Forums > Windsurfing   Gps and Speed talk

FangyFin 18 V2Speed - The Budgie special is off the drawing board!

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Created by fangman > 9 months ago, 19 Sep 2020
fangman
WA, 1238 posts
19 Sep 2020 3:44PM
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After lots of emails and discussions with weedy spot locals, the FF18 Budgie has left the drawing board. I tried to cover as many bases as possible as far as the requirements for individual sailors and locations were concerned and adapted the design to make customisation easier.
The fin is designed for shallow water and very thick weed typical of vintage super weedy seasons at Budgie, LG, and Mandurah. The handling characteristics are skewed toward speed rather than upwind ability or rough water handling.



The fin will be cast aluminium in order to provide the superior durability required when faced with abrasive weed, touchdowns, razorfish and general user abuse. It is designed at 18cm, but with casting shrinkage and finishing it will is likely to be 17 something. The weight will be similar to the same fin made in G10, but obviously far tougher.
The main points by comparison with the FF21Speed are:
- The foil and fillet are adapted from the FF21Speed.
- The box base design is slightly thicker and longer.
- The base section has drilling guides for bolt hole position and the correct angulations imprinted on the side to make it easier for DIYers (and me) to get this critical part smack on the money.
- The surface area is increased to provide resistance for larger sails in lighter conditions.
- The frontal area is reduced with an even more highly swept rake in the tip half.
The fin has been designed hollow, but given the difficulties and added costs in casting the hollow for the sake of shedding a few grams, the production model hollow will be smaller than pictured, if at all.

Next stop, off to Nebbian to get it printed and then to the foundry for a couple of jobber pattern test fins. I will prep those and send them across to Budgewoi and let the real testing begin!

powersloshin
NSW, 1654 posts
20 Sep 2020 6:38AM
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Unleash the beast !!

kato
VIC, 3340 posts
20 Sep 2020 9:58AM
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Select to expand quote
fangman said..
After lots of emails and discussions with weedy spot locals, the FF18 Budgie has left the drawing board. I tried to cover as many bases as possible as far as the requirements for individual sailors and locations were concerned and adapted the design to make customisation easier.
The fin is designed for shallow water and very thick weed typical of vintage super weedy seasons at Budgie, LG, and Mandurah. The handling characteristics are skewed toward speed rather than upwind ability or rough water handling.



The fin will be cast aluminium in order to provide the superior durability required when faced with abrasive weed, touchdowns, razorfish and general user abuse. It is designed at 18cm, but with casting shrinkage and finishing it will is likely to be 17 something. The weight will be similar to the same fin made in G10, but obviously far tougher.
The main points by comparison with the FF21Speed are:
- The foil and fillet are adapted from the FF21Speed.
- The box base design is slightly thicker and longer.
- The base section has drilling guides for bolt hole position and the correct angulations imprinted on the side to make it easier for DIYers (and me) to get this critical part smack on the money.
- The surface area is increased to provide resistance for larger sails in lighter conditions.
- The frontal area is reduced with an even more highly swept rake in the tip half.
The fin has been designed hollow, but given the difficulties and added costs in casting the hollow for the sake of shedding a few grams, the production model hollow will be smaller than pictured, if at all.

Next stop, off to Nebbian to get it printed and then to the foundry for a couple of jobber pattern test fins. I will prep those and send them across to Budgewoi and let the real testing begin!


Do you sleep?
Nice work

fangman
WA, 1238 posts
20 Sep 2020 1:57PM
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I have no units at Uni this semester Kato, so I have to keep my brain busy doing something

waterbouy101
NSW, 42 posts
28 Sep 2020 9:47PM
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Hey where can we buy these fins?


thanks

fangman
WA, 1238 posts
28 Sep 2020 8:16PM
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waterbouy101 said..
Hey where can we buy these fins?


thanks


pm'd you Waterbuoy101.

At this stage Nebbian had the files and hopefully printing as we speak. After that is complete, then off to the Fred at the foundry for a couple of jobber pattern test fins. I will prep those and send them across to Budgewoi and let the real testing begin!

fangman
WA, 1238 posts
24 Oct 2020 10:08AM
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Nebs has finished the 3D printing and has produced another Batman worthy addition to the team. Now it's off to the foundry for Fred to knock out a few jobber pattern trial fins.





Imax1
QLD, 4527 posts
24 Oct 2020 4:19PM
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Why do the fins come in two halves , easier storage ?

fangman
WA, 1238 posts
24 Oct 2020 5:21PM
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Imax1 said..
Why do the fins come in two halves , easier storage ?


