Author Topic: Vunderfoil  (Read 11200 times)

Admin

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Vunderfoil
« on: December 10, 2022, 09:50:08 AM »
Stoked on this.  I set this up in Fusion 360 so we are ready to iterate really easily.  It took awhile to get those .dat files from Airfoil tools to format, but I finally worked that out.  We can now import 100% design accurate sections into Fusion or Gravity Sketch with no tracing.  Now we are set up to dump any section straight into this file and it will copy out hands free to our four control loops.  We can basically hot swap sections.  The more you consider foils from a design perspective, the more you realize that the section is running the show. Changes now can happen really quickly.  This is a 400 mm symmetrical NACA 9 tail but within a few minutes it could be a 1300 cambered front wing with a different section, different outline, countours, washout, incidence,  you name it.  ...and my oven showed up yesterday :)
« Last Edit: December 10, 2022, 10:16:37 AM by Admin »

tarquin

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Re: Vunderfoil
« Reply #1 on: December 10, 2022, 10:27:19 AM »
This is just awesome. Well done.
 I know a big break for foiling was when they started designing specific foil shapes and not just using existing NACA or other shapes. I think with a pretty cheap CFD program you could really get to what you want to achieve quicker.
 As Pono said with your idea of attaching the mast to the front foil directly the fuse didn't need to be as strong. So if you had T shaped or elliptical fuse you wouldn't need a tail. Maybe a flexible fuse that gave you a little bit extra kick for pumping?  I think a CFD program would help with all of this.

Hdip

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Re: Vunderfoil
« Reply #2 on: December 10, 2022, 10:49:11 AM »
Where do I send my "sponsor me" video to?

PonoBill

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Re: Vunderfoil
« Reply #3 on: December 10, 2022, 11:30:46 AM »
This is just awesome. Well done.
 I know a big break for foiling was when they started designing specific foil shapes and not just using existing NACA or other shapes. I think with a pretty cheap CFD program you could really get to what you want to achieve quicker.
 As Pono said with your idea of attaching the mast to the front foil directly the fuse didn't need to be as strong. So if you had T shaped or elliptical fuse you wouldn't need a tail. Maybe a flexible fuse that gave you a little bit extra kick for pumping?  I think a CFD program would help with all of this.

That's a fascinating thought. Giampaolo has been experimenting with non-foiled (and really, non-winged) tails for some time. A t-shaped carbon fuselage could provide most or all the functions of a stabilizer with not a lot of drag. And it will be fairly easy to control how much, where, and in which directions each fuselage flexes

And Admin--shit, howdy! You're making it very hard to hang out in Maui dividing my time between wingfoiling, house maintenance, and stupid electronics projects. We'll be back in Mid-march so Diane can get a new knee (first of two). I don't usually get antsy to return to Hood River until air temp + river temp > 110, but this is just too cool.
« Last Edit: December 10, 2022, 11:40:12 AM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

tarquin

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Re: Vunderfoil
« Reply #4 on: December 10, 2022, 11:45:10 AM »
Very simple twist lock system of changing the fuse. You could have 3 or 4 in a backpack and change them in the water.

tarquin

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Re: Vunderfoil
« Reply #5 on: December 10, 2022, 11:50:48 AM »
Surely you can print a screw thread that stops in the same position.
 There are expensive fittings that exist in the sailing world. Maybe you could copy something like this.

tarquin

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Re: Vunderfoil
« Reply #6 on: December 10, 2022, 12:31:46 PM »
And then since you are 3D printing your own stuff have intake slots on the front of the main foil that sucks water in. A membrane or micro pump system that sucks water in and spits it out the back of of fuse like a jet ski. Magnetic impellers?
 If you are lucky you might create a super cavitating foil. That uses small amounts of electricity.

PonoBill

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Re: Vunderfoil
« Reply #7 on: December 10, 2022, 09:30:57 PM »
Admin, send me an STL file for that tail wing and I'll print a few up and try them. I have some carbon-reinforced polycarbonate kicking around--the good stuff, with fibers of CF instead of dust.
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

tarquin

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PonoBill

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Re: Vunderfoil
« Reply #9 on: December 10, 2022, 10:57:01 PM »
I doubt we'll really be using CFD tools unless someone offers something simple and relevant to foils. Fusion 360 has some CFD plugins, but they are general-purpose, more aimed at piping calculations and simulation I think. The Cadence software sounds like a LOT of work.

