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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Tue Feb 11, 2014 12:43 am 
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holden wrote:
@davesails7: i disagree with your conclusions. with kitesurfing it is almost allways about dynamic lift. volume only creates static buoyancy. you only need static buoyancy when standing on board with virtually no speed at all. for example when you do a tack and fail to loop the kite on time volume prevents you from sinking.


True, dynamic lift starts to support you as soon as you start moving, but it doesn't become all dynamic lift right away. At slow speeds your weight is supported by a combination of both. As you speed up a larger portion of your weight is supported by dynamic lift (proportional to area as you said) and less by the buoyant force of the submerged volume.

I haven't ridden a foil board yet (so this might all be total BS :wink: ), but on my raceboard the volume really helps to get going in the ultra light wind. When it is really light I can only get going if I start with the back foot in the center of the board and use the buoyancy of the board while I sine the kite up and down. Between dives of the kite the board can come to almost a complete stop, but the buoyancy from the volume keeps me afloat and in the correct position until I can get up enough speed (or get a gust) to start planing, put my back foot in the strap, and load up the fins.

I'm guessing you could do the same on a foilboard with extra volume in very light winds. It seems like by the time you have enough speed/power to get the board to plane and provide enough dynamic lift, you would have had enough speed/power to get lift from the foil. The foil provides dynamic lift, but is more efficient than your board is. A little more than 1 square foot of foil can support you in <10 knots where if you assume half of a light-wind twin tip is planing surface you're at over 3 square feet of planing area.

Also when racing you need the volume in your foilboard to slow yourself down at the start line, but still be ready to take off at the gun. Another thread had a discussion about a race that included raceboards and foil boards on the same course. The raceboards were able to slow to an almost stop on the line waiting for the gun, but the foilboards had to come in with speed, so the foilboards couldn't get as good of a start. They were always starting behind the raceboards.

Again, I've never even ridden a foil yet, so I could be totally wrong. From my raceboard experience though the extra volume to get up to speed in underpowered conditions and maneuver before a race makes a lot of sense to me. I've very interested to see how this all works out once the Foil races start in a few months :thumb:


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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Tue Feb 11, 2014 3:14 pm 
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@davesails7: we will see how things develop... i am totally happy with the board size and volume of my foilboard deck right now. on the other hand i will not do any hard core foilboard racing so i need not to optimize in that direction.


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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Wed Feb 12, 2014 11:47 am 
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Hi Everyone,

I try to stay out of other peoples post, but I feel the need to clarify a few thing, or at least give my perspective on this topic.

1) Volume: I to not think a Foilboard (Race or otherwise) needs the amount of volume that are being pushed at the moment. The reason for the 8cm Board thickness is so they can accommodate the Deep Tuttle Box.

What I have found ist that surface area of the bottom of the board is more key to getting up and flying than large amounts of volume. I have compared using a 2cm thick board to a 8cm board and it was just as easy for me to get flying in the really light stuff (less than 8 knots).

What I personally really dislike about the high volume boards is the disconnected feeling I get. The thinner the board, the more directly connected to the foil I feel. I love my Black 120x45cm Foilboard. It may be a bit technical to ride, but it feels so much more alive than riding the same foil on a bigger board.

2) Bigger Wings: For the normal joe getting a bigger wing will help you progress so much faster and give you more fun than a small race wing. The speeds you can achieve are still damn fast and doing manoeuvres like Airtacks and Gybes become really easy. I have made wings of 102in2 (half span) which allow me to air tack 100%. On race wings that drops down to 50%.

And what is the speed difference? Not as much as you would think. Cruising Speed on my fastest AR 8 Race Wing on a broad reach is about 45km/h. Top speed is about 55km/h. Top speed, however, really depends on what you as a rider can handle. On the lower AR 6.6 the cursing speed on broad reach is about 40km/h. That is only a 5km/h difference. Sure in a Race that is huge, but how many of us will be hardcore racing in the new future. The pros, in my opinion, far outweigh the cons in this respect. The biggest being, that you can get/keep flying at lower speeds.

I have read the argument that a wing designed for 5 knot will not work well at 40 knots as the wind will create to much lift. That is a little bit oversimplified. The lift of the front wing will be held in check by the rear stabiliser wing if the Foil is balanced. So no matter what the speed, the Foil should track straight and should not try to push itself up out of the water. At least that is how mine work.

