Are any of you exploring the realm of thick (0.75'' to 1.0'') foiled fins? I've had ''very good'' boards blossom into ''magic'' boards, with the simple exchange of a thick foiled fin for an existing standard thickness fin. I'm having FU make some for me now, some high aspect ratio reverse fins.
bert burger was a big fan
other than that, id like to try them yes, thrusters?
aero/hydrodynamic theory tells me they will work well at low speeds and should turn great, I predict you will have a hard time getting them to slide out. Excited to hear what happens in practice…
Not sure if you remember but about a year and a half ago at the surfing heritage foundation workshop you put on we had a good discussion about this. Pending your feedback I just might have to try it out.
Take care Bill!
Durbs,
I've ridden one inch thick Black Walnut, foiled fins, in Hawaii up to what Buzzy Trent called twentyfive feet. On the boards that I employed thick fins, I NEVER spun out. And I had the ability to turn at any time, anywhere on the wave I chose to, without loss of control. It's a real confidance builder! For shorter base fins (6'' or less) you want to hold it down to 3/4th to 7/8ths inch thick, IMO.
Bill,
What base and heignt fin are you using a 1" thick foil on?
Durbs,
On the '60's guns, the base was 10 1/2 inches, height 6 3/8ths inches. In the '70's, shorter boards, it was 6 inch base, 7 5/8ths inch deep, 3/4 inch thick base FU lexan Brewer shape fin. The ''new'' reverse fins being done have a 7 inch base, and 8 1/4th inch height.
http://en.wikipedia.org/wiki/NACA_airfoil
for a roughly 6" base 1" thick foil is about 17%.
Edit: Many popular NACA foils are at 12%… 3/4" thick is right at 12%. Dont think it is any coincidence that you found it to work and work well.
btw, im a fan of hemingway, was actually going to pick up for whom the bell tolls soon and read it for the second time, its a good book!
You talking about fins like these…???..Been doin’ 'em like this for years…
Yes, similar, but way smaller.
Have to agree with you Bill, and have only had good experiences. Mind you I never surfed anything over about 12' thick Victorian waves.
All the current foils I use are computer generated, and the low speed symetric hydrofoils are 12.5%. People can only ignore science for so long.
Hey Bill...
Thick foils...The glassed-on twins are 12mm, the plugged twins 16mm and the thruster 12mm.
I've done others and ridden them exclusively on the FCS'd twin fin Less drift when pushed hard.
Josh
The NACA 2412 foil is not a symmetric foil, it is a cambered foil (as indicated by the “24” in the NACA number–see your wikipedia reference).
Attached is a picture of a kneeboard with thin, flexy, rails (sheet glass) and a 1" thick, symmetric, foam/glass fin from around 1971 (date can be verified as a picture of the board appeared in SURFER while it was under construction).
thanks for correcting my mixup… didnt read through that thoroughly. my bad. I was trying to get at the 12% point, got lost in the details.
…hello Bill,
I think you are right
seems that thicker foils perform better in smaller weaker surf
but to do a fiber/resin super thick fins is a no no for the weight so I did some in wood (to avoid ballast)
that worked fine in egg shapes (thrusters)
hey bill and all,
I can’t report on the scientific side of the thick foils, but I regularly foil twin keels - both std and cutaway/progressive - out of 5/8 or 3/4 ply. They feel much more positive in terms of drive, hold and direction in turns than the fiberglass versions. It has allowed me to ride a 5’8" in some pretty gnarly conditions where I would rather have something bigger. And like you’ve said the spin outs have all but stopped.
Definitely something going on there…
don’t you want a thinner foil for higher speeds?
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don't you want a thinner foil for higher speeds?
i [/quote]
In general, yes. With the thicker foils the goal is no fin stall at high AOA, abrubt turns, and maintaining laminar flow on the fin. The thinner foils come into their own at higher than surfboard speeds. For perspective, in big Sunset, and Waimea, Bob Shepard measured speed on the drop between 25 and 28 mph, though I have to tell you it feels much faster.
what about a quad set up with two thick fins and two thin ones? would they cancel each other out or both work in their respective speed ranges the way they are intended for?
Well - Bill… You’ve mentioned this for years… Good to see it getting “out there/here.”
As we’ve been looking at recently - more than one way to keep the flow going…