thick fins

[Roy_Stewart]

Foil is pretty much a settled issue

Let's face it you don't know what you are talking about, but feel the need to express an opinion anyway.

Said opinion consists of basically saying 'shut up and leave it to the experts' while giving the impression that you are one, when you are not.




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[Roy_Stewart]

Anyway, I usually use laminar foils. These are foils which have the thickest part back at 45 to 50 percent aft. They are lower in drag provided that the angle of attack is relatively low, and they are kept clean.

Thickness wise the accepted range for marine foils is 9% to 14% of the chord length, that's just a rule of thumb though and as we have seen surfboard fins down to 6% work very well, as do thicker ones.

To some extent thickness is related to the position of the thickest part of the fin. for example a thinner fin can be used if it has the thickest part of the foil well forward at say 25% to 30%, conversely a thicker fin can compensate for the thickness by having the thickness aft. That's what I tend to do.

By the way NACA foils are not always ten percenters. The NACA number tells us what the foil parameters are : http://en.wikipedia.org/wiki/NACA_airfoil

[dUg]

[dUg]

... and if you think I'm posting cross sections in a more easily copyable projection, think again.

[ric_vidal]

rincon_solid.jpg

Looks well made dUg, pity about the pasty hand holding it

I'm still a little surprised someone hasn't included a little design element to their fins - well they have but it was a piss poor construction... more on that another day.

May have to talk to you about that one.

[Roy_Stewart]

What design element is that?

[dUg]

What design element is that?

I'm not sure what you're asking here Roy.

If it's about the image then it indicates 2 slices ( sections ) through a solid model fin, one through the base and one through the length. The vertical cross section is also parabolic, side and center fins use the same curve.

fong a few curve balls on the home front delayed your package, it's on the way. BTW... that base curve will be no use to you unless you understand how it's applied through the length of the fin.

In the meantime, here's something else to get you thinking...

http://www.3d-printers.com.au/

[Roy_Stewart]

What design element is that?

I'm not sure what you're asking here Roy.

If it's about the image then it indicates 2 slices ( sections ) through a solid model fin, one through the base and one through the length. The vertical cross section is also parabolic, side and center fins use the same curve.

I'm asking what Ric meant by this:

"I'm still a little surprised someone hasn't included a little design element to their fins - well they have but it was a piss poor construction... more on that another day."

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[Roy_Stewart]

http://www.theinertia.com/surf/thinking ... n_ref_map=[]




always refreashing read someone else is into the same thing u are

even if it looks weird

Sorry but that article is retarded, it suggests that by eliminating fins one can eliminate drag.

It's the same BS we hear constantly from Wegener and others.

[ric_vidal]

I'm asking what Ric meant by this:

"I'm still a little surprised someone hasn't included a little design element to their fins - well they have but it was a piss poor construction... more on that another day."

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Don't choose to say at the moment, Roy... I think I need to build a set and see what happens. Started a year ago and hit a wall, or a series of walls called overseas surf travel.