Windsurf Canard fins

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.

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.

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.

Great Jim,
Looking forward to the next one.

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.

What an Ingenious and Creative windsurfing community we have

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

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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

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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:

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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 has some of those..

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.

Getting the Geek on there Jim, Nice work!

+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.