Windsurf Canard fins

2 years ago
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Flex2
Flex2
WA
373 posts
WA, 373 posts
20 Mar 2024 12:17pm
This could have been put on the Asymmetry thread or the Fangy Fin thread but thought I'd start another thread as interesting as topic on its own.

I was working on various flap mechanisms for a fin when Decrepit called me out of the blue and started talking about Canards and how, back in the old days he had made some and they increased the lift of a fin so dramatically he broke fins with them. Specifically he referred to free floating Canards, not fixed. I was intrigued so I started playing around with the concept.

Whilst it would have been easier to work on Canards for pointer style fins there aren't as many places to sail here with them so focused on using a standard Fangy Fin 22 as the base fin (since I can 3D print them cheaply). Instead of trying to make specific fins I made a board mod that allowed various Canard or camera modules to be inserted into the board.

Instead of waffling on, here is video on first experiments. Many mistakes and lessons learnt. Many thanks to Elmo for the donor board and Decrepit for inspiration and advice and help with board mods.

Flex2
Flex2
WA
373 posts
WA, 373 posts
20 Mar 2024 1:02pm
Mainly posting this for Boardsurfr. Just tried the new GPSSpeedreader awesome new polar plots and they confirm the canard fin (foresail version) improved upwind performance reasonably on light wind day (VMG and heading). (Note not a large data set so don't take it as gospel)





Paducah
Paducah
2849 posts
2849 posts
20 Mar 2024 1:05pm
I hope this isn't too far off topic but I noticed the VGs at 0:33 in the video. I wanted to experiment with them to smooth the flow over a carry handle on the bottom of a board. Are they discussed elsewhere already? If not, I'll start a separate thread.

Back to the main topic, absolutely fascinating what you all are doing. It's a pleasure to watch the experiments and lessons learned.
BSN101
BSN101
WA
2391 posts
WA, 2391 posts
20 Mar 2024 2:06pm
Flex2 said..
This could have been put on the Asymmetry thread or the Fangy Fin thread but thought I'd start another thread as interesting as topic on its own.

I was working on various flap mechanisms for a fin when Decrepit called me out of the blue and started talking about Canards and how, back in the old days he had made some and they increased the lift of a fin so dramatically he broke fins with them. Specifically he referred to free floating Canards, not fixed. I was intrigued so I started playing around with the concept.

Whilst it would have been easier to work on Canards for pointer style fins there aren't as many places to sail here with them so focused on using a standard Fangy Fin 22 as the base fin (since I can 3D print them cheaply). Instead of trying to make specific fins I made a board mod that allowed various Canard or camera modules to be inserted into the board.

Instead of waffling on, here is video on first experiments. Many mistakes and lessons learnt. Many thanks to Elmo for the donor board and Decrepit for inspiration and advice and help with board mods.



Can you just trim the front off the green canard which effectively moves the pivot point forward.
Flex2
Flex2
WA
373 posts
WA, 373 posts
20 Mar 2024 3:33pm
Yes I could just trim the front BSN101, but doing so will expose all the hollow infill in the 3d print (it's not solid) plus lose the airfoil shape so will be a dogs breakfast. Need to maintain the 55 deg slope to stop weed which means need to also trim the metal boat rudder plus make a new weed plough. Much easier to just print again as only a few cents. I also managed to bust this particular rudder trying to remove the print from rudder (siliconed on) so have to redo the whole thing anyway. Luckily I scored 3 of them for $1.
fangman
fangman
WA
1906 posts
WA, 1906 posts
20 Mar 2024 5:06pm
Good job Professor Flexafario. Methinks lots of potential prototypes to be made this winter.
decrepit
decrepit
WA
12887 posts
WA, 12887 posts
20 Mar 2024 5:10pm
Great Jim,
Looking forward to the next one.
BSN101
BSN101
WA
2391 posts
WA, 2391 posts
20 Mar 2024 5:36pm
Flex2 said..
Yes I could just trim the front BSN101, but doing so will expose all the hollow infill in the 3d print (it's not solid) plus lose the airfoil shape so will be a dogs breakfast. Need to maintain the 55 deg slope to stop weed which means need to also trim the metal boat rudder plus make a new weed plough. Much easier to just print again as only a few cents. I also managed to bust this particular rudder trying to remove the print from rudder (siliconed on) so have to redo the whole thing anyway. Luckily I scored 3 of them for $1.