On an unrelated topic, I used to know some of the senior folks at Cadence, not that we'd get a discount or something. They'd probably charge me what Diane terms the Babcock Discount (retail plus ten percent), and they are probably retired by now anyway. When all the EDA companies were acquiring each other at a breathtaking pace we kept having our clients disappear into the maws of larger companies. Siemens was a client, and the internal rumor was that they were going to acquire Cadence. I was flying back from a meeting with Cadence when I learned Siemens had acquired Mentor Graphics. About a month later all our Seimens contacts disappeared when we were in the middle of a huge project with them. Poof, gone. It's hard to move a project along or get paid for all the work already done when the entire division disappears. I drove by the giant office building in Santa Clara a few weeks later and it was totally see-through, with not a single car in the huge parking lot. Dotcom collapse--weird times.

The Dark Aero videos do a great job of explaining aerodynamic concepts. There isn't a 100 percent transfer to hydrodynamics -- our medium (water) is incompressible for all practical purposes and about 1000 times more dense. But the fundamental components remain valid.

https://youtu.be/wRGuegKd5AQ
« Last Edit: December 10, 2022, 11:25:04 PM by PonoBill »
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

tarquin

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Re: Vunderfoil
« Reply #10 on: December 10, 2022, 10:59:16 PM »
You don't have to go this far. With a simple CFD program you could design 10 different fuses and test them in a morning. Get an idea of what shape and length works for what you want.

tarquin

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Re: Vunderfoil
« Reply #11 on: December 10, 2022, 11:03:53 PM »
Fundamentals are the same but huge gains got made when they stopped using aerofoils and designed hydrofoils.
 

tarquin

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Re: Vunderfoil
« Reply #12 on: December 10, 2022, 11:19:19 PM »
You can't make a wing 1000 times smaller and it will have the same characteristics in water as in air at the same speed.
 I would say Armstrong are using CFD with the connection to the Americas cup and Sail GP guys.
 Water temp, salinity density of water will all have an effect.
 Some guy might hate a foil and he is using it on a fresh water lake in Switzerland and another guy loves it that is using it in Australia in very salty water near the shore break with huge amounts of sand or sediment in the water. Same with damage to the leading edge. You are sand blasting it if you are foiling in water with sand or sediment in it.

Admin

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Re: Vunderfoil
« Reply #13 on: December 10, 2022, 11:26:40 PM »
This is just awesome. Well done.
 I know a big break for foiling was when they started designing specific foil shapes and not just using existing NACA or other shapes. I think with a pretty cheap CFD program you could really get to what you want to achieve quicker.
 As Pono said with your idea of attaching the mast to the front foil directly the fuse didn't need to be as strong. So if you had T shaped or elliptical fuse you wouldn't need a tail. Maybe a flexible fuse that gave you a little bit extra kick for pumping?  I think a CFD program would help with all of this.

Man, those are interesting ideas!  I love the idea of a CFD.  I know that autodesk (same parent as fusion 360 above) has one that integrates and it looks beyond cool.  I won't be able to resist that but, my brain is full right now.  :). I am laying in bed working out 3D hurdles and all the other related stuff.  I am pretty much the opposite of ADHD so too many directions is bad for Admin. On that note...

My immediate interest is working out the best system to quickly prototype, test, break, adjust, and iterate.  Enter the simple tail above.  That (or similar) is something I can print in 70 minutes and at 375 mm or so,  needs no glue, and I hope (with the right printer settings) only light prep before prepreg.  I believe we can get a super clean result from prepreg lamination directly onto the printed core.  The oven's controller has 3 sequenced heat/soak programs for each of their prepregs.  The range from a 14 hour 80 degree C max temp, to short 120 degree C option.  So, I am confident that we can bag and bake at full pressure without damaging our printed core (or mold if needed).  If we need to mold for certain parts, we can do that as well, but that is another thing to perfect. 

Gravity Sketch is amazing for rapid concept development.  Fusion 360 is incredibly complete but very stiff.  Every hardware catalog ever is available in Fusion, and it does projected parts, extrusion, etc with ease, so when it comes to various mounts and assembly stuff, that is pretty critical.  If you want 8  mm hardware from McMaster-Carr and corresponding coutersunk holes, you are going to work to get tat into GS but it is a few clicks in Fusion.

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Re: Vunderfoil
« Reply #14 on: December 10, 2022, 11:40:27 PM »
You can't make a wing 1000 times smaller and it will have the same characteristics in water as in air at the same speed.
 I would say Armstrong are using CFD with the connection to the Americas cup and Sail GP guys.
 Water temp, salinity density of water will all have an effect.
 Some guy might hate a foil and he is using it on a fresh water lake in Switzerland and another guy loves it that is using it in Australia in very salty water near the shore break with huge amounts of sand or sediment in the water. Same with damage to the leading edge. You are sand blasting it if you are foiling in water with sand or sediment in it.

Looking at the foil sections we are all using for our sports, they are all either from the existing databases or very close derivatives (intentionally or not).  That doesn't mean the configuration is the same (the same section can be used to make very different, purpose built wings), but I don't think you will find anything that strays far (if at all) from convention.

 


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