The reason I prefer brass barrel nuts is so they WILL strip under extreme circumstances. This will ensure that the fin box, the rear of the board and half the carbon underlay will stay attached to the rest of the board if I hit a rock, fish, whatever. $250 fin or $2500 board, the choice is yours.
Just had a great hit out with the 28 in the conditions that it was designed for. Flat water and weed. The fin performed perfectly, I could cut through all the surface weed with no issues and it handled the chop with ease. Maxed out on the 7.7 and although the fin was designed to get going in the light stuff it's no slouch at going fast. Well done Fangy , this fin likes Lake George 
Select to expand quotekato said..
Just had a great hit out with the 28 in the conditions that it was designed for. Flat water and weed. The fin performed perfectly, I could cut through all the surface weed with no issues and it handled the chop with ease. Maxed out on the 7.7 and although the fin was designed to get going in the light stuff it's no slouch at going fast. Well done Fangy , this fin likes Lake George
Good to hear Kato, thank you for taking the time to post and I am very pleased to see smiles on the dial.
I suspect it's not just the fin that loves LG!
Well Craig you certainly took up the challenge, beat Fangy's prediction by almost 4 kts
i had a lot of fun with the 21 speed and the original 20 cut to 17. Pushed them hard also in small chop and they never let go. Sue has tried the 18 Budgi special that is now with Andrew and I might give it a go soon.
Select to expand quotepowersloshin said..
i had a lot of fun with the 21 speed and the original 20 cut to 17. Pushed them hard also in small chop and they never let go. Sue has tried the 18 Budgi special that is now with Andrew and I might give it a go soon.
Good to see you made it to LG buddy! I was worried the border closures would keep you at home. Please be careful on that FF18 Budgie, it's not as friendly as it's siblings and I would hate to see a trip cut short due to a bad crash.
Im glad I only read that warning now after using it twice.
First use I thought it was a 21cm..Lucky as I was using it on a 90ltre ( 59?), with a 6.2m sail.If I'd realised how small it was I would have been too focused on possible problems..
6 " chop. Powered but not fully and the wind was a bit patchy.
I was careful with it, not stomping on it like I do my 21.5cm cutdown 24cm. I noticed it felt a bit slidey at times and it spun out once but it wasn't too bad to get back in. I just sheeted out a bit and bore off.
Got a better 2 sec than I think I would have got with the cutdown.
The 2nd go was in 15 - 22kts powered conditions in 4 - 6 " chop and I almost PBd my hr despite sailing into lulls and coming off the plane 4 times.
The 5th time I fell in due to no wind but held the sail up and managed to waterstart after a short wait.??
So no real control issues. It gets me upwind ok and it's faster..
You do need to be bit more careful with it to avoid spinout but no big deal.
I'm very spinout intolerant..A few experiences and I'll bin a fin..
The wind down here is much more consistent than at Budgy so the real test will be there.
Select to expand quotesboardcrazy said..
Im glad I only read that warning now after using it twice.
First use I thought it was a 21cm..Lucky as I was using it on a 90ltre ( 59?), with a 6.2m sail.If I'd realised how small it was I would have been too focused on possible problems..
6 " chop. Powered but not fully and the wind was a bit patchy.
I was careful with it, not stomping on it like I do my 21.5cm cutdown 24cm. I noticed it felt a bit slidey at times and it spun out once but it wasn't too bad to get back in. I just sheeted out a bit and bore off.
Got a better 2 sec than I think I would have got with the cutdown.
The 2nd go was in 15 - 22kts powered conditions in 4 - 6 " chop and I almost PBd my hr despite sailing into lulls and coming off the plane 4 times.
The 5th time I fell in due to no wind but held the sail up and managed to waterstart after a short wait.??
So no real control issues. It gets me upwind ok and it's faster..
You do need to be bit more careful with it to avoid spinout but no big deal.
I'm very spinout intolerant..A few experiences and I'll bin a fin..
The wind down here is much more consistent than at Budgy so the real test will be there.
