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.

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)

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.

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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.

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.

Good job Professor Flexafario. Methinks lots of potential prototypes to be made this winter.

Great Jim,
Looking forward to the next one.

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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

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.

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

What an Ingenious and Creative windsurfing community we have

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

I think these came after the canard fins by my memory, as fuzzy as it is

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.

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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

Gold Jerry, Gold.

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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:

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.

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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!!!!

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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

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YP1 said..
I think these came after the canard fins by my memory, as fuzzy as it is

I has some of those..

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

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.

Great stuff Jim!!! It's a real pleasure and honour to be a small part of this.

Getting the Geek on there Jim, Nice work!

Wow. Amazing work and video edit's of it.

+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.

Love your work Jim.