finlets....

[dk]

u know...the little gay lookin things some dudes have in front of their fins.

anyone tryed em? not calling bullshi* on em..just curious what ur outcomes have been.

i met a guy who swears by em...said soemthin about it cleans up the water befor it hits the fin

 

[dk]

<img src="/forum/images/graemlins/shrug.gif" alt="" />

 

[000]

well the rusty c5 kind help a little, but its pretty hard to tell. pretty much the same feel as putting in slightly larger side fins in a thruster

 

[hackeysaky]

I find it funny you say "little gay lookin things" and "not calling bullshi* on em" in the same post. Seems kinda contradictory.

I'm friends with the guy who came up with the concept. The idea is to mimic the effect that the little caudal finlets in front of a tuna's tail has... that is, to create small vorticies (spinning water) infront of the high-aspect ratio tailfin, thus reducing drag along the base of the fin where it attaches to the board.

He has done a ton of research on the topic (some of it with my help) and I'd say he has some sound principles. I have them on some of my boards- IMO, they definitely do not seem to be slowing anything down (as so many people say they will), and I think they give the fin cluster a little more mobility (something I like in my boards). Similar to the C5 concept, but with some technical differences.

So far repeat users include: Matt Kechele, Nick Guilarte, John Holeman, Greg Loehr, Sam (Loehr's right-hand man), Herb Spitzer, a number of guys in NJ (myself included), and a bunch of other people I don't recall at the moment.

 

[blakestah]

To my knowledge, Wil Jobson invented them when he invented the twinzer. He lives very far indeed from New Jersey. Herb Spitzer claims he started with Jobson's work.

I've ridden the Superchargers. MVGs, and twinzers. The difference between a twin and twinzer seemed much larger than the differences in adding the finlets to a thruster.

There's a large theory vase on such vortex generators - the F18 uses a strake vortex generator.

 

[rolliges]

I have them on a few boards. I really like beating beachbreak sections while standing on the nose with the curl just in front of my feet. Holding back; don't want to outrun that curl do you?

 

[dk]

haha sorry hack if i offended you. i guess i could ahve chosen a few better wordsas my description.

they are kinda gofy lookin though.

you dont see many around. i figure if they are so inexpensive...why dont people give em a try?

the reason i thought of this question acually is because i saw a set of them on a board at gregs place, and i remembered Rob Olliges responding to a thread at swaylocks about em.


so noone ha still said exactly how they help. i realize its supose to clean up the water and everthing in front of the fin....but can u notice the difference?

do u guys feel the difference in turns? like a solid cutback,...does it feel not as loose due to the little finlets givin some resistance?

thanks for your opinions fellas. i might buy some sometime to try em out.

only problem is there'sno waves <img src="/forum/images/graemlins/frown.gif" alt="" />

 

[blakestah]

How they work......my working theory.

On the low pressure side of a fin, water swirls in a vortex created around the leading edge. This vortex helps create lift - it is a part of fin action.

The little finlets are vortex initiators, that help initiate the vortex at lower angles of attack, and make them more reliable at higher angles of attack.

You will find vortex generators on many aircraft, most notably the F18.

And also on a tuna in front of its main tail fin.