Standup Zone Forum

General => The Shape Shack => Topic started by: Admin on December 10, 2022, 09:50:08 AM

Title: Vunderfoil
Post by: Admin 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 :). 
Title: Re: Vunderfoil
Post by: tarquin 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.
Title: Re: Vunderfoil
Post by: Hdip on December 10, 2022, 10:49:11 AM
Where do I send my "sponsor me" video to?
Title: Re: Vunderfoil
Post by: PonoBill 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.
Title: Re: Vunderfoil
Post by: tarquin 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.
Title: Re: Vunderfoil
Post by: tarquin 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.
Title: Re: Vunderfoil
Post by: tarquin 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.
Title: Re: Vunderfoil
Post by: PonoBill 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.
Title: Re: Vunderfoil
Post by: tarquin on December 10, 2022, 10:43:33 PM
https://www.numeca.com/vplp-design-revolutionizing-hydrofoil-design-with-advanced-cfd-simulation-technology
Title: Re: Vunderfoil
Post by: PonoBill 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
Title: Re: Vunderfoil
Post by: tarquin 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.
Title: Re: Vunderfoil
Post by: tarquin 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.
 
Title: Re: Vunderfoil
Post by: tarquin 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.
Title: Re: Vunderfoil
Post by: Admin 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.
Title: Re: Vunderfoil
Post by: Admin 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.
Title: Re: Vunderfoil
Post by: PonoBill on December 10, 2022, 11:48:20 PM
Yeah, the biggest problem with Fusion 3D is that it's parametric to the core. It feels kind of free form when you are extruding rectangles into boxes, but to be adept at it you need to learn it from the parametric side before you start pulling and pushing stuff.

Tarquin, I understand what you're saying about sediment and salt density variations--if only because I converted my bead blaster into a vapor blaster. Add water to the bead blasting process and it's a whole different thing.

I am about as far away from Admin on the neurological fuckup spectrum as is feasible. Completely unmanaged ADHD. I'll probably have to pop some Concerta so we can work together. I have some left over from when I worked for a living. I wonder what the expiration date is on that stuff.

I am sure we can laminate over 3D-printed parts. I'm printing some polycarbonate parts right now with enough infill that they could be bagged pretty hard. The temperature is a concern as well, but if the ramp is right the CF would be set before the core gets wonky. Polycarbonate melts at about 180C but loses strength before that temp. I'll have to do some research to see what the curve looks like. The easy composite guy didn't have any problem with the huge mold he made, and as I recall that was PET, which is generally weaker and lower temp.
Title: Re: Vunderfoil
Post by: PonoBill on December 10, 2022, 11:58:18 PM
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.

I think there's room for improvement in foil performance without getting too exotic. Most of the main wings I've looked at use washout to control how the foil stalls. You can get a similar result (stall at the root before the tips) by varying the foil cross-section from root to tip. And you can reduce both parasitic and lift-related drag at the wingtips--washout is draggy. The Dark Aero video I linked above talks about that approach briefly. They transition from a conventional asymmetric foil to a more symmetric cross-section at the wingtips. Something more to try. 
Title: Re: Vunderfoil
Post by: PonoBill on December 11, 2022, 12:09:56 AM
Using my printer to make parts for my printer. It feels quite recursive until you notice the aluminum tape holding the fan in place. I think of this as my "old" printer though it's only a year old. If I printed this on the Bambu printer with the same material you would barely see the layer lines.
Title: Re: Vunderfoil
Post by: Admin on December 11, 2022, 12:11:35 AM
Yeah, the biggest problem with Fusion 3D is that it's parametric to the core. It feels kind of free form when you are extruding rectangles into boxes, but to be adept at it you need to learn it from the parametric side before you start pulling and pushing stuff.

Tarquin, I understand what you're saying about sediment and salt density variations--if only because I converted my bead blaster into a vapor blaster. Add water to the bead blasting process and it's a whole different thing.

I am about as far away from Admin on the neurological fuckup spectrum as is feasible. Completely unmanaged ADHD. I'll probably have to pop some Concerta so we can work together. I have some left over from when I worked for a living. I wonder what the expiration date is on that stuff.

I am sure we can laminate over 3D-printed parts. I'm printing some polycarbonate parts right now with enough infill that they could be bagged pretty hard. The temperature is a concern as well, but if the ramp is right the CF would be set before the core gets wonky. Polycarbonate melts at about 180C but loses strength before that temp. I'll have to do some research to see what the curve looks like. The easy composite guy didn't have any problem with the huge mold he made, and as I recall that was PET, which is generally weaker and lower temp.

With Fusion, everything is easy, until you realize that the easy way distorts your section loops and you are left with pretty garbage.  That is why all of the foil instructional vids are using straight, non curved wings or wings of fused straight segments.  To get it right you need to be very careful with setup and order.  You need to get the planes done first and everything constrained before you begin. or the loft tools will throw errors.  These tools are very specific about the rails and guides that they will allow and we need all profiles and all guides to engage.  It took me 72 hours to get it, but we now have full control over leading and trailing edge independently, with infinite stage root to tip contouring and rotational control all while maintaining a perfect source .dat profile everywhere.  I am pretty stoked about that :)
Title: Re: Vunderfoil
Post by: tarquin on December 11, 2022, 12:16:37 AM
I have no idea either. I just know at some point you should have designed a hydro foil and not down sized an aeroplane wing.
 Good luck and remember. You didn't make a mistake you learnt something. It's only a mistake if you stop trying and didn't learn something from it.
Title: Re: Vunderfoil
Post by: Admin on December 11, 2022, 06:18:15 AM
I agree that we don't want to be using airplane wings or downsized airplane wings and I would not have interest in doing that.  This one (maybe upsized to a front wing?) is based on a lightly cambered section, its thickness is at 10.25%.  This section is a morph between two sections, one of which is common in current watersport foils (reverse engineering makes that clear).  Essentially if you put a foil on one end and a banana on the other, in the middle, software will produce a foilnana.  You won't want to ride it or eat it, but...

