Contact   Imprint   Advertising   Guidelines

Change AoA of front wing

Forum for hydrofoil builders.


User avatar
kjorn
Very Frequent Poster
Posts: 672
Joined: Tue Feb 11, 2003 10:42 am
Kiting since: 0
Brand Affiliation: None
Location: uk
Contact:

Change AoA of front wing

Postby kjorn » Wed May 23, 2018 1:20 am

Hi, got a quick question.

Made my own hydrofoil a couple of years ago. I put zero degrees of angle of attack on the front wing.

When I ride the board I need to point it way up into the sky to get lift off. I am now mid process of making a better board, so while I'm at it I want to change the AoA of the front wing. I have two choices:

1. Make a 5 degree wedge between the front wing and the mast.
2. Make a 5 degree wedge between the foil and the board.

I am leaning towards option 2. Tilt the whole thing. Any opinions?

User avatar
foam-n-fibre
Frequent Poster
Posts: 430
Joined: Tue Jan 02, 2007 11:50 pm
Kiting since: 2000
Gear: DIY boards and OR kites
Brand Affiliation: None
Location: Ottawa, Canada

Re: Change AoA of front wing

Postby foam-n-fibre » Wed May 23, 2018 12:01 pm

If you tilt the mast you will end up changing the AoA of both wings. I don't know if that is a good thing or a bad thing with your setup. It seems if things are working properly then you will have to change the AoA of both so that they are still the same.

Is it possible that you are having to keep your weight shifted back to keep it flying, especially at lower speeds? If so, what about increasing the AoA of just the rear wing, moving the mast back or the foot position forward more, and using your weight to level it off? Is it hard to keep flying at a smooth height? If so more rear wing angle with the mast moved back should improve its flight. it did for me!

I would not expect the problem you describe if the front wing is currently parallel with the bottom of the board and if you have a few degrees of rear wing angle. But I'm sure there must be some gurus who have played with this more than I have on the one foil I have built.

Peter

User avatar
foilonfoil
Very Frequent Poster
Posts: 579
Joined: Thu Mar 19, 2015 8:31 am
Kiting since: 2013
Local Beach: Belmont Shore, CA / Hood River, OR
Favorite Beaches: Crissy Field, San Francisco, CA / Benicia, CA / Sail Bay, San Diego, CA / Hermosa Beach, CA
Style: Kitefoil
Gear: Flysurfer Sonic Race, Core Section V1's, MikesLab Foil, Camet Boards.
Brand Affiliation: None

Re: Change AoA of front wing

Postby foilonfoil » Wed May 23, 2018 7:23 pm

AlpineFoil include 8 shims with various angles - 4 each for the front and rear wings to fine tune. Think about doing both.

BWD
Very Frequent Poster
Posts: 3403
Joined: Thu Jun 05, 2003 3:37 am

Re: Change AoA of front wing

Postby BWD » Wed May 23, 2018 8:35 pm

first ride it with the new board, see how it goes, try moving it on the tracks if you have tracks.
To tune the foil itself, shimming the rear wing seems the easiest way to try to change something and less likely to affect everything else.
Shimming the front wing affects the board, fuse and tail trim more directly, so it could affect stability and drag more. This could be good or bad!
If you want to shim the mast base on the board also, why not? It affects more variables, so you may not be able to know WHY it causes what it does as easily, but it's easy to add or remove a shim.
Just change one thing at a time, and make thin shims so the change is only 1-1.5 deg at a time.

User avatar
kjorn
Very Frequent Poster
Posts: 672
Joined: Tue Feb 11, 2003 10:42 am
Kiting since: 0
Brand Affiliation: None
Location: uk
Contact:

Re: Change AoA of front wing

Postby kjorn » Thu May 24, 2018 12:36 am

OK will try all of those suggestions.

The only issue with shimming the wings is that the holes through them are so tight that the shim changes the angle of the bolts so I'll need to re-drill the holes to widen them a tiny amount.

lightandfrost
Rare Poster
Posts: 26
Joined: Thu Jul 13, 2017 1:48 am
Kiting since: 0
Local Beach: e
Favorite Beaches: e
Style: onshore waveriding
Gear: v
Brand Affiliation: None

Re: Change AoA of front wing

Postby lightandfrost » Thu May 24, 2018 12:53 pm

Suggest you first refer to the following.

https://www.youtube.com/watch?v=mVdSx5eNdUA

Light and Frost has installed 10 different wing fuselage sets to 5 different masts both curved and straight and approx 8 different board types from old twintips to surfboards up to seven foot. In every case the system had to be tuned as all our equipment is hand made.

In all cases our problems were solved by adjusting the fuselage angle on the mast and/or adjusting the stabilizer angle. AS the video will show, the center of gravity(CG) is 90 degrees to the fuselage. We keep our front wing AOA parrallel to the fuselage.

Please let us what you find when you adjust the front wing AOA if that is the solution you eventually choose to explore.


Return to “Hydrofoil Builders”

Who is online

Users browsing this forum: No registered users and 2 guests

cron