Add-in announcement: Hydrofoil and Airfoil Tools. Seeking your feedback / ideas

[OceanHydroAU]

My decade of work in water and airfoil optimisation is now a Fusion 360 Add-in.  To begin with, I'm supporting:

• Wings (lifting foils) and Struts (low-drag symmetric foils)
• Cowlings (low-drag shapes for the nose or tail of anything in a flow)
• Propellers and Turbines, to be driven by a motor, or collect energy from flow
• Ducts suitable for use as a Propeller or Turbine shroud.

The Add-in collects the necessary information about the scale, medium, power, and/or expected conditions from you, and parametrically inserts the ideal shape best-suited to your intended purpose.  "Ideal" is based on thousands of hours of CFD simulations and particle-swarm genetic optimisation for popular use cases, and typically out-performs legacy shapes (e.g. the best in the UIUC database by 10% to 100%, and all NACA shapes by 57% to 120%).  Also included are facilities to perform specific optimisations for your exact needs, along with a suite of other tools.

This forum posting is here to solicit user (or potential users) suggestions, feedback, and comments, and also for bug-reports a help and feedback forum for users.  For anything not suitable for public, I use gmail - my address is the same as my username on this forum - feel free to write to me directly.

IMPORTANT: If you need or work with airfoil or hydrofoil shapes, please have a think about what you would hope to see in this Add-in: as a programmer, it's vastly less expensive and time-consuming to accommodate future user cases from day one.  If you want something, and can't see that we already do it, now is your chance!  Let me know immediately, so I can be sure it's included in future.

The general operation is as follows:-

• Select what you want (wing, strut, prop, turbine, cowl, or duct) - which also defines what "optimal" means (e.g. best L/D for wings, lowest drag for struts)
• Decide where and how to place it (select points or lines in 2D, or paths and planes in 3D) which also defines the size and direction.  Chose an optional center-of-moment point to auto-position for ideal angle-of-attack (which differs as a function of use conditions)
• Specify you medium (Air, Water, or other) and its property ranges (temperature, altitude, depth, salinity, turbulence)
• Specify your operating conditions: i.e. Speed range and surface finish (rough or smooth)
• Supply power details if relevant (input for propellers, or output for turbines)

The Add-in will insert foil points connected by spline or loft, and optionally also construction elements you can reference in your design (e.g. moment centers), parameter variables you might need to use, and reference polar diagrams and power charts etc that save with your project.

If you change your drawing (e.g. make a wing bigger), the new foil shape will be automatically re-computed and all data updated, so you can be sure that your design will always contains best-performing shapes no matter what you change.  e.g. Models and Full-scale built from the same Fusion 360 project should generally both "just work".

This is a project likely to remain under constant development.  Subscribe to this topic for updates.

Over to you!  Do you need something not yet thought of here?  Do you have a project you think this would be useful for?  

Please click "like" if you would use this tool - so I can get some idea of how many people I'm doing this for!

[OceanHydroAU]

Hi @Anonymous - I'm still struggling with porting my solver, but it runs fin in Linux.  If you turn on your "text commands" window, you can see some useful information about the foil it inserts (best AoA and the L + D + L/D details for that).  Feel free to send me a copy of that text (right-click, select-all, copy) and I can send you back the data from my linux solver if you like.

I've almost finished coding the import and the export menu functions now - where "export" lets you select any airfoil shape to save to a .dat file, which you can then run through any airfoil program of your own (while you wait), plus I should be able to add a "cloud performance" option easily now, so I can use my linux solver to get you your data direct from the menu.

Remember to "vote" for the option you want the most - I do look at the number of users who have done that for prioritizing my effort!

(Previews:)

ExportImport

Chris.

[ludde94]

Hi! First of all, a massive thank you for this amazing plugin!

Ive been playing around with it for some days now and I'm blown away by the possibilities.

Just have some problems with the "Create Propeller" feature, it gives me an error message, I'll link it here. 

The turbine feature works great tho to create propellers but I would like to be able to specify power etc. 

Do you have any plans for further development?

Thanks again! 😊

[OceanHydroAU]

Hi,

Thanks for the encouraging feedback!  I'm using my own plugin for assorted things almost every day now, and yeah - I'm quite happy with how well it works so far.  Sorry you hit a snag on that turbine!!  I made the questionable development decision to allow users to select any orientation they like, but the resulting math of having to deal with wrapping and bending and translating stuff in any arbitrary input plane they up a code nightmare - so I'm in the middle of a complete re-write-from-scratch on that front.

You cannot use the turbine feature for creating driven propellers - sorry (well, you can, but they'll perform very badly) - the airfoil sections would be all backwards, and the Reynolds numbers all wrong (turbines slow down the flow, propellers speed it up).