Title: Re: Vunderfoil
Post by: PonoBill on December 11, 2022, 08:33:12 AM
I have sporadic experience with Fusion 3D (hmmm, that's more or less true with everything I do). I have to go back to basics every time I restart using it seriously. I've never done anything complex with it though I've been dinking around with it for years. But it (or some competitor) is a core requirement for doing anything useful with a 3D printer or laser cutter, and I do enough of that to maintain some level of attention.

You are absolutely right about things falling to shit if you don't get the 2d plane right. The most frustrating moments are when you turn something into 3D and it won't move, copy, rotate, or otherwise do 3d shit. It's ALWAYS because the constraints are wrong. I think you're a long way past my high water mark. So I've got a goal. Goals are good.
Title: Re: Vunderfoil
Post by: finbox on December 11, 2022, 09:17:07 AM
Hi,
Have you been able to run a Computational Fluid Dynamics (CFD) program with the proposed foil shape? If you can compare it to a know front foil - this could help validate you design prior to making it real.
Title: Re: Vunderfoil
Post by: PonoBill on December 11, 2022, 10:19:34 AM
From my lightweight research it looks like we should be fine using polycarbonate for prepreg laminating. It maintains toughness up to 140C, which is surprising since it starts to melt at 155C. I suspect, but haven't been able to verify, that once it's been melted and formed the melting temperature might be higher. I generally print it at 260 to 280C with the bed heated to 90C--the Bambu labs printer can do that handily since the print head is all metal. I'm not sure why they do this, but the printer nozzles for the Bambu printer are not replaceable--you need to replace the entire head, transferring only the heating element and thermistor. It's probably a more accurate head than a screw-in nozzle would permit. The heads are relatively cheap ($15) and are available in a variety of nozzle sizes and materials. I bought one of each size and material (brass, hardened steel, etc.). Now that I'm screwing around with my Prusa printer again I've got to say, I love that Bambu Labs printer. It prints ABS like it's PLA. and PLA parts come out looking like they were injection molded. Printing ABS on the Prusa is nearly pointless except for very small parts. I use a filament dryer for everything and the ABS still pops and warps like wet filament.
Title: Re: Vunderfoil
Post by: surfcowboy on December 11, 2022, 01:34:06 PM
Admin, this is inspiring.

I'm working out a printer now myself. Let me know if you guys want me to take a bullet wet laminating one of these when you get some protos cooked up.
Title: Re: Vunderfoil
Post by: PonoBill on December 11, 2022, 02:21:03 PM
Cowboy, I don't know your application, but take a look at the Bambu Labs X-1 Carbon printer. You'll have to wait a while for it, but they're saying end of December now. That might slip. I got mine about a month before I left for Maui and I was blown away. So much so that I thought about shipping it here, but decided to ship my Prusa instead. If only because the Prusa can be disassembled into a small-ish box and the Bambu can't.

I've got a lot of printers, if I include ones I haven't used in a while it's probably eight or nine. I use mine a lot to make custom parts, replacement parts, molds, prototypes, etc. a lot of the stuff I used to make out of metal with milling, welding, sheet forming, riveting, etc. I now just print. There seem to be two kinds of people who buy 3D printers. Those that like the tech and print tchotchkes, and people who make parts. Well, there's a third kind too--those who get one, don't really have a use for it, and give it to me. Two of my printers came from them.

I would normally say if you need a build area bigger than 230x230x230mm then you need a different printer, but the slicer for the Bambu Labs handles splitting big stuff into chunks for assembly with startling ease and accuracy. Take a look here. some of the more critical comments were handled in subsequent software updates (which are frequent and painless).
https://forum.3dprintbeginner.com/t/bambu-lab-x1-carbon/479/26
Title: Re: Vunderfoil
Post by: jondrums on December 11, 2022, 06:33:57 PM
The foil sections used on wings and tails these days are MOST CERTAINLY NOT standard NACA sections.  Not even close.  I extracted sections from several different wings I have owned and I know this for a fact.

The CFD program to use is XFOIL.  This is a really simple 2D CFD for foil sections.  You can get lift and drag vs. angle of attack for various reynolds numbers (speeds).  It takes a bit of skill to understand how to read these outputs, but put in some time reading up on it and you can figure it out.  There are a number of third party softwares available that use the open source XFOIL core and put a GUI on top.

But before you do this, consider just taking a moment to extract the foil section from a foil you really like and copying that - this picture should show you how to do it:
(https://i.imgur.com/G6tNPd3.jpeg)
Title: Re: Vunderfoil
Post by: Admin on December 11, 2022, 11:13:41 PM
The foil sections used on wings and tails these days are MOST CERTAINLY NOT standard NACA sections.  Not even close.  I extracted sections from several different wings I have owned and I know this for a fact.

The CFD program to use is XFOIL.  This is a really simple 2D CFD for foil sections.  You can get lift and drag vs. angle of attack for various reynolds numbers (speeds).  It takes a bit of skill to understand how to read these outputs, but put in some time reading up on it and you can figure it out.  There are a number of third party softwares available that use the open source XFOIL core and put a GUI on top.