Weight the tail to shift CE? I didn't realise that it was
also to shed weed, nor the build. Just thunking when I saw the shape.
Great inspirational work as usual Flex, keep at it, Dave (thumbs up)x2
boardsurfr
boardsurfr
WA
2463 posts
WA, 2463 posts
20 Mar 2024 11:10pm
Amazing what you get when you put together a former dentist, an engineer with all the good toys and plenty of time, and a decrepit guy with decades of experience ! I'd love to see some CFD simulation videos that show why/how Canards work, or hear some theories. Deflecting air bubbles from reaching the front of the fin comes to my mind, but not sure if that makes any sense.
decrepit
decrepit
WA
12887 posts
WA, 12887 posts
21 Mar 2024 8:04am
Peter, my understanding is that it increases the flow across the leeward side of main foil. Intensifying the low pressure and increasing lift. reducing angle of attack, and tendency to stall and vetilate
hardie
hardie
WA
4133 posts
WA, 4133 posts
21 Mar 2024 8:48am
What an Ingenious and Creative windsurfing community we have
MrFussy
MrFussy
WA
16 posts
WA, 16 posts
21 Mar 2024 11:52am
Bloody good work gang, so good to see this kind of testing being done. Theory's are all well and good but testing is where it's at.I like the sail type canard, I think the slot is better between it and the fin and would most likely be the one that would mostly hack the pace under load in the end (in engineering terms anyway). Think you will get the most benefit from the canards under load getting back upwind, keep up the good work.
Nice video too
YP1
YP1
SA
136 posts
YP1 YP1
SA, 136 posts
21 Mar 2024 7:10pm
I think these came after the canard fins by my memory, as fuzzy as it is



ned321
ned321
99 posts
99 posts
22 Mar 2024 2:49pm
A bit off-topic, but the topic title had me chuckling.

There are a number of examples of car model names, that caused those models to fail miserably.
Two famous examples:
1. Chevrolet Nova. In spanish, "no va" means "does not run".
2. Fiat Croma. In the NL and surroundings, Croma was the most used brand of baking butter.

Canard, in french, has 2 meanings:
1. Duck.
2. News item with lots of attention, which later was found to be fake.
Flex2
Flex2
WA
373 posts
WA, 373 posts
22 Mar 2024 6:20pm
ned321 said..
A bit off-topic, but the topic title had me chuckling.

There are a number of examples of car model names, that caused those models to fail miserably.
Two famous examples:
1. Chevrolet Nova. In spanish, "no va" means "does not run".
2. Fiat Croma. In the NL and surroundings, Croma was the most used brand of baking butter.

Canard, in french, has 2 meanings:
1. Duck.
2. News item with lots of attention, which later was found to be fake.




Well, learnt something there. Didn't know that. This will probably will stuff this thread by replying but you can add the Audi E-Tron to your list of car names. Surely Audi (being European) knows what it means in French..but obviously not..they now have all their 9 EV offerings branded as E-Tron. Surely they can't all be "Turds"??

To be fair etron = turd but for English speakers etron=etron

Edit:- Seems Seabreeze can't do the e with the thingo's above them and the French have 5 different ways of writing e. thus the attached pic. from google translate

fangman
fangman
WA
1906 posts
WA, 1906 posts
23 Mar 2024 8:38am
Gold Jerry, Gold.
sailquik
sailquik
VIC
6173 posts
VIC, 6173 posts
24 Mar 2024 2:11pm
boardsurfr said..
Amazing what you get when you put together a former dentist, an engineer with all the good toys and plenty of time, and a decrepit guy with decades of experience ! I'd love to see some CFD simulation videos that show why/how Canards work, or hear some theories. Deflecting air bubbles from reaching the front of the fin comes to my mind, but not sure if that makes any sense.



Perhaps looking at the way foresails work on Yachts has relevance?

However it works, I can confirm though many miles over many years that 'canard' fins dramatically reduce, even eliminate spin out.

The probable downside may be more drag, but I remember an incident many, many years ago when Amac came to Sandy Point to do some sail testing with some of his Prototype Wild Winds sails with me. We had near identical boards but all I had with me that day was a 'slot' fin, compared with his flash 'pointer' fin.

He said that just won't do as that fin will be sooooo much slower. I said let's just try it and see.