The 3d printers have a maximum size envelope limitation. (varies with each printer). I am guessing Nebs sectioned the fin to not only fit it into the printer efficiently, but also provide the most structurally stable pieces that could then be easily joined.

Rodskeg
NSW, 102 posts
25 Oct 2020 12:15PM
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I'm keen on getting one please mate, I head up to Budgy regularly and would like something other than a MUF Delta for a change

fangman
WA, 1238 posts
25 Oct 2020 10:18AM
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Rodskeg said..
I'm keen on getting one please mate, I head up to Budgy regularly and would like something other than a MUF Delta for a change


Hey Rodskeg, I am getting 2 trial fins cast up in the coming weeks and then I will send one across to Budgewoi for testing asap. If the fin gets the thumbs up from the resident crash testers, I will have a casting pattern constructed and cast up a 'proper sized' batch.

decrepit
WA, 11828 posts
25 Oct 2020 11:53AM
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Rodskeg said..
I'm keen on getting one please mate, I head up to Budgy regularly and would like something other than a MUF Delta for a change


You'll certainly notice a big difference from the delta

kato
VIC, 3340 posts
25 Oct 2020 6:33PM
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Just a slight side note, I got the FF 28 "Kato V" to a 31 ,2 sec. Not to bad for a fin designed to get me planning early. Love ya work Ross

fangman
WA, 1238 posts
25 Oct 2020 8:38PM
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kato said..
Just a slight side note, I got the FF 28 "Kato V" to a 31 ,2 sec. Not to bad for a fin designed to get me planning early. Love ya work Ross



Crikey Kato! That's bloody good going on an FF28! I think those mods might have been effective.

powersloshin
NSW, 1654 posts
26 Oct 2020 6:33AM
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Yes I agree, can you put Kato on my fin too !!

fangman
WA, 1238 posts
29 Nov 2020 11:05AM
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Photos and prep by Waricle. As you can see, Peter is pretty damn good at making metal shiny!

We haven't had a chance to test this one properly yet. Initial quick impression is that it's slippery but not as well behaved as its siblings in chop. A bit more testing on a decent breeze, and low tide weed will give us an indication of its overall performance.








sailquik
VIC, 6068 posts
29 Nov 2020 4:50PM
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Wow! That looks a lot thinner than previous Fangy Fins!

fangman
WA, 1238 posts
30 Nov 2020 7:43PM
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sailquik said..
Wow! That looks a lot thinner than previous Fangy Fins!




Well spotted Daffy, certainly it has been to Weight Watchers to deal with the waistline. Peter and I are experimenting with the leading edge radii to improve the chop handling, but with less than 18cms to work with, there is a limit to what we can achieve. The thicker rounded leading edge on a delta wing will shift the first leading edge vortex away from the root area and hopefully less likely to interact and contribute to a cavitated low pressure side and spin out. The pay off is the leading edge vortex pressure overall is less strong and thus provides less lift. The trailing edge of the fin has to therefore be extended to provide enough surface area for the initial weaker vortices to act upon. Further down the leading edge it can trend toward a sharper edge which in turn trips and initiates a stronger leading edge primary vortex albeit acting over less wing area. Gees that got nerdy quickly. Sorry peeps.
Pic shows a more rounded edge as opposed to the photos above.


fangman
WA, 1238 posts
2 Dec 2020 7:32PM
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The FF18 Budgewoi special is leaving today on its trek east. The fin is a prototype only. Powersloshin will be the keeper of the fin, but it is free for all to have a belt around. We have not done extensive tests yet - so far it's quick and some minor mods have improved its flightiness when faced with chop. We need much more info to decide what mods to make before committing to a final set of patterns and attempting to introduce a internal hollow









tbwonder
NSW, 639 posts
2 Dec 2020 10:54PM
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Ross, the new fin looks great. I am very keen to give it a go, if I can borrow it from Powersloshin.

fangman
WA, 1238 posts
2 Dec 2020 10:07PM
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tbwonder said..
Ross, the new fin looks great. I am very keen to give it a go, if I can borrow it from Powersloshin.


Just bribe him with cake, that seems to work
Just beware, it's still a test fin so it there may be some surprises until we get it all vices ironed out (hopefully by LG pilgrimage season!).