But before you do this, consider just taking a moment to extract the foil section from a foil you really like and copying that - this picture should show you how to do it:

The Xfoil data already is given for the thousands of sections that are present at the online databases.  My comment was that what is being used by foil makers is already there, whether intentional or not, and that you can confirm this for yourself by reverse engineering (as in your image).  Once you have your section dimensions you can search the databases by these dimensions and the sites will produce all foils of these dimensions. Scan through those and you will find your section.  You can then download and overlay your measured section in software.  That is really interesting to see where else these foil sections are in use.

http://airfoiltools.com/search/airfoils
https://m-selig.ae.illinois.edu/ads/coord_database.html

The provided info, in combination with knowing what is already in use for our sports, is super helpful in selecting a start point section for home builder designs such as ours. 

That is primarily for sections though and some provided testing for straight wings produced form these sections.    Tarquin and finbox (thanks for the push guys!) are suggesting running analysis based on our produced wing export files and I want to do that.  If you guys know of something accessible please let me know. This will be most valuable when we can export a finished system (both wings, fuse, mast, hardware) and test as a whole but the individual components will be interesting as well. 
Title: Re: Vunderfoil
Post by: Admin on December 12, 2022, 12:15:39 AM
Where do I send my "sponsor me" video to?

We will build some pass-around wings for sure.  Once we get some rolling and have some designs with merit, consider yourself signed up.
Title: Re: Vunderfoil
Post by: PonoBill on December 12, 2022, 08:35:40 AM
I think current foil manufacturers are missing an obvious bet. They sponsor kids with supernatural talents to showcase their expensive gear, that no kid could possibly buy without willing investment from Dad and/or Mom. The target audience is geezers and sub-geezers, and the marketing message should be simple: "Our wings are so great that even Bill can do this". Cut to a video clip of me wobbling through a jibe, blowing a tack, and straining to get to my feet during a knee start. Marketing magic. You're welcome.

Then again I'm not sure of Admin's ambitions but the thought of doing this commercially makes me gag. It will be great fun, and perhaps it can stave off the inevitable decline of my cognitive ability. Wait, what was I writing about??
Title: Re: Vunderfoil
Post by: Admin on December 12, 2022, 10:13:31 AM
I think current foil manufacturers are missing an obvious bet. They sponsor kids with supernatural talents to showcase their expensive gear, that no kid could possibly buy without willing investment from Dad and/or Mom. The target audience is geezers and sub-geezers, and the marketing message should be simple: "Our wings are so great that even Bill can do this". Cut to a video clip of me wobbling through a jibe, blowing a tack, and straining to get to my feet during a knee start. Marketing magic. You're welcome.

Then again I'm not sure of Admin's ambitions but the thought of doing this commercially makes me gag. It will be great fun, and perhaps it can stave off the inevitable decline of my cognitive ability. Wait, what was I writing about??

My interest in foil gear is entertainment, edification and personal enlightenment.  This is a pleasure ride.
Title: Re: Vunderfoil
Post by: PonoBill on December 12, 2022, 10:17:15 AM
The CFD program to use is XFOIL.  This is a really simple 2D CFD for foil sections.  You can get lift and drag vs. angle of attack for various reynolds numbers (speeds). 

That sounds kind of promising, it would be nice to not just try stuff blindly. I've never completely understood Reynolds Number, but I don't generally equate it to speed but rather inertia--which of course includes velocity as a factor--and viscosity of the working fluid. Given the much higher mass and viscosity of water vs. air I wonder if CFD intended for airfoils is relevant to hydrofoils.
Title: Re: Vunderfoil
Post by: PonoBill on December 12, 2022, 10:20:16 AM
My interest in foil gear is entertainment, edification and personal enlightenment.  This is a pleasure ride.

I assumed so, but good to know we are in complete alignment. You know very well I'm allergic to the actual responsibility involved in real business.
Title: Re: Vunderfoil
Post by: jondrums on December 12, 2022, 10:23:42 AM
My comment was that what is being used by foil makers is already there, whether intentional or not, and that you can confirm this for yourself by reverse engineering (as in your image). 

What I am saying is that no, they are in fact NOT in those databases.  I already confirmed that.  Subtle differences in shape do make quite a difference
Title: Re: Vunderfoil
Post by: jondrums on December 12, 2022, 10:30:37 AM
I've never completely understood Reynolds Number, but I don't generally equate it to speed but rather inertia--which of course includes velocity as a factor--and viscosity of the working fluid. Given the much higher mass and viscosity of water vs. air I wonder if CFD intended for airfoils is relevant to hydrofoils.

You are right about the Reynolds number including viscosity of the fluid, and it also includes the approximate scale of the bodies under study.  But after that, higher speed -> higher reynolds number. 

For water, use a Reynolds number of about 0.8x10^6 for 15 mph and go up and down linearly from there.

And yes, XFOIL works quite well for both air and water - that's exactly what the reynolds number is there to compensate for.
Title: Re: Vunderfoil
Post by: tarquin on December 12, 2022, 10:30:50 AM
You need to use a program for hydrofoils.
 I have been lucky enough to meet people that have been involved in some pretty high end foiling sailing. They said the major break through was designing hydrofoils not just using existing NACA shapes.
 What you see doing is awesome and I love it. It will work and you will make some great stuff. But if you want to give it that little bit extra some proper CFD will make a big difference.
 It would be interesting to know if the Armstrong foils are different to other foils.
 