After many side by side runs swapping boards and sails, it became so apparent that the difference was almost undetectable that he finally conceded it was comparable in speed, and spent some time studying that 'slot. fin. To this day I have no idea why that fin worked so well.

Here it is, in obviously very poor condition now, oh, about 35 years later:




I know I had some canard, or 'Fore Fins' somewhere, but had a search and have not yet found them.

This is from an old Tyronsea Brochure:


diamondjim
diamondjim
WA
3 posts
WA, 3 posts
25 Mar 2024 11:14am
Given there have been a couple of photos of slot fins on this topic, I thought you might like to see one I fitted just as I was moving away from windsurfing (distracted by birds and booze), and so it's essentially new. This was fitted to my 1982 Bombora Proto, and I installed it about 1985. The small fin in front is to lock it in place, but I'm not sure if it was supposed to act as some form of fixed canard.





peterowensbabs
peterowensbabs
NSW
499 posts
NSW, 499 posts
1 Apr 2024 5:40pm
Flex2 said..

ned321 said..
A bit off-topic, but the topic title had me chuckling.

There are a number of examples of car model names, that caused those models to fail miserably.
Two famous examples:
1. Chevrolet Nova. In spanish, "no va" means "does not run".
2. Fiat Croma. In the NL and surroundings, Croma was the most used brand of baking butter.

Canard, in french, has 2 meanings:
1. Duck.
2. News item with lots of attention, which later was found to be fake.





Well, learnt something there. Didn't know that. This will probably will stuff this thread by replying but you can add the Audi E-Tron to your list of car names. Surely Audi (being European) knows what it means in French..but obviously not..they now have all their 9 EV offerings branded as E-Tron. Surely they can't all be "Turds"??

To be fair etron = turd but for English speakers etron=etron

Edit:- Seems Seabreeze can't do the e with the thingo's above them and the French have 5 different ways of writing e. thus the attached pic. from google translate


Try Pajero in Spanish!!!!
tony d ford
tony d ford
VIC
12 posts
VIC, 12 posts
2 Apr 2024 2:54pm
YP1 said..
I think these came after the canard fins by my memory, as fuzzy as it is




I had one of those too, and I even re-jigged old plastic fins to trial the little lock it in canard as per elsewhere here before trying it on the better fins back in 80s'90's. fun times
sboardcrazy
sboardcrazy
NSW
8354 posts
NSW, 8354 posts
3 Apr 2024 2:11pm
YP1 said..
I think these came after the canard fins by my memory, as fuzzy as it is




I has some of those..
ausbinny
ausbinny
203 posts
203 posts
10 Apr 2024 9:21am
Anyone have a go of a split fin? was my favorite on my Hookipa (although it wasn't a "wave" fin) it was fast (for the time) and basically impossible to spin out

It was basically a carnard that almost matched the main fin in height with a main fin that was also very high aspect
Flex2
Flex2
WA
373 posts
WA, 373 posts
9 May 2024 8:51pm
Finally got some wind after 5 weeks to try V2 versions of the rotating Canards plus some other wacky ideas. The test window of wind was only about 2hrs so is all a bit rushed but end result was I am convinced any form of canard (fixed, rotating or foresail) improves fin performance significantly.

Judge for yourself in video below. Its long and nerdy so only watch if you have a nice cup of tea/wine handy.

Thanks in advance to Fangman, Elmo, Decrepit and Boardsurfr who in one way or another have contributed to this concept.

decrepit
decrepit
WA
12887 posts
WA, 12887 posts
9 May 2024 9:33pm
Great stuff Jim!!! It's a real pleasure and honour to be a small part of this.
elmo
elmo
WA
8896 posts
WA, 8896 posts
10 May 2024 6:01am
Getting the Geek on there Jim, Nice work!
MobZ
MobZ
NSW
536 posts
NSW, 536 posts
10 May 2024 11:35pm
Wow. Amazing work and video edit's of it.
fangman
fangman
WA
1906 posts
WA, 1906 posts
11 May 2024 11:20am
+1 on what they^ said Prof Flexafario. Sending you some interesting research from Prof Traub. (the fella that did all the research on the annular wing) It's all low Re stuff but well worth a read.
sailquik
sailquik
VIC
6173 posts
VIC, 6173 posts
11 May 2024 10:38pm
Love your work Jim.
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