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Re: DIY Home Made wooden Hydrofoil fins

Posted: Wed Nov 13, 2013 9:27 pm
by Europ2
Mini Tuttle box blueprints are difficult to find.
NSP mini tuttle fin boxes are around 9cm long x 1.8 cm high x 1.3cm wide

If somebody has the blueprints+ dimensions, pls post here.
http://www.windsurfingfins.co.uk/prod5. ... rod_anchor

The Mini-Tuttle foilboard struts plug can be casted in one of the mini tuttle boxes as described bellow.

Here is my favorite link from Reystos.about Tuttle box.
http://www.geocities.ws/reystos/fin_making/index.htmll

(From the legendary http://www.geocities.ws/reystos/ :jump: and his SW for designing kites - some 12 years ago)
Although I cannot guarantee the results of this method, you can use a finbox to cast the base. This applies to Powerbox and Tuttle (+Deep Tuttle) fins. Trimbox fins can't be cast in their box as the box doesn't have the fin's shape. Make sure your finbox is waxed well and the screw holes are sealed with plasticine before casting with thickened resin or epoxy putty. You will also have to figure out a way to keep your fin vertical in respect to the level of the finbox. Another detail you will need to figure out is how to place the screw nuts in position, since casting with the screws in place is no easy task.
Image

Fin designer still available here: http://www.geocities.ws/reystos/fin_designer/index.html
I cannot open the Zip archive (old Win 95/98/ME Zip version not compatible xith Win VISTA, 7 Zip ? 32bit vs 64bit ??)

For our 100 or 110 mm chords, the 160mm box will clearly be over dimensionned.

3G composites (Ketos by Orana) have developped their own box based on morse cone sections around 5 degrees (versus 6 for the tuttle box wall).
AlpineFoil use this setup on the 5.0 board version with the Courtesy of 3G composites.

Re: DIY Home Made wooden Hydrofoil fins

Posted: Wed Nov 13, 2013 11:13 pm
by Johnny Rotten
Although I cannot guarantee the results of this method, you can use a finbox to cast the base. This applies to Powerbox and Tuttle (+Deep Tuttle) fins. Trimbox fins can't be cast in their box as the box doesn't have the fin's shape. Make sure your finbox is waxed well and the screw holes are sealed with plasticine before casting with thickened resin or epoxy putty. You will also have to figure out a way to keep your fin vertical in respect to the level of the finbox. Another detail you will need to figure out is how to place the screw nuts in position, since casting with the screws in place is no easy task.
This works well.
http://kiteracing.com/Pot_a_Fin.html
If you look into the background of some of the rista fins videos you can see a similar jig so I suspect this is (sorta) how the pros do it.

I would recommend adding a second nut onto the bolt you put in. so that is fully encased. in the epoxy and cannot pull out.

Epoxy/milled glass powder can work as a casting agent, if you don't have a urethane kicking around. I also recommend locktite frekote as a mold release, If you can't get the crap these guys are using wax doesn't work well on the best of days and is miserable to apply to the inside of a fin box.

Re: DIY Home Made wooden Hydrofoil fins

Posted: Wed Nov 13, 2013 11:29 pm
by Hawaiis
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

Re: DIY Home Made wooden Hydrofoil fins

Posted: Wed Nov 13, 2013 11:46 pm
by ozchrisb
Hawaiis wrote: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.

Re: DIY Home Made wooden Hydrofoil fins

Posted: Thu Nov 14, 2013 1:01 am
by Hawaiis
ozchrisb wrote:
Hawaiis wrote: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

Re: DIY Home Made wooden Hydrofoil fins

Posted: Thu Nov 14, 2013 3:02 am
by don pitcher
Hawaiis wrote:the weight of the whole bottom unit is 2.55 kg
Compared to

MHL 3.7 kg
Carafino 4.35 kg
Rush Randle 5.5kg
MyWood 2.55 kg

Wow! A Carafino is that close in weight to a Rush Randle. While the MHL has much flex.

There really is a place for a low cost hydrofoil made of aluminum. Just have to find a source for a riser that is made of a hollow extrusion in a NACA shape.

Re: DIY Home Made wooden Hydrofoil fins

Posted: Thu Nov 14, 2013 3:30 am
by Hawaiis
Sorry, my Private Message box does not allow me to reply, it only let me post it to the outbox and stayed there.

Stan:

You should check out my older posts, most of the information are listed, my research is still ongoing, when i finally finish the project, I will post the details on how to make one.
Sent: Wed Nov 13, 2013 5:24 pm
View message Reply with quote

oldkiter
Message subject: Your foil boardFolder: Inbox
I showed your video on your homemade foil board to a friend and he wants to make one for himself - he was very impressed. Can you provide some more specific info other than that on your description with the video.

Thanks,

Stan

Re: DIY Home Made wooden Hydrofoil fins

Posted: Fri Nov 15, 2013 9:15 pm
by zfennell
don pitcher wrote:
Hawaiis wrote:the weight of the whole bottom unit is 2.55 kg
Compared to

MHL 3.7 kg
Carafino 4.35 kg
Rush Randle 5.5kg
MyWood 2.55 kg

Wow! A Carafino is that close in weight to a Rush Randle. While the MHL has much flex.

There really is a place for a low cost hydrofoil made of aluminum. Just have to find a source for a riser that is made of a hollow extrusion in a NACA shape.
Don,
if you were to find a hollow aluminum strut with overall dimensions
-chord lenth: 4 in
-profile thickness: .59in (15mm)
-wall thickness: .1 in
-span length: 39 in

the foil would closely match the stuffness numbers provided by Europ2 in his thread.
weight of strut would be approx 2.7 lbs

personally, i doubt the foil needs to have any specific profile.
naca, ellipse, circular arcs... as long as it's streamlined.
i wonder how much laterall lift (from the strut) the rider could actually tolerate while standing on top of the entire mess. ( i'm guessing that its not much)
i'd certainly like to hear from folks that know better.
-bill

Re: DIY Home Made wooden Hydrofoil fins

Posted: Fri Nov 15, 2013 10:35 pm
by don pitcher
zfennell wrote: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.

Image

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.

Image

Re: DIY Home Made wooden Hydrofoil fins

Posted: Fri Nov 15, 2013 11:30 pm
by zfennell
don,
just for comparisons:
if you use a measurement system like Europ2...

the 3" x 9/16" x 1/16" strut from bcawning will flex 2" :::::correction: 3/4 in

if you increase the wall thickness to .1", flex will reduce to 1-1/4" :::corrrection: 1/2in

a similar shape that's 4" x 9/16" x .1" will flex only 1/2"
this is similar to the numbers from Europ2 measurements.

certainly not the answer, just relative differences.
-bill