 
Title: Re: Vunderfoil
Post by: Hdip on December 12, 2022, 10:41:22 AM
I think current foil manufacturers are missing an obvious bet. They sponsor kids with supernatural talents to showcase their expensive gear, that no kid could possibly buy without willing investment from Dad and/or Mom. The target audience is geezers and sub-geezers, and the marketing message should be simple: "Our wings are so great that even Bill can do this". Cut to a video clip of me wobbling through a jibe, blowing a tack, and straining to get to my feet during a knee start. Marketing magic. You're welcome.

Isn't this what AXIS is all about already? Stiffest mast! The "standard" fuses with the mast position in a dumbed down position. Massive wings larger than almost any other manufacturer.
Title: Re: Vunderfoil
Post by: Admin on December 12, 2022, 11:07:34 AM
You need to use a program for hydrofoils.
 I have been lucky enough to meet people that have been involved in some pretty high end foiling sailing. They said the major break through was designing hydrofoils not just using existing NACA shapes.
 What you see doing is awesome and I love it. It will work and you will make some great stuff. But if you want to give it that little bit extra some proper CFD will make a big difference.
 It would be interesting to know if the Armstrong foils are different to other foils.

I am very interested in that.  I will do more digging when we get closer to complete.  If anyone knows of an option offhand that accepts common export file types, I would love to know.  My gut is that we stand to gain a lot more efficiency and usability from the non section related adjustments than from any potential improvements to sections, but of course that is all hot air at this point.  There is some funny stuff looking back at this vid.  https://youtu.be/wvy2OzfH4N4?t=1143
Title: Re: Vunderfoil
Post by: Hdip on December 12, 2022, 11:20:49 AM
These guys do a lot of computer analysis. Might be able to get some tips from them. This is the only thing I could find of it with an easy search. The designer has posted on other forums talking about it though.

https://www.indefoil.com/foildesign/mast-thickness-drag
Title: Re: Vunderfoil
Post by: PonoBill on December 12, 2022, 11:41:50 AM
The Armstrong video is pretty cool. I like their stuff. the only reason I went for axis initially was the connection of the fuselage to the wing--I knew I could reproduce that connection in wings with my primitive capabilities.

Every youtube video I look at these days offers me all kinds of Autism information in the sidebar videos. Somebody has been ratting on me.
Title: Re: Vunderfoil
Post by: Califoilia on December 12, 2022, 12:18:47 PM
I think current foil manufacturers are missing an obvious bet. They sponsor kids with supernatural talents to showcase their expensive gear, that no kid could possibly buy without willing investment from Dad and/or Mom. The target audience is geezers and sub-geezers, and the marketing message should be simple: "Our wings are so great that even Bill Califoilia can do this". Cut to a video clip of me him wobbling through a jibe, blowing a tack, and straining to get to my his feet during a knee start. Marketing magic. You're welcome.
Fixed it for you, because I know of one company that has done that for a couple years now...and that same "geezer foiler" has demos on the beach for folks to "try before they buy". :-X ;D
Title: Re: Vunderfoil
Post by: Admin on December 12, 2022, 11:37:16 PM
These guys do a lot of computer analysis. Might be able to get some tips from them. This is the only thing I could find of it with an easy search. The designer has posted on other forums talking about it though.

https://www.indefoil.com/foildesign/mast-thickness-drag

One interesting thing that I have found is how many sections are in use on a foil kit.  We tend to think wings and mast, but foil sections or partial foil sections are also being used for pedestals, bulbs and connections.  In the link he is not only testing mast width, but also a completely different section.  Not a criticism, just a note of interest, because there is no perfect way to test there.  This is actually very easy to do by mistake in software and great care needs to be taken to maintain your section (at least to remain intentional).  He is testing two NACA sections, not that they would use those :)
Title: Re: Vunderfoil
Post by: Admin on December 12, 2022, 11:49:24 PM
As mentioned in the OP we can now hot swap sections (downloads, scans, tweens, morphs, banana) and export to all common file types, so if we have software we can simulate.  I put in a ticket with Autodesk regarding their CFD.  It appears to be windows only??  but I still have a windows machine here if needed:).  Fusion has built in simulation features which are excellent but not applicable for wind or fluid.  I found a Fusion app store extension but it is goofy.  Fusion has a simulation extension https://www.autodesk.com/products/fusion-360/simulation-extension?term=1-YEAR&tab=subscription , which I now want for other uses but it doesn't do wind or fluid AFAICT.  I see them moving towards a unified cloud based platform for everything (which is what Fusion 360 is becoming) so hopefully the CFD will become tightly integrated soon.  I know that I would spring for the simulation extension pack if this were there.  Here is there CFD.  It looks extremely fiddly, even by Autodesk standards and I think it would be a great job for Bill.  Hah!

https://www.youtube.com/watch?v=nS9SfKLdkw4
Title: Re: Vunderfoil
Post by: Admin on December 13, 2022, 12:49:09 AM
Oooh, my printer and a buttload of CF filament (PA-CF and PC-CF) plus goodies shipped today.  Should be ready to rumble soon...
Title: Re: Vunderfoil
Post by: PonoBill on December 13, 2022, 10:58:38 AM
Here is their CFD.  It looks extremely fiddly, even by Autodesk standards and I think it would be a great job for Bill.  Hah!

