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 Post subject: Collaborating Ideas - Long distance board
PostPosted: Sun Feb 17, 2013 8:53 am 
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Joined: Sun Jul 15, 2012 9:32 am
Posts: 87
Location: Tauranga, New Zealand
Hi all,
I was hoping that as many people with board knowledge could help to make an awesome long distance journey board!

Photos and actual plans will be uploaded when changes happen so that anyone can build. :thumb:

Specifications Needed:
- great in a wide range of conditions and wind strength - 11kn+
- Stable at high speeds
- Ability to go through shallow(ish) water e.g. just above knee height ( fins not as long as raceboard, more than tt)
- go over chop easily
- be very efficient
- not be to intense to ride, so that long trips are easier.
A few others will probably be added!

Currently in the research and planning stage, will continue to edit.
Looking forward to everyone's ideas!

:D


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 Post subject: Re: Collaborating Ideas - Long distance board
PostPosted: Sun Feb 17, 2013 11:25 am 
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Joined: Thu Apr 10, 2008 3:49 pm
Posts: 34
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that's what i do for cruising. Kind of a down scaled raceboard. The CoffeeRacers are realy easy to ride and can be used with fins from 20 -30 cm. If this is what you are looking for i can post more details. http://www.ahcustoms.ch


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 Post subject: Re: Collaborating Ideas - Long distance board
PostPosted: Tue May 14, 2013 11:22 pm 
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Joined: Sun Jul 15, 2012 9:32 am
Posts: 87
Location: Tauranga, New Zealand
Just bumping (=

anyone else have any ideas?

now starting to design for a long distance ocean reace, needs to be able to average 18-20kn over 250km, mild ocean chop


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 Post subject: Re: Collaborating Ideas - Long distance board
PostPosted: Tue May 14, 2013 11:30 pm 
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Joined: Fri Sep 11, 2009 3:15 am
Posts: 1436
In prototyping i would ride the board strapless in different conditions and mark the position with even front and backfoot pressure if going long distances on one tack.


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 Post subject: Re: Collaborating Ideas - Long distance board
PostPosted: Wed May 15, 2013 5:12 am 
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Joined: Tue Jul 19, 2011 5:26 pm
Posts: 194
Location: Langebaan (Cape Town)
The other commercail board made for this type of requirements is the Airush sector. And then you can scale down to a wide surfboard if you don´t need so much performance and want an easier ride.

I think choose what performance and comfort level you want. For max comfort with decent light wind and wind range, go for a wide surfboard shape. For better lightwind and upwind go for a sector shape. For even better lightwind/upwind, go for the Stealth coffee racer. And then full raceboard is obviously the next level, but not what you want.

I would go for a board between a wide surfboard and a sector for what you want, especially if you do not plan too much upwind riding.

Strapless to test foot position is a great idea. I would use the board strapless for the journey as well, as it is so much more comfortable on a long trip to have you rfet free and be able to change your stance slightly, but if you want to go fast over chop then straps will be better.

If you did not have the shallow water requirement then I would have chosen a hydrofoil as its performance in upwind, lightwind, chop handling, comfort and rider fatique beats all the other boards by a long margin. But is does need deep water and unknown underwater obstacle can be a disaster.


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 Post subject: Re: Collaborating Ideas - Long distance board
PostPosted: Thu May 23, 2013 11:01 pm 
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Joined: Sun Jul 15, 2012 9:32 am
Posts: 87
Location: Tauranga, New Zealand
Hi guys
thanks for the responses
I have gone for ChristoffM's idea of a hydrofoil

it has an extremely efficient foil profile, and the foil is extremely high AR, not for the feint, maximum efficiency is at about 22kn, takes 13kn to get up. - but a degree of movement is enough to almost drop you.
designed for one purpose only, to go in a straight line fast.
so far ~


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 Post subject: Re: Collaborating Ideas - Long distance board
PostPosted: Fri May 24, 2013 5:19 am 
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Joined: Tue Jul 19, 2011 5:26 pm
Posts: 194
Location: Langebaan (Cape Town)
What CAD program are you using? The carbon fibre texture looks very realistic.

I assume its a joke just to play with CAD? Or are you really attempting building a super high aspect high efficient hydrofoil?


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 Post subject: Re: Collaborating Ideas - Long distance board
PostPosted: Fri May 24, 2013 1:47 pm 
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Joined: Sun Jul 15, 2012 9:32 am
Posts: 87
Location: Tauranga, New Zealand
Hi,
that was done on solidworks.
Yes I am going to try make a successful high AR Foil. although right now it has a AR of about 18 - might reduce to 12 or 13, which will be closer to a hydro foiling moth's 9.5 (18 will only be good if a stabilising method is found)
the profile is finished :thumb:
finalising the rest of the design atm
only issue so far is that even though the rear foil is 1.5m away, a 3-4cm chance in its height is about 1 degree - enough to +/- a few hundred N of force.
going to look into the rear foil being electronically stabilised. - although there might not be enough room for sensors and stepper motors


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 Post subject: Re: Collaborating Ideas - Long distance board
PostPosted: Fri May 24, 2013 5:51 pm 
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Joined: Tue Jul 19, 2011 5:26 pm
Posts: 194
Location: Langebaan (Cape Town)
Wow, now that sounds like an interesting project. Have you rode a hydrofoil before? The step up from a low aspect to the current high aspect designs are apparently quite a big step in difficulty, and the current high aspect kiting foils are not nearly as high aspect as what you have in mind. And 1.5m front to back? Interesting.

I do not think height control is the issue too much. I think it is the sudden stall you get for changing the angle of attack too much on a super high aspect foil will be the problem. But with 1.5m fuselage length that should not be a problem. The next problem will be getting enough speed before lift off.

If the moths can do AR of close to 10, then it would probably be possible. But only in flat water I would think.

What profiles are you going for? Some Eppler hydrodynamic ones?


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 Post subject: Re: Collaborating Ideas - Long distance board
PostPosted: Fri May 24, 2013 11:50 pm 
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Joined: Sun Jul 15, 2012 9:32 am
Posts: 87
Location: Tauranga, New Zealand
The profile is based off using NASAs basic program foilsim
it was made using experimental data but is better than anything else that I have been able to find. (nothing)


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