Imax1
QLD, 4527 posts
3 Dec 2020 6:52AM
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What's the fastest a standard FF28 done ?
What could a hack like me realistically expect ?

fangman
WA, 1238 posts
3 Dec 2020 8:16AM
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I don't know the record for the FF28. Personally I have done 33.something on my Xantos 310, but that would have been on excellent water etc. I think if you are heavy enough to hold the fin down, then around the thirty mark is a good session indeed - but the brute force required to keep the basket under the balloon, and board trimmed flat, I find it's very tiring. Exhilarating but exhausting.
Col, I am usually too lazy to follow my to follow my own advice, but if you are regularly getting 30's, it's probably windy enough to change down to a smaller FKD FF combo. Just sayin', we haven't had the miniFKD board build thread yet....

fangman
WA, 1238 posts
28 Jul 2021 12:50PM
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FF18 Budgewoi Special V4. (...and an exclusive ' Limited Edition Low Hyperbole' SB post from me)
The latest design to hit Fred's foundry soon is the result of feedback from the dedicated crash test dummies on our eastern shores. The fin is a complete re-design of the existing FF18V2. Time will tell whether I have got it wrong and it is an anchor, or if it lives up to the design aims; to produce the lowest drag concomitant with benign handling. There is enough displacement ( high pressure side) lift to allow dogging up to the top mark and thereafter it is a slippery AF shape that can handle less than ideal conditions. Accordingly, the maximum performance efficiency occurs at very low angles of attack.



The fin has a number of anti cavitation strategies borrowed from maritime propellor research and design. The design intent is that the large radius and elliptical planform leading edge will delay leading edge cavitation, while a very long roof area and a maximum low pressure point well behind the mid chord line will further delay sheet cavitation. The foil profile design is less susceptible to surface area roughness effects than the previous FangyFins. This is to give greater flexibility of finish to those who wish to do the finishing themselves and provide a fin that only needs to be treated with a modicum of seasonal care and maintenance whilst still maintaining performance.

The location of the maximum thickness aft, decreases the velocity gradient (and hence the pressure gradient) in the mid-chord region. The resultant favourable pressure gradient in the mid-chord region promotes boundary-layer stability and increases the possibility that the boundary layer remains laminar. Laminar boundary layers produce less skin-friction drag than turbulent boundary layers but are also more likely to separate under the influence of an adverse pressure gradient. However, it is accepted that with Reynolds numbers to the order of 10^6 at the intended operating speeds, the flow is likely to transition from laminar flow irrespective of the design features.




Despite maximum chord thickness located well aft, viscosity effects may trigger cavitation bubbles in the flow separation zone behind the maximum chord thickness. The progression of these bubbles toward the leading edge and resultant sheet cavitation is hopefully retarded by the above strategies.

There is a small section of tip roughness to interfere with tip rollup and vortex formation. (Not shown on drawings) This further reduces the efficiency of the fin, but is an effective measure in countering the downstream tip vortex bubble migrating on to the foil and initiating sheet cavitation.

On a stream-lined body, with increasing velocity, pressure (form) drag increases with the square of the chord thickness, whereas friction drag (surface area) decreases as a proportion of total drag. Accordingly, the chord thickness is reduced to minimise form drag, but the surface area has been increased to provide adequate lift at low speeds.

The fillet has a varying radius that has been largely copied from America's Cup strut/foil designs and has proven effective in previous FF prototypes.





The base section is minimised as per the FF18V2 to take advantage of the fillet loading and drill guides for bolt placement incorporated in the casting. The base has been moved rearward a little more to offset the aft movement of the peak low pressure point with the foil change. The model number is now imprinted to make identification easier.

Well done all you dedicated scrollers! You got to the bottom of the page and discovered there really was a paucity of adjectives to be found. In any case, once I have a 3DPrint and casting it will be hitting the water. Stay tuned for whether I have created a lemon or something a little more tasty.





sboardcrazy
NSW, 7917 posts
28 Jul 2021 3:21PM
Thumbs Up

Select to expand quote
fangman said..
FF18 Budgewoi Special V4. (...and an exclusive ' Limited Edition Low Hyperbole' SB post from me)
The latest design to hit Fred's foundry soon is the result of feedback from the dedicated crash test dummies on our eastern shores. The fin is a complete re-design of the existing FF18V2. Time will tell whether I have got it wrong and it is an anchor, or if it lives up to the design aims; to produce the lowest drag concomitant with benign handling. There is enough displacement ( high pressure side) lift to allow dogging up to the top mark and thereafter it is a slippery AF shape that can handle less than ideal conditions. Accordingly, the maximum performance efficiency occurs at very low angles of attack.