Yikes, that looks like at least a three Concertatm job.
Title: Re: Vunderfoil
Post by: burchas on December 13, 2022, 01:45:46 PM
As mentioned in the OP we can now hot swap sections (downloads, scans, tweens, morphs, banana) and export to all common file types, so if we have software we can simulate.  I put in a ticket with Autodesk regarding their CFD.  It appears to be windows only??  but I still have a windows machine here if needed:).  Fusion has built in simulation features which are excellent but not applicable for wind or fluid.  I found a Fusion app store extension but it is goofy.  Fusion has a simulation extension https://www.autodesk.com/products/fusion-360/simulation-extension?term=1-YEAR&tab=subscription , which I now want for other uses but it doesn't do wind or fluid AFAICT.  I see them moving towards a unified cloud based platform for everything (which is what Fusion 360 is becoming) so hopefully the CFD will become tightly integrated soon.  I know that I would spring for the simulation extension pack if this were there.  Here is there CFD.  It looks extremely fiddly, even by Autodesk standards and I think it would be a great job for Bill.  Hah!

https://www.youtube.com/watch?v=nS9SfKLdkw4

Admin, how did you go about choosing Fusion-360 as your tool for this endeavor?
Reading through your challenges it sounds like Rhino3D offer a path with less resistance:

- Widely used in the Marine world (including America’s Cup)
- Good community support on that segment
- Mac compatible
- Nemo plugin for everything marine design including Hydrofoils
- A selection of CFD plugins
- Pay to own license rather then a blood sucking subscription model

Hope that helps :)
Title: Re: Vunderfoil
Post by: jondrums on December 13, 2022, 06:12:51 PM
These guys do a lot of computer analysis. Might be able to get some tips from them. This is the only thing I could find of it with an easy search. The designer has posted on other forums talking about it though.

https://www.indefoil.com/foildesign/mast-thickness-drag

I happen to know for a fact that the fellow designing INDE foils is using XFLR5 (http://"https://engineering.purdue.edu/~aerodyn/AAE333/FALL10/HOMEWORKS/HW13/XFLR5_v6.01_Beta_Win32%282%29/Release/Guidelines.pdf"), which is a front end for XFOIL CFD codebase to analyze not just the foil section but the entire mast, fuse, wing and tail
Title: Re: Vunderfoil
Post by: Admin on December 13, 2022, 11:17:07 PM
These guys do a lot of computer analysis. Might be able to get some tips from them. This is the only thing I could find of it with an easy search. The designer has posted on other forums talking about it though.

https://www.indefoil.com/foildesign/mast-thickness-drag

I happen to know for a fact that the fellow designing INDE foils is using XFLR5 (http://"https://engineering.purdue.edu/~aerodyn/AAE333/FALL10/HOMEWORKS/HW13/XFLR5_v6.01_Beta_Win32%282%29/Release/Guidelines.pdf"), which is a front end for XFOIL CFD codebase to analyze not just the foil section but the entire mast, fuse, wing and tail

Thanks Jon, I really appreciate the suggestion.  This will be fun to use.  I did some searching and it appears (where full wings are involved) that XFLR5 acts as the wing creation tool.  It looks like it is primarily allows for basic extruded or surfaced sections or joined sections created this way at angles.  We already have data for thousands of existing sections and for straight extrusions of those sections.  That is where our section choice is currently beginning (along with what is already known to be in use).  I am not finding any example of flowing curve structures like we use for our foiling sports or any way to create that in this software.  I am also not finding any way to import our outside created structure (or grouped structures, which is really where we need to be).  Maybe that functionality exists but Google and the support docs are not readily clear on that.

Wings with our flowing 3D curves are actually very challenging to create and control in software while maintaining section integrity.  You have to use a different tool path (other than simple extrusion or surfacing).  What he  does in this video (essentially import two dat section files and then straight surface them) can't be used to create our wings.  Neither can the next two easiest tool paths in outside CAD software.   He is using one section for the wingtips and another for the root so he essentially has infinitesimal sections in between.  I wonder what Inde is using this for.

https://www.youtube.com/watch?v=dDI7pecpo_o

Title: Re: Vunderfoil
Post by: Admin on December 13, 2022, 11:27:53 PM

Admin, how did you go about choosing Fusion-360 as your tool for this endeavor?


Hope that helps :)

Thanks burchas, it all helps!

We use Fusion 360 at work for product design, so we are already paying for it :)
 
I like to gripe about it, but it is also amazing.  I will check out Rhino for sure.  It looks like we can import our files for use with their plug ins.  That would be really cool.
Title: Re: Vunderfoil
Post by: tarquin on December 18, 2022, 11:04:00 AM
Messaged a couple of friends and they both said the same thing.
 If you can copy something accurately that works do it.
 Then decide what you want to change.
 That's when it gets difficult. You can't just make a foil longer or shorter etc. You have to change the chord.  Don't waste money on CFD until you really know what you are doing and get the most out of it as well. So I was wrong there.
 So in general it looks like you are on the right track.
 Then the build is important. No point spending a fortune designing something that flexes or twists. Again you are on it .
Title: Re: Vunderfoil
Post by: Admin on December 18, 2022, 11:10:56 PM
Messaged a couple of friends and they both said the same thing.
 If you can copy something accurately that works do it.
 Then decide what you want to change.
 That's when it gets difficult. You can't just make a foil longer or shorter etc. You have to change the chord.  Don't waste money on CFD until you really know what you are doing and get the most out of it as well. So I was wrong there.
 So in general it looks like you are on the right track.
 Then the build is important. No point spending a fortune designing something that flexes or twists. Again you are on it .

Thanks Tarquin,
I really appreciate it.  It sounds like you have a group of sailors at he forefront of sail foiling there.  Those guys (AC and similar) are on their own in designing foiling gear.  I am amazed by what they have accomplished.  The more I dig in to this the more I realize how unique our foiling actually is.  Our center of gravity is in constant motion, pumping very unique, and each discipline is its own design sphere.  I will look at a CFD but I expect a steep learning curve there as well.  Garbage in...
Title: Re: Vunderfoil
Post by: Admin on December 22, 2022, 08:56:41 AM
This is a 425 that I worked up this morning in Fusion.  Sadly, I can't print it in a single piece, so I cut it up a bit for easier and more accurate gluing before it goes to prepreg.  I can hear it printing in the background in PA-CF 🙂.   I did a 360 yesterday in a single piece that weighs 36 grams and is rideable as is.  For the larger front wings I am going to keyhole the joints so they slide-lock together during gluing and before prepreg.

