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ittiandro
Joined: 22 Nov 2009 Posts: 294
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Posted: Mon Mar 05, 2018 4:51 pm Post subject: |
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d0uglass wrote: | Francone- My impression is that foils must have a fuselage with both a large front wing and a smaller rear wing to sustain stable flight. I also think that the vertical mast must be fairly long to avoid the board slapping the tops of the waves or the hydrofoil wings breaking the water's surface, although I notice that Slingshot offers a "training" mast that is only 40 cm long. |
Yes, this is what I thought, too, at first, but then I read somebody saying that the smaller rear wing ( and the fuselage) is only for stability when the board rides high on the water, 70 or 80 cm. above the surface. Maybe when you plane or just skim a few inches above the water there is less of a stability issue, just as when you plane on a regular fin...
You are right in saying that the vertical must must be long enough to avoid the board slapping the waves, but I don't foresee riding on 70 or 80 cm high waves I'd rather stay home! Anyway, It won't happen here, because we are not on the ocean, just a lake, mostly flat or with small chop.
Once I get enough feed-back about dimensions, shape, etc, I'll make a marine plywood prototype. If it works, I'll keep it. I'll post the results in the Forum.
Thanks
Ittiandro |
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U2U2U2
Joined: 06 Jul 2001 Posts: 5467 Location: Shipsterns Bluff, Tasmania. Colorado
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Posted: Mon Mar 05, 2018 4:52 pm Post subject: Re: DIY Hydrofoil wing |
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ittiandro wrote: | I have a Bic Windsup and I am planning to make a “ back to the basics’’ DIY hydrofoil ( or..quasi-hydrofoil!)
I have seen people DIY’ing in various clever ways, like joining two fins back to back or even cutting the wing out of a sheet of marine plywood and then sanding one face crosswise from leading edge to trailing edge , to taper it down , like the cross-section of an airplane wing .
Whichever way I make it, my bar is low: I only want to have the board lift off the water in light winds , enough to skim or plane probably 10-20 cm above at most. I wouldn’t go into those elaborate two-wings contraptions flying 1 mt above the water . Too complicated and expensive, for my needs.
I would just attach the wing to the end of a 34-38 cm fin. I can’t use longer fins because the water is very shallow here and the fin box is a US box. I weigh 85 kg.
I wonder if anybody has done something similar and can comment on this, particularly about the ideal wingspan and the width .
The board in the fin box area is about 55 cm wide. The fin box is US. box.
1.Can I assume that the wider the wing surface (wingspan and width) the better the lift.
I am not an engineer, but I know that the drag can be an issue . So may be the drag perhaps poses a limit to the shape and the dimensions ( wingspan and width) should in proportion or respect a correlation..
2. Does it make a difference whether the winglets on each side point up or down ?
3. In some of the photos, there are short 90 degr. downward protrusions at the tips of the wing or in some cases the tips are curled up. Essential or quasi-esthetic variations on the same ...Bach fugue?
Thanks
Francone |
_________________ K4 fins
4Boards....May the fours be with you
http://www.k4fins.com/fins.html
http://4boards.co.uk/ |
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grantmac017
Joined: 04 Aug 2016 Posts: 946
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Posted: Mon Mar 05, 2018 9:59 pm Post subject: |
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Good way to learn how to replace a fin box, but never going to fly even one cm. |
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jingebritsen
Joined: 21 Aug 2002 Posts: 3371
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Posted: Tue Mar 06, 2018 5:37 am Post subject: |
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windSUP 8'11" exocet may be exactly what you want james
you are welcome to come up to central florida and demo mine.
since you are an accomplished SUP rider, i suspect 72 cm will not be too challenging for SUP alone for you.
BTW, i have yet to foil with it, as my business and wave sailing have demanded all of my time. let me know when, so i can get steve to loan us a foil. _________________ www.aerotechsails.com
www.exocet-original.com
www.iwindsurf.com
http://www.epicgearusa.com/ |
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d0uglass
Joined: 28 May 2004 Posts: 1286 Location: Bonita Springs, Florida
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Posted: Tue Mar 06, 2018 11:19 am Post subject: |
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Hey John I- I definitely want to come up and demo your windSUP 8'11" sometime. There will be some sup races in the Melbourne / Cocoa area that will get me up there sooner or later.
