2018 11:22AM
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Whichever way means the rear wing pushes down.

Gorgo
VIC, 4195 posts
20 Oct 2018 11:58AM
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Try it and see. If you can't tell then it doesn't matter.

warwickl
NSW, 1158 posts
20 Oct 2018 3:48PM
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I have Naish foils and stab is tip down.
I did try it tips up to minimize contact with the bottom but was a no go so tips down for Naish SUP foils.
Some are up and some are down.

tightlines
WA, 3158 posts
20 Oct 2018 3:22PM
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If it fits seamlessly with tips down then that is probably the way it is designed to go.

Heaps of foils do.

stevet73
NSW, 137 posts
20 Oct 2018 7:10PM
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Thanks folks....so maybe it is rear wing down after all. As it's a lift foil 'rip off', I checked the lift foil profile and their rear wing is definitely up.....but if u guyscare calling wings down is really not that strange then I'll indeed run it both ways.

Anyone savvy with the 'rear wings up vs. down' hydrodynamics? Or is it really like a box of chocolates..to use forest gump analogy...

DWF
87 posts
20 Oct 2018 5:59PM
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Put a level on the rear wing. Figure out which way it's creating lift downward. Then you got it right.

warwickl
NSW, 1158 posts
20 Oct 2018 8:46PM
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1mm aoa makes a huge difference.
The test is where you need to put your back leg for lift off and comfort on the fly.
If to far one way or the other for your comfort stance then adjust aoa.
Works for me.

stevet73
NSW, 137 posts
21 Oct 2018 2:09PM
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Select to expand quote
foilSURFmachines said..
Put a level on the rear wing. Figure out which way it's creating lift downward. Then you got it right.


Thanks fSm for that suggestion. I may be a bit special but Im not sure what you mean....
Select to expand quote
warwickl said..
1mm aoa makes a huge difference.
The test is where you need to put your back leg for lift off and comfort on the fly.
If to far one way or the other for your comfort stance then adjust aoa.
Works for me.


And thanks warwickl. What does the "aoa" acronym mean? Also, back foot usually doesn't move - once up? Im not sure what you mean....again, I may be a bit special....

stevet73
NSW, 137 posts
21 Oct 2018 2:12PM
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The more I think about it twists my mind that you can have foils with rear wing up and some with rear wing down....fair enough there are some that are flat....but complete opposite?

Not seen any airplanes with a rear wing down as yet......is there a hydrodynamic nerd in the house? That can pitch at dummy level....

Fishdude
51 posts
21 Oct 2018 3:58PM
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The rear stab on a foil should have some small amount of angle to it that makes it want to move downward When travelling through the water. This in turn makes the front wing want to go upward. (A upward AOA... angle of attack)

So do like FoilSupMachine says it should help you find the correct way for your foil.

AOA angle of attack. You might want to look this up...

stevet73
NSW, 137 posts
21 Oct 2018 7:02PM
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Thanks fishdude. So, if I'm understanding correctly, a rear wing must create a downward force to cause the opposite effect at the front wing..ie lift. The rear wing therefore can be facing up or down/mounted top or bottom BUT it's design will vary to create that same 'downward' force....

And angle of attack refers to the foil in relation to the wave angle/flow of water....I think....

toppleover
QLD, 1504 posts
21 Oct 2018 7:22PM
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90% of the foils I have seen have the rear stabilizer wing pointing down.

stevet73
NSW, 137 posts
21 Oct 2018 7:39PM
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2018 foils seemed to be majority rear wing up.....now 2019 is looking rear wing down....fair call?



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"Rear wing up or down?" started by stevet73