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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Fri Nov 29, 2013 8:30 pm 
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Hawaiis wrote:
Ronnie:
Thanks
GoPro3 has an App that one can use iPhone to preview from the camera with WiFi, when I put camera in the water, the wifi signal is lost. Since there is ocean current, the fins have been moved from where I lost it.


I was expecting you to look at the film on a computer after completing the grid. You should be able to detect where the foil was from the time on the film.
If you had a waterproof gps you could film it at the end of each straight run of the grid. Otherwise you could film two lineups on the shore at the end of each line.

You could have 2 balloons to anchor one at the start of each layline, then aim maybe 40' down-current of the other balloon. Then at the end of each run, move the nearest balloon 80' down-current.
If you know which direction the foil would be taken by the current, you could start before the likely drop point and gradually lengthen the distance between the bouys every time you move the layline in the direction of the current.


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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Fri Nov 29, 2013 10:31 pm 
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I found this interesting.

http://www.diy-wood-boat.com/Glue.html


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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Mon Dec 02, 2013 9:49 am 
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don pitcher wrote:

Thank you Don, here is the completed all wood Twin Tip bidirectional hydrofoil, I epoxy the joint, so the fuselage and strut is one piece, even if it break off again, it will float.


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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Mon Dec 02, 2013 2:05 pm 
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Location: Chile/Brasil
This weekend i got to almost finish the fuselaje.
Made some mistakes but this is what it looks like.
The kell i will prepare durung this week.
A couple of more weekends and it will be done.
Fuselage is 730mm long 30mm thick and thichest height is 70mm where the the keel will be inserted.
i used 4 layers of 6 oz.fiberglass in the middle of fuselaje to bond and increase rigidity.
Tail section looks like a katana sword. an is triangular in shape.
see you guys next week,
have a good day!! :thumb:


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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Mon Dec 02, 2013 7:16 pm 
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Looks great! Can't wait to see what you guys learn from these prototypes.

This is the best thread in Kiteforum.


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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Tue Dec 03, 2013 9:42 am 
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Location: Tauranga, New Zealand
Hawaiis wrote:
Wood is naturally buoyant, it helps lift the board off the water, resulting in higher light wind performance.


Buoyancy = ρgV - determined by volume, the force upwards (assuming buoyancy force is greater than weight) would be completely insignificant compared to the gains for light wind that a smaller, higher AR high lift profile would provide.


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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Tue Dec 03, 2013 10:16 am 
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Bradn wrote:
Hawaiis wrote:
Wood is naturally buoyant, it helps lift the board off the water, resulting in higher light wind performance.


Buoyancy = ρgV - determined by volume, the force upwards (assuming buoyancy force is greater than weight) would be completely insignificant compared to the gains for light wind that a smaller, higher AR high lift profile would provide.

Assume the average weight of a typical metal or composite foil is 10 lbs, you need to lift the 10 lbs off the water in addition to your body weight. A 10lb wood foil if at .33 density will lift you up with 20 lbs, so the total gain or weight loss is 30 lbs


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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Tue Dec 03, 2013 3:52 pm 
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mmm, mmmmm.
I think that overestimates the buoyancy.
take koa wood for example
typical density is 42 lbs/ft^3, or 0.62 X seawater (42lbs/ft^3 / 63.xx lbs/ft3 = 0.63)
say there are 10lbs of it, that must be 0.238 ft^3 (10lbs / 42lbs/ft^3 = 0.238 ft^3)
The buoyancy force comes from the water displaced by the 0.238ft^3 of wood.
0.238ft^3 of water weighs about 15 pounds (0.238 X 63 = 15).
While the wood weighs 10 pounds.
The buoyancy force is the difference betweeen the wood's weight and the weight of water the wood displaces, 5 lbs.
I think that is the answer.... :idea:


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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Tue Dec 03, 2013 5:54 pm 
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BWD wrote:
mmm, mmmmm.
I think that overestimates the buoyancy.
take koa wood for example
typical density is 42 lbs/ft^3, or 0.62 X seawater (42lbs/ft^3 / 63.xx lbs/ft3 = 0.63)
say there are 10lbs of it, that must be 0.238 ft^3 (10lbs / 42lbs/ft^3 = 0.238 ft^3)
The buoyancy force comes from the water displaced by the 0.238ft^3 of wood.
0.238ft^3 of water weighs about 15 pounds (0.238 X 63 = 15).
While the wood weighs 10 pounds.
The buoyancy force is the difference betweeen the wood's weight and the weight of water the wood displaces, 5 lbs.
I think that is the answer.... :idea:

I just used the density of bamboo as example at .33
The paulownia wood has density of .2 and koa wood has density of .6


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 Post subject: Re: DIY Home Made wooden Hydrofoil fins
PostPosted: Tue Dec 03, 2013 11:14 pm 
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Joined: Wed Nov 20, 2002 1:00 am
Posts: 878
Location: rhode island
BWD wrote:
mmm, mmmmm.
I think that overestimates the buoyancy.
take koa wood for example
typical density is 42 lbs/ft^3, or 0.62 X seawater (42lbs/ft^3 / 63.xx lbs/ft3 = 0.63)
say there are 10lbs of it, that must be 0.238 ft^3 (10lbs / 42lbs/ft^3 = 0.238 ft^3)
The buoyancy force comes from the water displaced by the 0.238ft^3 of wood.
0.238ft^3 of water weighs about 15 pounds (0.238 X 63 = 15).
While the wood weighs 10 pounds.
The buoyancy force is the difference betweeen the wood's weight and the weight of water the wood displaces, 5 lbs.
I think that is the answer.... :idea:


:)
let it go.
...the kid's on a roll


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