Oops sorry Sue I somehow missed your GPSTC post - found it now :-) I am very pleased to hear you have had some success with the fin and many thanks for the feedback on board/sail combinations. As you have no doubt noticed, it's a much finer fin than your cutdown 24, so although I would expect it to be substantially quicker, it is good to note that you managed some uphill stuff without too much drama. I hope LG keeps delivering for you lucky mob!
First go of the budgy 18 yesterday. JP 70 litres and KA5.7 speed. Wind up to 25 knts, so I was never overpowered. The fin slices through the weed like if it wasn't there, I had fun going over the weedbergs with foam toppings while everyone else was going around them.
I pushed it hard to go upwind also in the small chop and never spun out and was thinking 'what do I need to do to make it spin out ??'
Speedwise it feels fast , I did 35.1 that is about 1/2 knot faster that I did with same gear and the ff20 cut to 17 a few days ago.
Andrew Haigh also tried the fin in lighter winds and found that it does not spin out.
Today will be another good day, might try it with the patrik 95 to compare to the speed 21 or try and find other volunteer testers
Select to expand quotepowersloshin said..
First go of the budgy 18 yesterday. JP 70 litres and KA5.7 speed. Wind up to 25 knts, so I was never overpowered. The fin slices through the weed like if it wasn't there, I had fun going over the weedbergs with foam toppings while everyone else was going around them.
I pushed it hard to go upwind also in the small chop and never spun out and was thinking 'what do I need to do to make it spin out ??'
Speedwise it feels fast , I did 35.1 that is about 1/2 knot faster that I did with same gear and the ff20 cut to 17 a few days ago.
Andrew Haigh also tried the fin in lighter winds and found that it does not spin out.
Today will be another good day, might try it with the patrik 95 to compare to the speed 21 or try and find other volunteer testers
Well that's exciting news for a Monday morning! I was very worried about the spin-out in chop scenario, so I am very happy to hear you went well G! I am super keen to hear any more comparisons with your cut down FF20 or FF21Speed, and any suggestions for design modifications. I think LG might be very kind to fins and perhaps as Sue has already said, the real test will be Budgewoi itself. But in the meantime, fingers crossed there are some more good sessions to come.
Yesterday tried the budgy 18 with Patric95 (62 wide) and Koncept 6.6. Compared to the Speed 21 needs a bit more care to go upwind in the chop, cannot push the back leg as hard, but need to push my weight in the harness as far forward as possible instead. Did not have enough wind to do bearaways, so cannot really comment speedwise.
I really cannot think of anything wrong with this fin or ways to improve it, will try and find others willing to test it
I used my 21s cut to 18 yesterday at Albany on a mistral 95 speed and 6.2 Koncept. There was a good breeze but not real strong, 20-25max my 2sec was 35.9 and 5x10 was 34.4 and nm was 32.9 Not fast but within two to three knots of the quick guys like Woody, Hardie, Ant, Cam and Elmo so for me ok for the day.
Upwind the fin was good, one spinout due to lack of concentration on my part otherwise no probs. The same downwind, the fin is predictable and the one spinout I had in the rough stuff going downwind in the low 30s was recoverable with a couple of bunny hops. There was a lot of weed close to the surface so the smaller the better as far as a fin went. I spoke to the other sailors on all types of fins ranging from 22 down to 16s and all that spoke to said they were experiencing occasional spinouts. I also managed to hit something without driving the fin up into the finbox which is a dead cert in a normal fin. I confess I haven't used my 20 fangy much and that was the go-to fin for the locals Evets and Morts yesterday.
Select to expand quotepowersloshin said..
Yesterday tried the budgy 18 with Patric95 (62 wide) and Koncept 6.6. Compared to the Speed 21 needs a bit more care to go upwind in the chop, cannot push the back leg as hard, but need to push my weight in the harness as far forward as possible instead. Did not have enough wind to do bearaways, so cannot really comment speedwise.
