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Rear wing aoa??

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kas911
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Rear wing aoa??

Postby kas911 » Mon Apr 10, 2017 6:38 am

Hello. I have the opportunity to change the angle on my Rear wing. Sroka foil

I feel that the nose of my board rides a little low and would like to raise it if possible. Can i use the Rear wing trim to do that?

Front straps are in the middle. No back strap but foot on top pr a little behind the mast

Kasper

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Peter_Frank
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Re: Rear wing aoa??

Postby Peter_Frank » Mon Apr 10, 2017 7:47 am

kas911 wrote:
Mon Apr 10, 2017 6:38 am
Hello. I have the opportunity to change the angle on my Rear wing. Sroka foil

I feel that the nose of my board rides a little low and would like to raise it if possible. Can i use the Rear wing trim to do that?

Front straps are in the middle. No back strap but foot on top pr a little behind the mast

Kasper

Yes you can :D

You simply decrease the aoa on your rear wing, so it lifts a bit more "down", and your board will not be as "noseheavy" anymore :thumb:

Decreasing aoa means lowering the LE or lifting the TE a bit up.

8) PF

kas911
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Re: Rear wing aoa??

Postby kas911 » Mon Apr 10, 2017 8:09 am

So i "lower" the wing to raise the nose of the board?

Dont know what LE and TE are :-)

Thank you mr windfoiler :-D

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Re: Rear wing aoa??

Postby max » Mon Apr 10, 2017 2:38 pm

kas911 wrote:
Mon Apr 10, 2017 8:09 am
So i "lower" the wing to raise the nose of the board?

Dont know what LE and TE are :-)

Thank you mr windfoiler :-D
LE is the Leading Edge of the wing . . . . the front edge of the rear wing (stabiliser).

TE is trailing edge . . . the rear edge of the stabiliser

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Re: Rear wing aoa??

Postby Mossy 757 » Mon Apr 10, 2017 3:09 pm

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Re: Rear wing aoa??

Postby TomW » Mon Apr 10, 2017 3:36 pm

I'm still a noob, but fascinated and curious about hydrodynamic of foiling.
If one increases AoA on rear wing, I assume I have to shift weight forward on board to maintain altitude? Then front wing is at some other AoA compared to before change?

Isn't OP really looking to just change angle of board to water? Why not tilt strut back on board and keep wing trim the same?

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Re: Rear wing aoa??

Postby Lokihel » Mon Apr 10, 2017 5:44 pm

Changing the stabiliser angle of attack will mostly affect how much front foot pressure is required.

Unless you have a really weird design, the increased downforce from the stabiliser will not cause a noticeable change in main wing angle of attack (to compensate with more lift).


If you want to change the angle of the board relative to the water, you have to change the angle of the board relative to the fuselage.
Like TomW just said: change the angle of the mast relative to the board (or fuselage, whatever is feasible).

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Re: Rear wing aoa??

Postby Mossy 757 » Mon Apr 10, 2017 7:19 pm

You're just changing the L/D of the stab by adjusting AoA...this affects front foot pressure, but ultimately the front wing still wants to travel at the "right" AoA in the water.

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Re: Rear wing aoa??

Postby Cdog » Mon Apr 10, 2017 9:06 pm

See if you can move your strut once its bolted in
You may have to shim the strut head
You can try soda can and cut some shims out of that

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Re: Rear wing aoa??

Postby TomW » Mon Apr 10, 2017 9:35 pm

Then my intuition was correct! Don't have any formal knowledge, but know how an airplane works. If OP has a strut plate he can shim that.


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