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/321640083_3386660554948238_1094178663003674562_n.jpg?_nc_cat=109&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=WL-V0QzLgfcAX9sZIPK&_nc_ht=scontent-sea1-1.xx&oh=00_AfBOOZuUofVGu57DuOKRi_-dV0jb2vSkz5QIJVsXWA8b1g&oe=63AA2CC7)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/321547131_1514215419055272_2766801942220940898_n.jpg?_nc_cat=111&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=LonGPlcELUwAX-M1zeA&_nc_ht=scontent-sea1-1.xx&oh=00_AfBjJURgnrnqw_PT_7gSh2hDNr9KyUGXqU-1heOn14BI_g&oe=63A9617D)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/321580343_3324141094494584_2231261957222226504_n.jpg?_nc_cat=109&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=Nj92tLxe9joAX85OogU&_nc_ht=scontent-sea1-1.xx&oh=00_AfC9LN4tyLDPBB0XaBTwVfYzEiFEOB1Cz9M37XzDp87ehg&oe=63AA55B5)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/320705249_872565673879487_139172665819666949_n.jpg?_nc_cat=104&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=082F_w0h-xYAX-bQ8C3&tn=DHzk3JPtKj3-RU62&_nc_ht=scontent-sea1-1.xx&oh=00_AfAaa0IxYzIYYv5-jL37GDKEPaV5cGPUOBXcsgLebVw3JA&oe=63A95631)



Title: Re: Vunderfoil
Post by: Admin on December 23, 2022, 02:57:48 PM
Here is the freshly printed core, just out of the printer still up on supports.
(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/321718691_675054640979519_8460670461301627811_n.jpg?stp=cp6_dst-jpg&_nc_cat=109&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=gujsYMby9kcAX9B4K3r&_nc_ht=scontent-sea1-1.xx&oh=00_AfCo_xFmOKUzVIK3qrr6XgFDiNhIuwXrwlQHo7mgczmY5g&oe=63AA73AB)
Title: Re: Vunderfoil
Post by: PonoBill on December 23, 2022, 04:02:48 PM
Well, I made an eyeglasses case and a hinged box, so I've caught back up to about where I was three years ago.
Title: Re: Vunderfoil
Post by: Admin on December 23, 2022, 10:58:40 PM
Well, I made an eyeglasses case and a hinged box, so I've caught back up to about where I was three years ago.

This is actually a terrible time for you to be stuck over there in Bora Bora.  Enough basking already, I need you back in the USA, and quick.  We have foils to build and I have a zillion questions for you.

This little magic Bambu box that you suggested is outrageous.  I love it.  Possibly to an unhealthy level.  Still working on best settings, and of course the actual prints have pointed out spots where I need to improve the files.  2 steps forward, 1 st...or is it... 

Right now I have set the pedestal max width at a diminutive 12 mm in preparation for your blade fuselage.  Please send me a sketch of what you have in mind for that.  Flex is really uncharted territory for our sports but It is really interesting.  The effects of wingtip flex on vortices is fascinating.  It seems like the current thinking is flex=bad but that doesn't seem universally true for all component parts and may offer great benefits if well considered. 

This whole project has my mind lit up.  I love that feeling.  I finally have given in to Fusion 360's parametric timeline (which I have always dreaded).  The ability to change things in the past and have those changes alter all downstream changes is trippy in itself but it used to blow me up in a lot of scenarios.  now, with AI (deep learning, whatever we call it now) it intuits my desired result remarkably well. So freaking cool. 
Title: Re: Vunderfoil
Post by: PonoBill on December 24, 2022, 08:39:49 AM
Yeah, I reset my Fusion 360 skill level to less than zero when I wandered off to do electronic stuff two years ago, but the key to Fusion is parametric design. The first thing I do is figure out the parameters, including any offset for designing multiple parts. Using a construction line with a specific dependent length parameter (like length *.1 of the first part) to create points that you can use as constraints keeps parts from colliding when you make them bigger. You don't need to know the values, though you need to plug in a guess. Another key is deciding which parameters are dependent (can be calculated from other parameters). And then setting constraints as you draw. You've obviously figured a lot of this out, but defining parameters is a huge timesaving. It all but eliminates having start all over when you fucked something up. Especially when, as you point out, you go back in the timeline to rework something. Or just change parameters to change the scale.

I need to pick an effort and stick with it. I'm relearning Fusion 360 at the same time that I'm trying to make InfluxB (a time-series database) work with my Node-red and MQQT embedded systems projects. And I'm replacing the microinverters in my PV power system, and of course, getting in the water as much as possible.

I have to admit, I feel a bit constrained here in Bora-Bora, and I'm not really going to be unhappy to leave early so Diane can get her knees replaced. I've gone so far as to suggest she move up the schedule. This stuff is fairly thrilling. The entire print-to-ride concept is nuts but doable.

The fuselage I've been envisioning is pretty simple--slender bars in either a T or 90-degree X cross-section with the edges tapered to decrease drag. I thought we'd be building it up from carbon bar stock, but we could certainly try printing it. If that doesn't work it could be easily molded, either prepreg or carbon forging. The T would be easy to tune for horizontal and vertical flex, and X would add torque tuning.  Your plugin wing idea would work well with both, though I think that might be more suitable for the tail and look for a way to plug the fuselage into the front wing directly into whatever added wing structure holds the mast. Probably just a bulge like I think you were considering for the mast location for the Axis advanced fuselage.

