Spitfire Fin - Solo & PB Larry...

General Discussion
1

So there was a fin that caught my eye a couple months ago:

Because I’d been reading about tip drag etc. with all the talk about carbon hoops, Roy’s fins, Oneula’s Wavegrinder…

So Solo sent me this fin:

Made by Larry in this factory (see how many threads can come together?):

http://www.swaylocks.com/…orum.cgi?post=323606

And this is how I feel about it, after surfing it once in pretty nice south swell waves, about chest high…

OK Noel...

This fin can handle angles way beyond my abilities.

I put it all the way back in a box (that was already only 5" away from the tail) of a 10’1 longboard. Tail about 14", soft rails, tail rocker in an accelerated curve up to about 4". Its a composite board, only about 15 lb.

First wave I dropped into, I was 10’ behind a section. But before I even had a chance to adjust my feet, I was popping out onto the shoulder. Had to drop a big kick stall to keep from outrunning the wave altogether.

And it was much the same on the next dozen waves.

I’m not kidding around or blowing smoke because I spent money - it was really all that. Kick stalls were the norm, probably had to throw one on 4 out of every 5 waves I caught today. My buddy Michael was saying how fast I was squirting out from behind the sections. There was even this dreadlocked guy who’s always sitting inside, waiting to jump on when people can’t make the section, and he had to keep pulling back when he could see that I was going to make it.

If this is what reduced ( or no?) tip drag is all about, then I want more.

Its funny: I’m a beginner kiteboarder. With a kite & light wind, you have to learn that keeping the kite moving creates more ‘apparent wind’ for the leading edge of the kite, making it seem to fly faster and therefore, create more lift. This fin felt just like a kite - on the big waves (like high wind), I could trim it out, park it, and go light speed. On the mushier waves, if I kept it moving - sine waves up & down, just like a kite - it would push faster & faster. Other fins, when the waves mush, you can push them but at a certain point it becomes academic.

How many more can you make?

:slight_smile:

Thanks again

Ben

Edit: BTW, in case anyone was waiting for a review of the other fin combinations possible with that board… I’ve also tested the board twice with the Griff-type 5-fin setup, 4 equal 4" front & back side fins, and a 3" center. Its good off the bottom, faster & more stable in trim than I expected, rollercoasters nicely, but hangs up in the top of the wave a little, like it would rather hold a high line than hit high & come back down. Takes more effort than I thought it would to redirect downwards.

Next up (if I can bring myself to take out the Spitfire fin) is a quad, like Robin recommended (in the photo above), with the upright 4.5" fronts, raked 4" rears, so I can pivot off the fronts & drive off the back.

Now, all I need is some more waves. :slight_smile:

2

Benny, I am glade you like the fin design that Solosurfer came up with and I added the foil that I thought would suit Solo’s liking. But the Red fin is first generation with a thick leading edge foil that I thought would give the fiber glass fin the feel of the plastic Star Fin. After Solosurfer rode the fin a couple of times I wasn’t really satisfied with the answers he was giving me to my questions about the performance of the fin. So I tweaked the leading edge foil alittle more on the White fin you got which is the second generation of Solosurfer’s fin. Your responds is what I was hoping for after surfing the fin, because you got the second generation fins before Solosurfer did, his order of those just went out.

3
Quote:

Benny, I am glade you like the fin design that Solosurfer came up with and I added the foil that I thought would suit Solo’s liking. But the Red fin is first generation with a thick leading edge foil that I thought would give the fiber glass fin the feel of the plastic Star Fin. After Solosurfer rode the fin a couple of times I wasn’t really satisfied with the answers he was giving me to my questions about the performance of the fin. So I tweaked the leading edge foil alittle more on the White fin you got which is the second generation of Solosurfer’s fin. Your responds is what I was hoping for after surfing the fin, because you got the second generation fins before Solosurfer did, his order of those just went out.