I really cannot think of anything wrong with this fin or ways to improve it, will try and find others willing to test it
A big Thank You for your help Powersloshin (and to everyone else who has been prepared to do some testing for me) Given it's such a fine and short foil, the lifting performance is pretty much as expected - the trade-off hopefully being less drag at higher speeds and good manners in the process, so fingers crossed there is a big wind day on your way soon!
Select to expand quotewaricle said..
I used my 21s cut to 18 yesterday at Albany on a mistral 95 speed and 6.2 Koncept. There was a good breeze but not real strong, 20-25max my 2sec was 35.9 and 5x10 was 34.4 and nm was 32.9 Not fast but within two to three knots of the quick guys like Woody, Hardie, Ant, Cam and Elmo so for me ok for the day.
Upwind the fin was good, one spinout due to lack of concentration on my part otherwise no probs. The same downwind, the fin is predictable and the one spinout I had in the rough stuff going downwind in the low 30s was recoverable with a couple of bunny hops. There was a lot of weed close to the surface so the smaller the better as far as a fin went. I spoke to the other sailors on all types of fins ranging from 22 down to 16s and all that spoke to said they were experiencing occasional spinouts. I also managed to hit something without driving the fin up into the finbox which is a dead cert in a normal fin. I confess I haven't used my 20 fangy much and that was the go-to fin for the locals Evets and Morts yesterday.
I suppose cutting down a FF21 Speed is always going to be the alternative as we know that's a 40plus fin. Can someone please organise some heavy weed at my local so I can put the two back to back and compare the Budgie18 vs a cutdown FF21Speed in the thick stuff?
(and quietly, I must confess that i really like the FF20 - I think it's my favourite fin)
Select to expand quotekato said..
Opps.....now 37.8 for the Fangy 28. I now recon it will do 40
I have a day to try and figure this one out...and I still can't believe a FF 28 doing almost 38! I know the customising tweaks would have made it quicker, but not that much. It also is a bit deflating - I always was pretty chuffed with myself when I got into the low 30's on mine. Now it seems I was setting myself a very low bar. So instead of accepting that I might have to try harder, I have decided that the result is down to Kato being really freaky good at this gig.
Select to expand quotefangman said..kato said..
Opps.....now 37.8 for the Fangy 28. I now recon it will do 40
I have a day to try and figure this one out...and I still can't believe a FF 28 doing almost 38! I know the customising tweaks would have made it quicker, but not that much. It also is a bit deflating - I always was pretty chuffed with myself when I got into the low 30's on mine. Now it seems I was setting myself a very low bar. So instead of accepting that I might have to try harder, I have decided that the result is down to Kato being really freaky good at this gig.
Ross, what you are not taking into account is how amazing the water conditions are at LG this year. You can get mirror smooth water in up to 20kts.
Select to expand quoteJohn340 said..fangman said..kato said..
Opps.....now 37.8 for the Fangy 28. I now recon it will do 40
I have a day to try and figure this one out...and I still can't believe a FF 28 doing almost 38! I know the customising tweaks would have made it quicker, but not that much. It also is a bit deflating - I always was pretty chuffed with myself when I got into the low 30's on mine. Now it seems I was setting myself a very low bar. So instead of accepting that I might have to try harder, I have decided that the result is down to Kato being really freaky good at this gig.
Ross, what you are not taking into account is how amazing the water conditions are at LG this year. You can get mirror smooth water in up to 20kts.
I have tortured myself with too many of Daffy's and others video's already - but yes John, it looks sensational alright! But I still have this feeling a FF28 at 38 knots is like using a B-52 to break the sound barrier!
Select to expand quotekato said..
Opps.....now 37.8 for the Fangy 28. I now recon it will do 40
Wow , is that in standard trim ?
A standard Fangy 26 has more than enough grip for a big board , big pilot 8 m sail.
Select to expand quoteImax1 said..kato said..
Opps.....now 37.8 for the Fangy 28. I now recon it will do 40
Wow , is that in standard trim ?
No Imax, I customised it a bit to reduce the lift and drag. Pictures bag on Page 10 of this thread, side by side with a standard FF28 so you can see the differences.