Yeah, the Bambu Labs printer is remarkable. I'm stuck here with a funky old Prusa printer that feels like an old flip phone compared to an iPhone. The core tech still works, but that's all.

Oh, and flex is inevitable. The earth flexes when we walk on it. The distance is probably around a planck length, but when you apply a force everything flexes. Theoretical bullshit aside, I think what we need to do is decide where and how the flex occurs. Obviously aircraft wing designers have to include flex in their designs, anyone with a window seat in a commercial jet has seen that. The difference is just scale.
Title: Re: Vunderfoil
Post by: PonoBill on December 24, 2022, 09:08:02 AM
I just showed Diane your work. She compared it to my eyeglass case and gave me a special olympics hug.
Title: Re: Vunderfoil
Post by: Chan on December 24, 2022, 12:16:01 PM
I have to admit, I feel a bit constrained here in Bora-Bora, and I'm not really going to be unhappy to leave early so Diane can get her knees replaced. I've gone so far as to suggest she move up the schedule. This stuff is fairly thrilling.

I just picked up the Winter issue of the gorge magazine featuring an article on Winter SUP which has a classic picture of of you leaning in to check out the weather forecast up on the monitor at Big Winds, taken by the multi-talented Jennifer Gulizia (see pg 41).
Title: Re: Vunderfoil
Post by: PonoBill on December 25, 2022, 12:15:17 PM
You may have seen this video, I doubt you'll be printing multi-color santas but the ability to control up to 16 filament choices automatically and precisely select where each will be used in the slicer is simply insane. I'm wrestling with getting a Babu Labs printer for Maui. It's silly to do that, but what the fuck. Some of the stuff I print has extensive support. Using something like Polycarbonate for support guarantees you'll spend a lot of time with an exacto and sandpaper. Printing support filament, either breakaway or soluble, is an incredible feature. For that matter switching out filaments to take advantage of other mechanical properties would be interesting.

For anyone wondering why the Bambu Labs printer is so exciting when they can print perfectly well with their 200-buck Creality Ender, take a look at the level of tech in this printer. Fucking amazing. I'm surprised that the general 3D print world isn't going nuts over this, but I know a lot of people have spent a lot of time optimizing what they have. It's a Ford 1990 F150 vs Cybertruck.

https://www.youtube.com/watch?v=QyS_1TZ9OPI

Title: Re: Vunderfoil
Post by: Admin on December 25, 2022, 01:10:00 PM
Here is a reverse engineer of an Axis tail to get the pedestal right for tails.  I started with a scan, matched the profile and outline and tugged a little.  I will set the height and incidence  and then run the top contours off of each individual foil so, this will act as our start template.  I printed this draft with super light infill (essentially hollow) in PA-CF, but even so, there is no way I can flex it by hand.  Ooooh! my tenderloin is done!
Happy X-mas guys!

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322317744_526282642855376_2167756914174365624_n.jpg?_nc_cat=105&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=u2PMdCVAcisAX-nBHkk&_nc_ht=scontent-sea1-1.xx&oh=00_AfDDxJN0t8nDBO10e3FDvvnFQgIDgNIQ5JuBLFu6kSZupw&oe=63ACE7C2)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322126923_716283013391596_4992450427593622014_n.jpg?stp=cp6_dst-jpg&_nc_cat=100&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=eUeWKwGcdGsAX9GWh2x&_nc_ht=scontent-sea1-1.xx&oh=00_AfCGg23arpcFrmkRDuaS6C3W00FzneDXrS8vFxJ3eJrWqw&oe=63AE50E9)
Title: Re: Vunderfoil
Post by: Admin on December 25, 2022, 01:19:30 PM
You may have seen this video, I doubt you'll be printing multi-color santas but the ability to control up to 16 filament choices automatically and precisely select where each will be used in the slicer is simply insane. I'm wrestling with getting a Babu Labs printer for Maui. It's silly to do that, but what the fuck. Some of the stuff I print has extensive support. Using something like Polycarbonate for support guarantees you'll spend a lot of time with an exacto and sandpaper. Printing support filament, either breakaway or soluble, is an incredible feature. For that matter switching out filaments to take advantage of other mechanical properties would be interesting.

For anyone wondering why the Bambu Labs printer is so exciting when they can print perfectly well with their 200-buck Creality Ender, take a look at the level of tech in this printer. Fucking amazing. I'm surprised that the general 3D print world isn't going nuts over this, but I know a lot of people have spent a lot of time optimizing what they have. It's a Ford 1990 F150 vs Cybertruck.

https://www.youtube.com/watch?v=QyS_1TZ9OPI

Yes, what a device!  It really blends the whole development process into one seamless thing.  The AMS is killer as well.  It is really well sealed (actually hard to open) so no humidity issues for spools.  Plus if a spool runs out it hot switches straight to the next.  Great suggestion buddy!
Title: Re: Vunderfoil
Post by: PonoBill on December 25, 2022, 05:19:16 PM
I should have realized you'd have the AMS since that's the only one they sell directly right now. I should have known from your wing pictures since there is clearly another color under the wing for the supports. I don't know if you're using support filament, but if you aren't, you should. I breaks away cleanly. You can even get support filament that dissolves in alcohol, as it does with my ancient but very high res SLA printer. 