Hi Larry…we know spitfire style fins are nothing new…but I wanted the good points of Cheyne’s winged keel without some of it’s fickle nature to tail rocker. Benny1…glad your enjoying your purchase. Try it in the Horan next. I am curious.

4

Exciting review, Benny! I want one–I have a nuggety shorty with soft rails in the tail I want to put it in, and switch out between it and a flex fin.

Noel, are those available yet?

Plans for sidebites with similar planshape?

greg

5
Quote:

Exciting review, Benny! I want one–I have a nuggety shorty with soft rails in the tail I want to put it in, and switch out between it and a flex fin.

Noel, are those available yet?

Plans for sidebites with similar planshape?

greg

Yes…I have four in stock now.

6

Mmm nice I have some boards to try that spitfire fin on too. Should we wait for 3rd generation? Benny I think the rear fins in the Quad setup in the pictures will be too bendy and be overpowered and without enough twang. I look forward to your review and to be proven wrong. How about some rear elipticals?I think they’re great fins for quads as the shape and the 1/4" glass works well together.

mark

7
Quote:

Mmm nice I have some boards to try that spitfire fin on too. Should we wait for 3rd generation? Benny I think the rear fins in the Quad setup in the pictures will be too bendy and be overpowered and without enough twang. I look forward to your review and to be proven wrong. How about some rear elipticals?I think they’re great fins for quads as the shape and the 1/4" glass works well together.

mark

I don’t know about third generations. The first worked fine, but has less drive. The second seems to be the ticket for all around, but like all things experimentation will continue. We have some small rear fins in the design coming out as well for multi fins.

8

I made these using a Spitfire concept, but with rake. The basic idea was to take a normal rake and make the chord lengths follow an elliptical progression. You end up with a very pointy tip if you do that and incredible release.

I think I’ve seen that solo spitfire fin template before outside Halcyon’s fin artists shop in Santa Cruz, but slightly different materials were used.

9

Blakestah that’s not at all like a spitfire fin.

The spitfire fin is so good precisely because it doesn’t have a sharp tip, and raking it extremely removes it even further from the concept, the spitfire fin has a trailing edge with reverse rake, the reverse rake on the trailing edge is important, as is the fact that the fin shape is generated using ellipses

.

10

Hi Mark, I don’t think there will be a third generation on this fin and there wouldn’t have been a second but I like to tweak things alittle before sending it to market. But Solosurfer had no problem with the first generation and probably would have not had a problem at all because he liked the fin. But if I am not completely satisfied with something I keep tweaking it until I like it and my customer has the best product to my knowledge. In this case I took it up on myself to send Benny something different than I made Solosurfer hoping that he would give feed back to Solosurfer before he got his order. If the second generation would have gotten bad feed back from Benny, I would have taken back the fins from Solosurfer and replaced them with the first generation. But my gut is usally right and this was one of those things I pushed ahead on. And to get a accurate answer I don’t always like letting people know whats going on because it takes away from finding out the true performance answer.This fin for what Solosurfer wants it to do is now done to both of our liking and different design sizes will start from this proven design on. Hope that answers your concerns.

11
Quote:
Blakestah that's not at all like a spitfire fin.

The spitfire fin is so good precisely because it doesn’t have a sharp tip, and raking it extremely removes it even further from the concept, the spitfire fin has a trailing edge with reverse rake, the reverse rake on the trailing edge is important, as is the fact that the fin shape is generated using ellipses

.

When I played with fin rake I found it to be a sensitive factor in fin design, and small deviations from the norm were not acceptable to many surfers.

So I started with the most common thruster fin rake in designing that fin. Fins have rake for reasons that are not relevant to airplanes like the Spitfire.

Then on the computer I played with the rear edge to make plots of chord length vs depth follow and elliptical profile (eg Spitfire wings). That fin I made is pretty dern close.

But I left the design behind, one of my test riders rode the board well but said he was scared the whole time because the fin tips were so pointy that every time he biffed or bailed all he could think of was the sharp tips nailing him. I’d ridden it hundreds of hours before that without incident. I updated the template to include enough fin tip to not poke someone’s eye out.