3) Slowing down at the starting line at races. Even with race wing you can slow down just as much as you can on a Raceboard. The question is, do you want to? When the whole fleet is experienced and knows what they are doing the starts are quite fast and no one stalls before the start. In a large fleet you always look for space at the line so you don't have to stall.

4) Getting so focused on racing: I am a racer. I did course racing at an international level for 7 years. I can understand the hype in the racing scene. But I cannot understand why everyone thinks that all we need to push right now is the racing side of foiling.

I see is more as a perfect quiver situation: You can travel anywhere with a small surfboard bag with one board system. Surfboard with Foil. So light winds and strong winds are covered. Biggest kite you need is a 13m2. This is what really gets me stoked about foiling and why I started to develop foils in the first place.

--
Gunnar


Last edited by gmb13 on Wed Feb 12, 2014 8:39 pm, edited 1 time in total.

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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Wed Feb 12, 2014 7:03 pm 
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Great insight Gunnar :)


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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Wed Feb 12, 2014 10:33 pm 
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gmb13 wrote:
I have made wings of 102in2 (half span) which allow me to air tack 100%.


Hi Gunnar,
can you please specify a little bit this size? Is it realy 100 in² for only half a wing? Front and back wing combined (up- and downlift)? What do you mean by half span?
Sorry I just try to get the math and reality clear.
THX :baby:


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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Thu Feb 13, 2014 12:56 am 
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I agree with Gunnar. What is really needed is a semi fast, stable foil system. One that doesn't ventelate over chop. One that doesn't pitch excessively with slight weight changes. One that handles more like a surfboard than a bicycle. This prototype is almost perfect but still a work in progress.


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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Thu Feb 13, 2014 1:23 am 
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calvin_1 wrote:
gmb13 wrote:
I have made wings of 102in2 (half span) which allow me to air tack 100%.


Hi Gunnar,
can you please specify a little bit this size? Is it realy 100 in² for only half a wing? Front and back wing combined (up- and downlift)? What do you mean by half span?
Sorry I just try to get the math and reality clear.
THX :baby:


102in2 Total Surface Area (top and bottom) of the Half Span of the front wing. eg. 204in2 the whole front wing.


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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Thu Feb 13, 2014 5:41 am 
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Joined: Mon Aug 12, 2002 1:00 am
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Location: Miami @ 6" Flat Butter!
Gunnar, good information :thumb:
I like your SUP foiling video which is obviously not a race board belonging to the topic,
but I'm interested to convert a SUP board and ride like that also with a multi purpose board,
in super light session going to places fast, than doing SUP Yoga, paddle boarding exploring, etc.
Would you share your experience and if the SUP board had some advantage in certain area,
since just by looking at the video didn't look like there was any disadvantage :?:

Thanks,

DrLW (Bela)


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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Thu Feb 13, 2014 6:26 am 
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Even though I always love a good debate. This one has gone off topic. Of course there are different needs for foils and foilboards. Freeride, race, waves and so on. Personally I dont care about freeride and waves on a foil (freeride foils have been here a decade without succes. I have had a Carafino and compared to a racefoil it dont turn me on). And in waves I still prefere the original style.
But when racefoils hit the scene foiling took on to litteral a new level. And I think what this thred is about too. New racing equipment ;) What can get us around a course the fastest. And when we talk racing I believe volume in the board makes sence. Just like on a raceboard. Especially in marginal wind where you need to pump the foil up in speed before getting on a plane. And yes.You sometimes need to do that when the pull of the kite alone dont get you foiling. Then you first pump the foil and the higher volume help the board being light on the water and you fly again


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 Post subject: Re: Carafino: Race Board 2014
PostPosted: Thu Feb 13, 2014 4:03 pm 
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lander wrote:
Even though I always love a good debate. This one has gone off topic. Of course there are different needs for foils and foilboards. Freeride, race, waves and so on. Personally I dont care about freeride and waves on a foil (freeride foils have been here a decade without succes. I have had a Carafino and compared to a racefoil it dont turn me on). And in waves I still prefere the original style.
But when racefoils hit the scene foiling took on to litteral a new level. And I think what this thred is about too. New racing equipment ;) What can get us around a course the fastest. And when we talk racing I believe volume in the board makes sence. Just like on a raceboard. Especially in marginal wind where you need to pump the foil up in speed before getting on a plane. And yes.You sometimes need to do that when the pull of the kite alone dont get you foiling. Then you first pump the foil and the higher volume help the board being light on the water and you fly again

:thumb:


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