I'm not in a huge hurry because at the moment I have less than zero money to spend. I think it's related to being married. Seems like my vehicles, dog, and spouse are always breaking down and requiring expensive maintenance. _________________ James' Blog: Windsurfing Equipment Size Calculator
http://jimbodouglass.blogspot.com/2010/11/updated-windsurf-calculator-online.html |
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joethewindsufa
Joined: 10 Oct 2010 Posts: 1190 Location: Montréal
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Posted: Wed Mar 07, 2018 6:04 am Post subject: |
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you know what they say ...
when vehicle, dog and spouse get to be too much for ya
get rid of the spouse |
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brynkaufman2
Joined: 10 Sep 2002 Posts: 383 Location: Kailua Oahu
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Posted: Wed Mar 07, 2018 11:24 pm Post subject: |
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I do not recommend the GoFoil for wind foiling.
I started with the NP Aluminum, then went to the GoFoil Maliko, and now am very satisfied with the Naish Thrust WS.
The GoFoil on my dedicated foil board had way too many spin outs. You have to remember it is not designed nor tested with pressure from a sail and the position most people ride it on the board is different from most wind foil boards.
I would have at least 1 or 2 spin outs on every run in and out. On the Naish I have a spin out perhaps once every few months. I can only remember 2 ever.
If possible, if you can pair the Naish with a board that has a track on the bottom instead of a tuttle that would be the best combination. I currently have the JP 155 foil with a tuttle and I would love to move the foil up about 1 inch because I use way too much back foot pressure in light wind or no wind.
What I mean by no wind is my goal once on a swell is to have no sail power at all and just surf it with the sail flagged out. I find this is a lot of fun, but after riding a long swell I notice my back leg becomes tired because of the needed back leg pressure.
Naish has a new board coming out that is larger than the current board which might be my solution. Currently I do not see anything else that would work in a size I like. |
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d0uglass
Joined: 28 May 2004 Posts: 1286 Location: Bonita Springs, Florida
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Posted: Thu Mar 08, 2018 8:32 am Post subject: |
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Bryn, would you say the Naish Thrust WS pops up similarly early and easy to the GoFoil, but is just more controllable with less spinouts? Or is it a tradeoff? I wonder if the Naish foil would work well on the Exocet 8'11 windsup, which has the tuttle box forward of the US finbox. _________________ James' Blog: Windsurfing Equipment Size Calculator
http://jimbodouglass.blogspot.com/2010/11/updated-windsurf-calculator-online.html |
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brynkaufman2
Joined: 10 Sep 2002 Posts: 383 Location: Kailua Oahu
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Posted: Thu Mar 08, 2018 12:44 pm Post subject: |
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I think the Naish pops up sooner and also at the same low speed. Probably because it does not spin out so you can actually put more sail power into it when that gust comes.
It is definitely faster and more controllable. Not only does it not spin out, but it does not have that feeling of wanting to foil out which I felt a lot with the Maliko.
For my weight of around 160 lbs. the Maliko was way too much foil.
If you notice the Naish WS foil has a rear Integrated Rudder Foil that their SUP foil does not. I believe that is why it does not spin out.
I do know of two windsurfers that like the Maliko. They are heavier and they have it located further up on a custom board, not in the very back like most wind foil tuttle boxes are. I assume this is why they did not experience the problems I had with it.
So for me there was no tradeoff, the Naish performed better for me in every way. |
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ittiandro
Joined: 22 Nov 2009 Posts: 294
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Posted: Mon Mar 12, 2018 1:42 pm Post subject: Hydrofoil wing towards the middle of the hull? |
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I WONDER IF A HYDROFOIL WING ON A LONG BOARD LIKE THE WINDSUP ( 11.6 FT) DOESN'T MAKE IT HARDER FOR THE HULL TO RISE ABOVE THE WATER OR ANYWAY TO PLANE, AS COMPARED TO A SHORTER BOARD, BECAUSE THE LONGER THE BOARD THE MORE THE WEIGHT AHEAD OF THE HYDROFOIL WING?
WOULDN'T THE BOARD RISE MORE EASILY AND BE MORE BALANCED, TO BEGIN WITH, IF THE HYDROFOIL WING WAS ATTACHED MORE TOWARDS THE MIDDLE OF THE HULL, PERHAPS EVEN DIRECTLY ON THE CENTERBOARD BOX?
JUST WONDERING ..
ITTIANDRO |
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