Its all fun and games until someone loses an eye, you know.

12

Benny, Since we are talking about Spitfire Plane, lets not forget the Famous Mustang. Here’s a fin I made in 1986 designed by Carl a Coarseboard sailor who worked for Hughes aircraft.

13

Benny, Here’s a few more different elliptical trailing edge designs.



14

Aloha WWMark:

I had a hard time detecting exactly what template it was in the photo but if it is the one I think it is then read on.

Actually experience has shown that the exact opposite is in fact true of the rear fins shown in the quad, they do not overflex and have a lot of drive and twang.

Over here in Hawaii I have done a lot of boards with a similar setup to this [only difference being that the front ellipitical is a cutaway version] and they have proven to be incredible in a quad setup. In fact, every multi-fin board I make uses this template in some form or another. They have been used in everything from 6’ fishes to 10’ guns! It is definitely one of my best selling fins.

My personal longboard is setup with these same fins and I have not experienced a situation where they are too bendy and they do have plenty of twang.

In fact, most of the thruster guns that I build are equiped with this exact same fin but a larger size, and if there is one place you don’t want them to be too bendy it is in large surf. The consensus is that they have a lot of drive and in fact do not over flex and have a lot of pop out of turns. They are also very fast!

This template is also used on 2+1 longboards as side bites and in that situation it has proven to be the case that they do not over flex, although in that setup they are only 4" tall. But the 4" is also what is used in the quad setup as the smaller fin.

So based on experience with a lot of boards your observation has not proven to be true.

Now of course as with everything in life there might be fin setups, waves, surfers, or boards that might make it feel like it is being over powered, but that could be any number of reason not the least being that the fin is to small. But for this particular fin [assuming it is the one I think it is] being to bendy is not an issue!

-Robin

15

Benny, Here’s a cut-away version of your Quad set-up by Robin done with carbon inlay that a customer from Peru brought me the carbon to make a special set for him using ProBox.



16

whoa, that is waaayyyy hot!

18

You Benny1,

IMHO what happened when you put the spitfire templated fin on you 10 footer is this: You minimized fin drag enormously. You allowed the rails, rocker and bottom configuration on the board to work the way they were intended to by the shaper. With little or no turbulence coming off the center of the board the board is more alive than it has ever been before. Thus the board itself was more engaged with the water than it has ever been and there is at the same time creating less turbulence along its laminar flow. You fortunately hit just the right spot to compliment the board config. with fin placement and with no release drag what- ever your board will change directions as freely as one could ever hope it to. As far as board speed goes you’ve fully maximized trim speed and so the board is making sections now that it couldn’t before because your at the top of it’s straight line speed potential.

Well foiled fins that compliment a board’s foil placed properly make all the difference. The spitfire outline causes a little disturbance as it passes through a fluid as any out there. Less turbulence means more centripetal energy.

No Worries, Rich

19
Quote:

You Benny1,

IMHO what happened when you put the spitfire templated fin on you 10 footer is this: You minimized fin drag enormously. You allowed the rails, rocker and bottom configuration on the board to work the way they were intended to by the shaper. With little or no turbulence coming off the center of the board the board is more alive than it has ever been before. Thus the board itself was more engaged with the water than it has ever been and there is at the same time creating less turbulence along its laminar flow. You fortunately hit just the right spot to compliment the board config. with fin placement and with no release drag what- ever your board will change directions as freely as one could ever hope it to. As far as board speed goes you’ve fully maximized trim speed and so the board is making sections now that it couldn’t before because your at the top of it’s straight line speed potential.

Well foiled fins that compliment a board’s foil placed properly make all the difference. The spitfire outline causes a little disturbance as it passes through a fluid as any out there. Less turbulence means more centripetal energy.

No Worries, Rich

Hi Rich…glad you posted.

20

Wow. That is a GOOD post. Never thought much about the turbs off a single affecting the tailward rail’s release (EDIT: and the tail’s planing). Really amazing.