I've been thinking too. The water state wasn't bad but not flat as we have had. The wind wasn't strong but a squall came through and I thought stuff this I'm changing down and came off the wind to get back to the cars as the extra wind hit. As I went further off the wind I got more of a push . This then convinced me to try harder as the board had settled. I'll put it down to having the right gust at the right time with the right equipment. Couldn't get anymore than a 34 out of the same combo today despite having better consistent wind. I love that I can use this fin to get going in 6-8 kts with a 9mt and still do a 38 kt peak. Great fin design. I think Liptons would be perfect for a 40 on this combo too.
On The Flow Characteristics of Non-Slender Delta Wings.
This post gets a bit nerdy with low levels of hyperbole, so to avoid getting a headache, simply read the next sentence and then click back to The Funny Images thread. On a FF make sure your leading edges are well rounded, not sharp.
For the keen masochists: Kato's recent almost inexplicable efforts on an FF28 gave me a reason to revisit the research on non-slender delta wings to search for an explanation. Specifically, the differences between true slender winged deltas and the non-slender delta wings*. I found some good info with investigations done at Reynolds** number in the order of 10^6, this being the range in which windsurfing fins operate. I was lucky enough to be able to make contact with all three authors of the paper below (one of whom is a keen windsurfer!) and they were all extremely generous with their time and thoughts as to the extrapolation of their findings to the behavior of FangyFins.
[JOURNAL OF AIRCRAFT,Vol. 54, No. 2, March-April 2017. Numerical Investigations of Vortical Flow on Swept Wings with Round Leading Edges by Andreas Schutte]
* A non-slender delta is generally regarded as one with a rake less than 60 degrees. ** Reynolds number helps predict flow patterns in different fluid flow situations and is based upon calculations of incompressible flows varying viscosity and velocity. Fun fact - Air traveling at below 100 metres per second is regarded as incompressible! 
An illustration of vortical flows from Schutte's paper.
To summarise the research, under the right conditions, the non-slender delta wing has an attached leading-edge vortex, and possible secondary and tertiary vortices depending on the leading edge radius and the curvature of the leading edge. These vortices tend to not interact directly with the wing surface downstream, unlike a slender delta and the hydrodynamics may be more stable as a result. However, these only develop when the ratio of leading-edge radius to chord length is less than 0.005. e.g. if you have a chord length of 200mm, the radius of the leading edge will be 1mm.
I noted that a small radius leading edge creates less drag at low angles of attack and conversely, at higher angles of attack, the small radius is more efficient at triggering the vortex flow and produces a more intense pressure gradient than its blunter siblings.
Ideally, I wanted to create a leading-edge with both advantages, one nicely rounded to give attached flow, low-speed lift, and move the vortex away from the board - fin junction pressure wave region. The other a really fine radius to give lift at speed with less drag. Now, whereabouts along the leading edge do I transition from one to the other?
Evolutionary clues on slender delta wings belong to the Swift and I felt this was as good a starting point as any. I copied the layout of a Swift wing as far as having a broad shoulder and arm region, with a rapid transition to the fine radii of the finger region. 
In practice, the ability to refine the leading edge radius to a ratio of 0.005 is limited by the desire to ensure the edge is safe to the user, equipment, and environment and not act as a knife. In relative terms, this meant the ratio was initially large at the root, decreased at the transition zone, and then slowly increased toward the tip due to the decreased chord width span-wise. Schutte's studies indicated that a small but increasing ratio toward the tip was not significant.
[ Schutte found that within the parameters he studied, increasing wing sweep, increasing leading-edge radius, and decreasing Angle of attack all promoted attached flow on non-slender delta wings] 
The test fin was an FF24. I tested two leading-edge transitions from large to small radii signs. One with the transition complete by about 25% and the other at approximately 50% along the leading edge from the root. The preliminary results from on water were a perception of
a decrease in all-round ability, partially offset by improved top-end speed, with both parameters proportional to the length of small radii leading edge.
My initial conclusions:
At the relatively low angles of attack used in windsurfing, the vortex lift flows are not a large enough component of the overall lift to be considered a major influence in design.
