and yes i have done a search. i cant seem to find an answer.
i have some small fins from a kite board and i was thinking of using them as bonzers but there foiled on both sides.
is this gunna cause problems?
i need help Dr phil!..
Double foiled fins work best straight ahead and straight up. They’re symmetrically foiled, so there no difference in water flow on either side of the fin, except when angled to the flow of water. I rode double foiled Speed Dialer rear fins toed and canted, and they just didn’t have the lift or drive. I replaced them with single foiled fins and the difference was dramatic. Single-foiled fins work best with toe and cant, so I’d stay away from glassing the fins you have onto a bonzer.
Speedfins have a 10 degree foil on the inside, they work alright. I think if the more foil the straighter the fin.
what the heck is a 10 deg foil? Is that like a bucket of propwash?
Hey shifty,
NJ is right on. A single foiled fin generates more lift in one direction than a double foiled (symmetrical) fin does. In order to produce zero lift going straight ahead, a single foiled fin MUST be toe’d in (how much depends on the actual foil shape, usually around 3 degrees). A symmetrical double foiled fin must be placed with zero toe to produce zero lift straight ahead…
A double foiled symmetrical fin will generally stall later than a single foil, but the single foil can generate more lift before stalling…
JSS
If you use FCS or Probox you can just grab a few extra tail fins and put them in as rail fins and see…
the board will still work pretty well, not as nice as with single foiled rail fins, of course.
The single foil evolved with glass-ons, and the fins were foiled on the board. Saved the glassers a lot of work and actually worked better.
Shifty,
The area on wakeboard fins is so small that I reckon the difference between flat side and full foil will be marginal. At that size the fin would be more about a little bit of bite…drag for control…rather than lift. Or at least not unless you are doing bullshit speeds, which surfboards don’t…
I doubt it would cause you any problems to use them. Go ahead and try it I say. Or try it, then some with flats inside…see what you reckon.
Josh
can outside fins be foiled both sides?
yes, i prefer them double foiled
the beauty of making my own fins , is that i can use them as back , sides , and also single fins , that
makes changing fins quicker and easier for me
i posted on this a while ago , but only got one reply ["when did side fins become SINGLE foiled ,
and
WHY ?? "]
cheers mate
ben
hey josh…
these are the fins i was thinking of using.
and this is the board they might go on.
i like single fin boards and the way they surf but i would like a little more drive and hold through bottom turns. do you think these fins would help for that or are they just too small to begin with?
Shifty…
I know what you want…Check these out:- I pulled them out of the rafters for you. What was I on back then???
But the side bites do work.
I would’nt be too concerned about the two sided foil on those fins of yours…with the big single fin doing most of the work you should get a nice touch of extra out of those.
My only concern is:- Are your wakeboard fins plastic or glass? If you have molded plastic, they may not stick, and I know you are not going to drill holes in that hollow board!
im not sure what you were on back then, but you should keep taking it if you ask me. those boards are sick!
the kietboard fins are glass. epoxy or poly? not really sure…
no, i will not be drilling holes in my board for them. i was just gunna glass em on.
i cant really tell from the shots but are they pointing strait ahead or raked in slightly? kinda looks like there pointing strait maybe?
cheers for going out of your way to get the boards down… you need to surf those bad boys again!..
Shifty…
If they’re glass, then whatever you use should stick fine after a good roughing-up.
Toe-in on the trippy one, parallel on the cosmic one.
Hehe, no, really, the one with the hideously long base is parallel. I did’nt ride that one much…the curved step-bottom is as weird as it looks, but the round pin was a rocket!
Yours puts 'em to shame for craft man…
Josh
Speedneedle,
I have 2 questions:
how do you obtain big pict to post in 28 K format?
is the black pinline on the foam? which paint or tint did you used to obtain that smooth and dark black on foam?
thanks
Dont know much about kite fins, but most of the big fin co’s are making double foiled fins these days, proly too many of them. IMO, its mostly profit driven. I like flat innards.
Reverb…
That particular black pinstripe is on foam, just automotive black in a small spraygun…Pinstripes on the hotcoat are easier to get sharp-looking, and indeed this one on foam has some tiny tell-tale bleed in the nose where the shaping scratches are more prominent. Sometimes I would do a combination of foam and hot coat paint for different effects.
The photos have to have the image size reduced to under a meg in Photoshop, then saved for web- (Shift-Ctrl-Alt-S) which compresses them way down.
Sways inline shots need to be under 34k
Josh
Craftee,
I disagree for two reasons…
kiteboarding - the forces on a board and the effects of fins are different - Theyr’e being dragged by solid windpower and the issue is not so much to create lift as to prevent slide.
Secondly, double foiled fins are more difficult to make, either in hand foiling or molding.
Josh
Inside foils on side fins optimize fins into specific corners of the performance envelope. Flat sided fins work better over a broader range of the performance envelope. Fins need to perform two functions. The primary function is directional control which optimized with high lift low drag foils. The second function is kinetic propulsion which is pumping or swimming to a more powerful part of the wave. Convex inside surfaces are higher lift and lower drag than flat sided or concave inside surfaced side fins. However, they shed water rather than grab water when they are pumped. So, they are not great fins for mushy conditions. But, they are great fins for control in powerful surf because they reduce leading edge drag and can handle greater angles of attack without creating turbulent eddys. Concave inside foiled fins pump exceptionally well. But, they create more turbulence at shallower angles of attack and lower flow rates. Flat sided fins cover both areas adequately. But, they don’t excel in either.