DIY Home Made wooden Hydrofoil fins

[ozchrisb]

The Tuttle box used by raceboards should work, I just can not find them in the States for sale.
Anyone knows where to buy them?

Mahalo

EDIT: found the cheaper one further down the page
Yes I have one at home I bought from:
http://www.fiberglasssupply.com/Product ... #Sailboard
Get the plastic one
R54-4561
Chinook "Tuttle" Plastic Race Box, Chinook (#305)
$16.26

They have all kinds of other box and glassing supplies too.

do you have the dimensions ? There seem to be none on the internet even on Chinook's own website.

Mahalo

Do you want the dimensions of the outside of the box? I bought this because I couldn't accurately measure the inside of a box on my boards, so I can't get you the internal dimensions. The image that's attached above in on a few websites and a couple mention that it's wrong. Nobody seem to be able to get them exactly the same. Sanding fins/foils to fit boxes on race boards is standard practice.

[Hawaiis]

Is it even close to these dimensions?

[Hawaiis]

personally, i doubt the foil needs to have any specific profile.
naca, ellipse, circular arcs... as long as it's streamlined.

That is what I was thinking. I have been tempted by the aluminum extrusion below. But, I wish there was more wall thickness.



http://www.bcawnings.com/?o=modules&n=a ... idinfo=899




I want to get rid of my frame and add a streamlined riser. I might have to give the extrusion above a try.

How does your twintip hydrofoil work?
Any videos?

Mahalo

[don pitcher]

Sorry, no video.

I knew it would not be near as efficient as a directional; but, it is not as efficient as I would like. It needs to get better and I think it has potential.

I found having the two wings separated like they are causes the front wing (front depends on which direction I am traveling) to have more lift than the rear wing because the "wake" of the front wing disturbs the flow over the rear wing. This requires much front foot pressure to maintain level.

I then moved the wings together. This was better, but pitch control needs to be improved. I have been too busy to progress this further.

My next step would be:

*remove the draggy frame with a streamlined riser.

*to have one wing in the middle and two small stabilizer wings at the end.

*use a long square tube as the fuselage to move the stabilizer wings further away from the center wing. This will allow for a smaller stabilizer wing which will have less disruption of flow to the middle wing.

With the extrusion i mentioned previously, this could all bolt together. It doesn't get any easier than that!

Some day I will have time to progress this further.

Better yet... Why not have one of you single folk progress this idea for the rest of us? You got the time and the cost is not much. The whole set-up in the picture that I posted only cost $200 and that includes the $25 wakeboard that I bought on Craigslist.

[Bille]

personally, i doubt the foil needs to have any specific profile.
naca, ellipse, circular arcs... as long as it's streamlined.

That is what I was thinking. I have been tempted by the aluminum extrusion below. But, I wish there was more wall thickness.



http://www.bcawnings.com/?o=modules&n=a ... idinfo=899

...

Mahalo

OK -- you want Thicker ; then add some composites to the out-side
of that extrusion.

One thing though --
It's already at 18.75 % thickness of cord, so adding anything more
just makes it worst for drag ; 12% is more where it Should be !!

Bille

[don pitcher]

My goal is a low cost design that is easy to mass produce. This is why I like aluminum. Because of this goal and the mess of composite resins, I am not interested in composites for my project.

I think it would be good for the sport if someone offered a low cost, entry level, hydrofoil that could be easily bolted to a cheap used board. IMO, the cost of entry into a hydrofoil is unreasonable.

I like this wood concept.

[Bille]

..

I like this wood concept.

Sometimes it takes some convincing, but
--Hawaiis--, convinced me that wood is Definitely the way to go for my
first hydrofoil ; aluminum is TO0oo Heavy, and it Hurts when it Hits
you, and like you say, composites Are messy

Ultimately, if your goal is to build a Cheap alternative to the expensive
ones now available, then Wood combined with just a touch of composites
will probably end up being the way to go.
Things made from Wood are Cheap to produce, lighter than aluminum,
and with less than 1/2 the mass of metal , (even when covered with fiberglass),
there's less odds that one of your customers will die , ((if that thing hits them in the head)).

Say what you want about the guy, but i SEE WHY he posted this below
and it's coming from a person that Already mass-produced a foil made
from metal ; Ya think he might have Learned something from his endeavours?

from Titanium Foil :

Metal kills people, no matter how light you can make it. No matter how fast it will go. Metal is out.
Plus the cost for titanium is horrendous. keep up the good work.

Bille

[longwhitecloud]

i using aluminium extrusion like that - gonna wrap upright in carbon tho i think as it is set up on board now and a bit flexy..- it is ready to try without tho - we c . tried 15mm ply wings i shaped on another t bar, well my friend did - said they worked ok but a bit draggy - cost $3 and took 20 mins to shape.

what else can u use that is super cheap and real stiff? how about the aluminum profile for foils.. would work i would guess, just add angle of attack...

[Laughingman]

My goal is a low cost design that is easy to mass produce. This is why I like aluminum. Because of this goal and the mess of composite resins, I am not interested in composites for my project.

I think it would be good for the sport if someone offered a low cost, entry level, hydrofoil that could be easily bolted to a cheap used board. IMO, the cost of entry into a hydrofoil is unreasonable.

I like this wood concept.

It's already been done. $900 for board and foil. Adjustments are likely required...

http://skyski.com/store/all-new-hydrofl ... ofoil.html

[don pitcher]

longwhitecloud,

1/8" 7075-T6 aluminum plate will work as a wing.



Billie,

If using aluminum extrusions, an aluminum hydrofoil can be about the same weight as a Carafino. Also, the concern about aluminum not being safe is not true. The ski boat world has been using aluminum hydrofoils for years.



Laughingman,

While $900 is much less than a carbon foil, I still think that price is too much. If using aluminum extrusions, I would expect a manufacturer could sell a bolt-on hydrofoil kit for about half of the Sky Ski price and still have enough profit to make it worth doing.

Also, the Sky Ski design does not mount to the board in a way that would be useful for kite surfing.