The physical limitations of achieving small edge radii are such that the amount of the fin leading edge meeting the required physical parameters is relatively small, and therefore any attempt to harness vortical flow is unlikely to be a worthwhile pursuit. (Except perhaps on the FF28 where the dimensions are such that the above conditions can be met over a greater length of the leading edge)
Appendix: A rough formula for calculating the least leading edge radius ratio to ensure attached flow is : LE Radius ratio = 1.12 x t^2 [where, t = maximum thickness as fraction of chord.] Example: On an 8% foil with a chord of 200mm The LE radius ratio = 1.12 x (0.08)^2 => 0.007 (approx) Therefore: Chord length of 200 x LE ratio 0.007 = 1.4mm radius LE required
Parting thoughts:
Interestingly if you do this calculation with a 7% chord thickness foil, the ratio is approx 0.005. On my fins, I find 7% an unstable fin, and I wonder that is due somewhat to the initial vortical flows developing on the fin. Thoughts anyone?
Select to expand quotefangman said..
....Thoughts anyone?
I'm so happy I don't have to study all this to enjoy the results !
btw I still have the budgi special with me, waiting for a day with decent wind to go up
Select to expand quotepowersloshin said
I'm so happy I don't have to study all this to enjoy the results !
I enjoy the process. And because the measurements and calculations are all in metric I know I will keep Imax happy regardless of the results!
Oops, I just realised, I forgot to mention the effect on board trim. The smaller radii leading-edge noticeably reduces the upward thrust (vertical drag vector component) from the fin and so the board rides on the tail with a greater nose-up attitude. It appears that most of the trim affecting upward thrust is from the tip end 50% of the fin because both versions ride tail heavy/nose up compared to the original. How much of this is due to the slightly greater torque moment around the rotional centre of the board at the tip end of the leading edge versus reduced tip vortex drag or both, I have no idea.
Take home message: reducing the leading edge radius in the tip half will allow you to move your mast foot forward if needed to improve trim.
I have had only a couple of sessions sailing with the Fangy Fin. Once with a really rough 80 grit finish that I spent no longer than a minute doing. Sailed really well in moderate chop with no sign of spinout and was super happy with it. Finished to 1200 Grit and had another session with more wind and very flat water with same kit. Fin didn't feel as stable somehow, take that with a pinch of salt as I have relatively low experience. Having a complete absence of any wind lately I decided to polish and Anodise the fin. This is against all practical advice from Fangy himself saying that above 400 grit there has been little observation of improvement. I thought I'd share the result as in case anyone else is thinking of doing the same. The result was not great. You can see I was a bit too enthusiastic with my sanding on the first pass chasing some porosity which probably will adversely effect the fins performance. I did this Anodising twice as the first attempt I thought I had failed to clean the fin sufficiently and had left some polish residue which caused what you see here. So I stripped the anodised layer, reground with 80 grit then all the way back to 2000 grit and then polish. It didn't shine as well on the second attempt. This 2nd attempt I took great care cleaning prior to starting the anodising but made negligible difference to the end result (maybe worse even). Most probably because there is slight porosity in the fin which is enlarged in the caustic step and then really brought to light in the dye step. The poor fin had suffered 3 trips to the caustic bath by this stage. In hindsight, it doesn't appear to be worth anodising the fin, or, at least skipping the dye step as the result looked very good just prior to dropping into the dye tank. Certainly don't attempt it twice like me. I made a quick video of the process which was quite fun and now at least I am set up to Anodise forever. Due to the amount of sanding I am pretty sure I have changed the profile enough that it won't handle anywhere near original but will have to wait for some wind to find out. I also took it down to a company I used before that does metal spraying to see if they could fill the porosity prior to sanding. Sure they could, but the cost exceed the fin cost by double so seemed little point. Since I'm new here the photos or links may not work so I will post them later if that is the case. Video of the process
I think Mal Wright said a full polish can be a problem on a non perfect foil, without a small boundary layer, there can be flow detachment. it's safer to stop at 600grit.