The fin has a number of anti cavitation strategies borrowed from maritime propellor research and design. The design intent is that the large radius and elliptical planform leading edge will delay leading edge cavitation, while a very long roof area and a maximum low pressure point well behind the mid chord line will further delay sheet cavitation. The foil profile design is less susceptible to surface area roughness effects than the previous FangyFins. This is to give greater flexibility of finish to those who wish to do the finishing themselves and provide a fin that only needs to be treated with a modicum of seasonal care and maintenance whilst still maintaining performance.

The location of the maximum thickness aft, decreases the velocity gradient (and hence the pressure gradient) in the mid-chord region. The resultant favourable pressure gradient in the mid-chord region promotes boundary-layer stability and increases the possibility that the boundary layer remains laminar. Laminar boundary layers produce less skin-friction drag than turbulent boundary layers but are also more likely to separate under the influence of an adverse pressure gradient. However, it is accepted that with Reynolds numbers to the order of 10^6 at the intended operating speeds, the flow is likely to transition from laminar flow irrespective of the design features.




Despite maximum chord thickness located well aft, viscosity effects may trigger cavitation bubbles in the flow separation zone behind the maximum chord thickness. The progression of these bubbles toward the leading edge and resultant sheet cavitation is hopefully retarded by the above strategies.

There is a small section of tip roughness to interfere with tip rollup and vortex formation. (Not shown on drawings) This further reduces the efficiency of the fin, but is an effective measure in countering the downstream tip vortex bubble migrating on to the foil and initiating sheet cavitation.

On a stream-lined body, with increasing velocity, pressure (form) drag increases with the square of the chord thickness, whereas friction drag (surface area) decreases as a proportion of total drag. Accordingly, the chord thickness is reduced to minimise form drag, but the surface area has been increased to provide adequate lift at low speeds.

The fillet has a varying radius that has been largely copied from America's Cup strut/foil designs and has proven effective in previous FF prototypes.





The base section is minimised as per the FF18V2 to take advantage of the fillet loading and drill guides for bolt placement incorporated in the casting. The base has been moved rearward a little more to offset the aft movement of the peak low pressure point with the foil change. The model number is now imprinted to make identification easier.

Well done all you dedicated scrollers! You got to the bottom of the page and discovered there really was a paucity of adjectives to be found. In any case, once I have a 3DPrint and casting it will be hitting the water. Stay tuned for whether I have created a lemon or something a little more tasty.






I would have liked to try it at Budgy but Budgy is in Lockdown for us atm..

kato
VIC, 3340 posts
28 Jul 2021 6:05PM
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Great to hear that ya still thinking about that next step Ross. Still hoping for a 40 with the 28

powersloshin
NSW, 1654 posts
29 Jul 2021 7:15AM
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Sue, Andrew has the prototype, if you find another place to sail , you can get it from him.
Ross, maybe I am a bit lighter than Andrew, but I found the one I tested was perfect for me at LG. Not tried in budgi, but conditions are similar with floating weed a bit thicker in some places.

fangman
WA, 1238 posts
29 Jul 2021 9:07AM
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powersloshin said..
Sue, Andrew has the prototype, if you find another place to sail , you can get it from him.
Ross, maybe I am a bit lighter than Andrew, but I found the one I tested was perfect for me at LG. Not tried in budgi, but conditions are similar with floating weed a bit thicker in some places.


Yeah G, I should have written that I wanted to increase the surface area so that sailors with a generous amount of momentum muscle ( eg. me) could use it. Plus all the other sciencey reasons too of course

Tardy
4919 posts
29 Jul 2021 3:52PM
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looks fanging good ...its a break through ...

fangman
WA, 1238 posts
29 Jul 2021 7:26PM
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Tardy said..
looks fanging good ...its a break through ...


Haha - I would say the Titanic was a breakthrough on the drawing board too.
Thank you for the kind comment Tardy, but I have destroyed a lot of good fins thinking I was on to a good thing, so I will be disappointed if it's rubbish, but not sunk. I suspect that someone, probably in the eighties, has done this sort thing before and I just wasn't paying enough attention back then...

Tardy
4919 posts
31 Jul 2021 5:32PM
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ha ha ..its good someone is progressing with a shape ,for guys that sail in shallow areas ..well done ..
just a question ...with the sizes ..is there a area that comes with the fins ..as this matters also ..not that i know much about
your spunky fins ..and can you tell us more about the shape ..the change ..is it more for speed and DW speed ,as it seems more
swept back ..which i guess will be easier to push down wind ,and is the hollow to make them lighter or stronger ...sorry for the questions ..just interested ..



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"FangyFin 18 V2Speed - The Budgie special is off the drawing board!" started by fangman