I bought my Bambu on Kickstarter, cheaply, but it doesn't have AMS, though I can semi-manually switch filaments in mid-stream. The one I just bought for Maui has the four-spool AMS included, as yours undoubtedly does. What blows me away is that they have multiple AMS boxes integrated seamlessly. I surely don't need that, but the ability to retrofit, even with my Kickstarter version, shows the level of design expertise. I can add AMS to mine as a bolt-on modification that is remarkably cheap.

My Prusa here in Maui is making a mess of print jobs, with blobs and hickeys everywhere. Part of the problem is the cheap-ass SD cards I was using. There's really no such thing as a curve for most printers, and most cad software. It's all polygons. The printer stores the next twenty or so sections of the polygon to be printed in a queue. If the queue runs out the printer pauses, but the filament is still under compression so a blob comes out of the print head. A slow SD card can deplete the queue if the print includes continuous curves at high resolution. So I got better SD cards and I still had some. It turns out that the feature that lets the printer resume after a power outage has to write the queue to the card frequently. So I turned that off and now my prints are nearly half as good as the Bambu Lab prints. So yay, success, only took me two days to figure out a problem that will never cost you failed prints or time (other than the time required to read my whining).

I do have the quite expensive AMS for my Prusa printer. It totally sucks donkey dicks. I spent almost a week trying to get it to work and the only reason I didn't throw it against a wall is that it was so fucking expensive. It's sitting in it's shipping package under my Prusa, waiting for me to try again. Not happening. After seeing how the Bambu Labs AMS works it's clear to me that this thing does not have the tech to pull this off.
Title: Re: Vunderfoil
Post by: PonoBill on December 25, 2022, 07:16:03 PM
another worthwhile Bambu AMS video:
https://www.youtube.com/watch?v=QyS_1TZ9OPI
Title: Re: Vunderfoil
Post by: Admin on December 26, 2022, 12:35:05 AM
Yeah, the AMS is so cool.  The maths are strong with these Bambuers.  That yellow stuff in my image above is Bambu's "green" support filament.  I am stoked that you have the AMS coming so we can work out best practices for foils.  Foils actually bring some interesting hurdles.  This printer is insanely smooth on vertical or high degree surfaces.  It is also perfect on horizontal.  It is the least smooth on near horizontal (but not horizontal) curved surfaces.  You can get great results still but with really fine settings for everything and a lot of support.  That takes time, however.  The printer needs to change filament a lot and needs to purge the last filament.  This does lead to really scary looking little gremlins that come out of the waste chute.  Aside: I would strongly suggest leaving a few of those in choice locations around the home (under pillow, in a mug, etc) to terrorize the unsuspecting :).  I really need to work on niceness.  Break Aside: The other complication is that tail foils hate to stand still when vertical, even in parts.  They are so thin.  The do great until they get tall and then the prints get whacky.  We need to work out the best balance of brim, raft and support to make that work well.  Also the release stuff works best on coarse prints but wants to hold on really smooth surfaces.  There are a lot of settings there that I haven't explored yet.  Tech support says, "have fun to try, joy of printing is love to explore!"
Title: Re: Vunderfoil
Post by: Admin on December 26, 2022, 01:39:40 AM
Here is a reverse engineer of an Axis tail to get the pedestal right for tails.  I started with a scan, matched the profile and outline and tugged a little.  I will set the height and incidence  and then run the top contours off of each individual foil so, this will act as our start template.  I printed this draft with super light infill (essentially hollow) in PA-CF, but even so, there is no way I can flex it by hand.  Ooooh! my tenderloin is done!
Happy X-mas guys!

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322317744_526282642855376_2167756914174365624_n.jpg?_nc_cat=105&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=u2PMdCVAcisAX-nBHkk&_nc_ht=scontent-sea1-1.xx&oh=00_AfDDxJN0t8nDBO10e3FDvvnFQgIDgNIQ5JuBLFu6kSZupw&oe=63ACE7C2)

(https://scontent-sea1-1.xx.fbcdn.net/v/t39.30808-6/322126923_716283013391596_4992450427593622014_n.jpg?stp=cp6_dst-jpg&_nc_cat=100&ccb=1-7&_nc_sid=5cd70e&_nc_ohc=eUeWKwGcdGsAX9GWh2x&_nc_ht=scontent-sea1-1.xx&oh=00_AfCGg23arpcFrmkRDuaS6C3W00FzneDXrS8vFxJ3eJrWqw&oe=63AE50E9)

PS: The outline I used is NACA 24, the profile is the lower half of NACA 12.
Title: Re: Vunderfoil
Post by: PonoBill on December 26, 2022, 07:49:37 AM
That's very cool, I have a KD tail I want to try (carved out of G10) and I'm planning to do that myself. I need to figure out the contour of the tail, but that's not too hard.
Title: H105
Post by: PonoBill on December 28, 2022, 04:16:35 PM
I like the looks of this foil. I'll see if I can get the .dat file for it.

Title: Re: Vunderfoil
Post by: PonoBill on December 28, 2022, 04:24:14 PM
I've been doing a lot of digging and reading. The idea of plugging the mast into the rear of the main wing has a lot more merit than just eliminating a structural fuselage. If the mast came into the entire wing it would create intersection drag. Not a huge issue but nice to avoid. Staggering the mast back towards the rear of the wing and adding a little fairing area behind the actual chord of the wing should eliminate most of that drag. The biggest issue is having enough material so the junction is strong, but I'm reasonably certain we can do that.
Title: Re: Vunderfoil
Post by: tarquin on December 28, 2022, 10:33:49 PM
The NACA 63-412 profil has been used a lot in the past.
http://airfoiltools.com/airfoil/details?airfoil=n63412-il
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