thick fins
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Re: thick fins
Dunno about faster in a straight line, unless you mean the thin ones are flat and don't have foil.
A thick fin supposedly has less drag I.e. turbulence and is better for direction changes.
I've ridden some very thick windsurfing fins, close to an inch thick.
Put one in a short single and it was very smooth, but the fin wasn't foiled properly it was pretty huge
A thick fin supposedly has less drag I.e. turbulence and is better for direction changes.
I've ridden some very thick windsurfing fins, close to an inch thick.
Put one in a short single and it was very smooth, but the fin wasn't foiled properly it was pretty huge
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Re: thick fins
I haven't experimented much between thick and thin fins, however to my understand the stiffer the fin the more drive it can produce, but to the detriment of responsiveness compared to a fin which flexes more and is easier to overpower.
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Re: thick fins
Our good mate Roy uses this as reference (I believe) for both board shape and fin foil...saltman wrote:Seems almost counter intuitive that a thick profiled fin will be faster - but look at the front edge of plane wings
Re: thick fins
From what I remember of fish locomotion lectures the thickest point should be 1/3 to 1/4 from the front.
Re: thick fins
I'm a great believer in PHI (1.618) for most things, think it might migrate pretty well to this. So I work elements around the decimals and use 'em as a percentage 62% and 38%saltman wrote:Nice so thickness should = 10% of length
But where do you position the thickest foil?
In some of my fins the thick point seems to vary along the lenghtg at different heights of the fin ?
So my application would be put the widest point 38% of the way through the cord length.
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Re: thick fins
fongy it all depends what you mean by "faster".
If you mean "more slippery" (like creating less turbulence and thus less drag) then it's all about getting the foil right, not so much the thickness per se.
I'd imagine boo's sailboard fin was thick because the designer wanted it to be stiff as a board and not flex around, not because of any foil advantage.
Foil is pretty much a settled issue, you want to go to a good boat designer and talk to him/her -- if you're lucky he/she might use some design software and draw you your very own perfectly foiled fin CAD program. Then you can go get a fin plate and get it cut to order. It'll cost a bit but most good design does.
I guess what I'm saying is that it's all been done elsewhere outside the surfing world, no need to re-invent the wheel on foils.
If you mean "more slippery" (like creating less turbulence and thus less drag) then it's all about getting the foil right, not so much the thickness per se.
I'd imagine boo's sailboard fin was thick because the designer wanted it to be stiff as a board and not flex around, not because of any foil advantage.
Foil is pretty much a settled issue, you want to go to a good boat designer and talk to him/her -- if you're lucky he/she might use some design software and draw you your very own perfectly foiled fin CAD program. Then you can go get a fin plate and get it cut to order. It'll cost a bit but most good design does.
I guess what I'm saying is that it's all been done elsewhere outside the surfing world, no need to re-invent the wheel on foils.
Re: thick fins
Mate, played with the formula with boards, but hard to know how and where to apply so gets a little confusing to say the least.fongss wrote:ric_vidal wrote:
I'm a great believer in PHI (1.618) for most things, think it might migrate pretty well to this. So I work elements around the decimals and use 'em as a percentage 62% and 38%
So my application would be put the widest point 38% of the way through the cord length.
interesting ric....i'm thinking a board and fins made too that formula
the foil of the fin matching the foil the board
I reckon it isn't a bad formula for volume though, slightly different to Feral Dave (.35).
- dUg
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Re: thick fins
Ever so slightly hinting at Reynolds Numbers there Ric?
Pretty much every mainstream fin manufacturer uses the NACA foil... in fact... they pretty much use the identical foil. Sure... tweaking outlines, different flex chx & materials etc have an effect, but it's only experimenters and foil nerds who play with the foil.
I have some fins in my posssion that DON'T use the NACA foil ( which arguably was desgined for aircraft wings with mostly straight leading and trailing edges ), BUT maintain a constant foil. I have reasons behind it I won't broadcast here, but everyone who's surfed 'em loves 'em.
As for thicker foils... much thicker = more surface area = more drag, but given the inherent turbulence at the base of anything that isn't a glass-in fin it's all relative.
Pretty much every mainstream fin manufacturer uses the NACA foil... in fact... they pretty much use the identical foil. Sure... tweaking outlines, different flex chx & materials etc have an effect, but it's only experimenters and foil nerds who play with the foil.
I have some fins in my posssion that DON'T use the NACA foil ( which arguably was desgined for aircraft wings with mostly straight leading and trailing edges ), BUT maintain a constant foil. I have reasons behind it I won't broadcast here, but everyone who's surfed 'em loves 'em.
As for thicker foils... much thicker = more surface area = more drag, but given the inherent turbulence at the base of anything that isn't a glass-in fin it's all relative.
Re: thick fins
Had never heard of it, dUg, until your reference. I just don't have the head for those formulae.dUg wrote:Ever so slightly hinting at Reynolds Numbers there Ric?
Nah, just think nature has a knack, but it's all about numbers ultimately.
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Re: thick fins
Most pros use fin systems.
Not one pro in the top Ten uses glass ons.
Not one pro in the top Ten uses glass ons.
I want Nightclub Dwight dead in his grave I want the nice-nice up in blazes
Re: thick fins
Hmmm, are you absolutlely sure about that Steve? I know without a doubt that when Taj was riding Firewires last year they were all glass-on's, which was his preference, and the Mayhem he won this year's Snapper event also had glass ons.....steve shearer wrote:Most pros use fin systems.
Not one pro in the top Ten uses glass ons.
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Re: thick fins
You're right, I'm wrong.
By my obs at Snapper and Bells Taj is the only pro in the top 16 rocking glass-ons.
By my obs at Snapper and Bells Taj is the only pro in the top 16 rocking glass-ons.
I want Nightclub Dwight dead in his grave I want the nice-nice up in blazes
Re: thick fins
Other question would be, was it really a Firewire?damo666 wrote:Hmmm, are you absolutlely sure about that Steve? I know without a doubt that when Taj was riding Firewires last year they were all glass-on's, which was his preference, and the Mayhem he won this year's Snapper event also had glass ons.....steve shearer wrote:Most pros use fin systems.
Not one pro in the top Ten uses glass ons.
Re: thick fins
I don't think Taj is riding FWs anymore. I ready Matt Biolos' blog (mayhem / lost) and he seems to be doing a few for him (and everyone else!)
Biolos seems to have his head screwed on the right way. Does some lovely looking boards, and you know what they say - if it looks right....
JG
Biolos seems to have his head screwed on the right way. Does some lovely looking boards, and you know what they say - if it looks right....
JG
the tools of the trade are the head and the heart - mission of burma
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Re: thick fins
He mustn't have worked out a fin sponsor yet - he'll have to sack the manager!steve shearer wrote:You're right, I'm wrong.
By my obs at Snapper and Bells Taj is the only pro in the top 16 rocking glass-ons.
Re: thick fins
No he isn't, but that wasn't the inference.collnarra wrote:I don't think Taj is riding FWs anymore.
JG
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