Propellers were the ultimate reason I've been working on this plugin, FYI, and I have so far worked out everything I need for creating them "perfectly" and coded the UI for this.  I've been trying to keep it as simple as possible by getting things the user knows or can easily find out (speeds, heights, medium, etc) and working behind-the-scenes to convert them into the stuff I need (densities, reynolds numbers, helical translational velocities, etc).

My plan for the UI is below - not everything I've got there is required for the user to type in (once they enter some things, that's enough info for me to auto-calculate other things so they don't need to enter it all) - but it's still a pretty big list.  Do please take a look and let me know if you think anything is missing (or could be better explained!)

 

Besides props, as I said in an earlier post - I'm re-writing the turbines (which are way easier to make - vastly fewer variables to juggle) and also in the middle of an import and export option.

On the shapes-front, I'm re-optimising everything using control-point splines (Autodesk release their long-awaited API support for these just today!), building an entirely new database of struts (so you can select the thickness you need), and adding custom support for about a dozen carefully selected Mach numbers - that's all pretty slow: I've only got 200 CPU cores I can affordably use, and it's about a day's CPU time for each shape.

My optimiser (which runs on linux) is able to take custom input - for example - to find sections which perform well at more than just 1 operating condition (e.g. props at cruise and max speed), or which have unusual characteristics (e.g. I'm experimenting with a symmetrical section for ornithopters - so it provides good lift for both up and down strokes) - anything is possibly really - but I've got no idea how I build a user interface to let people explain that easily  (it is on the drawing board though).

What's your interest in props?  Are you building a big or little ones?  Is it for air or water?  

[OceanHydroAU]

I've had a few people ( @mmharris , @ludde94 ) ask how to use my turbine beta feature - it creates the turbine OK, but there's a minor bug - it doesn't put it where you asked... while I fix that, here at least is a demo so you can use what's working right away:

https://autode.sk/31rPmsn

 

[ludde94]

One feature that would be nice to have in the airfoil feature would be a wing calculator based on two profile, root and tip, with a specified distance apart. Where you specify the speed you want and also the lift.  Somewhat like you can do in the Xflr5 and get an alfa range for what angles you get the desired lift from the wing. 

Might be difficult to create, but since you're able to create the crazy propeller and turbine features it might not be impossible.. 😅

Thanks again for the last update! Im making a small foiling pedal boat, carbonfiber foils and hull. mainly based on the data I get from the Xflr5 but yours is so much more user friendly! Great work! 

[OceanHydroAU]

Cool project!  Have you seen the Manta5 ?  I measured their rear foil to be about 0.5 square meters in area (it's 6.5ft wide I think they said).  I've noticed that you get better lift for a lot less drag with larger chords (disregarding tip losses of course) - so they'd gain 14% better performance just from picking a better shape (e.g.  https://a360.co/3dRK3HO ) - assuming a shorter wingspan doesn't ruin balance. (I even printed some to check...)

It looks from the section they've selected (their photos are a bit hard to see - white foils on white background) that they didn't pick the best either (it's more strut-like than wing-like) - so they could probably also get 100% better performance just by fixing that.

Have you looked at https://www.aeolus-aero.com/ ? He's done similar stuff to me - except I'm concentrating only on section shapes at the moment (which Uwe has not done at all), however, he *has* done absolutely everything else as it pertains to 3D shape optimisation.  If you used my sections in his shapes, I think you'd get the best possible outcomes right now!

I do have plans to support 3D in future (you might have noticed the the icon for "insert wing" is different if you're not in a sketch...) but for now, perfecting the 2D parts is taking more effort than I realized.

My plan for the specific feature you mention is slightly different - you will draw the "surface" (flat or curved) to represent the outline of the wing you want, tell me stuff like speed, weight, medium, etc etc... and my software will convert the surface you've specified into a wing, selecting the correct airfoil shapes for every different chord you've got (and, if you did something odd, like a flying cylinder, the upright sides would be low-drag struts, not lifting-shape wings, etc).

Or, long story short - it's easier to give you the "best" for what you need, than try to work out how "well" something approximate that you specify might work.

You might be interested to note that I've spent all weekend so far working on marine propeller optimisation tests (real, in a river) so when I finally get around to finishing the propeller component of my work, I'm confident you're going to be nicely impressed 🙂

[jarosascordova]

Hello,

This tool seems amazing and I am certainly looking foward to using it in my uni projects, would it be possible to add .DAT file import capabilities to the add-in?

Thanks alot for this awesome contribution 🙂

[OceanHydroAU]

Yes, it does import and export - but you need the beta version for that - link is here: http://chrisdrake.com/Airfoil_Tools/  - I posted screenshots of this yesterday:  https://forums.autodesk.com/t5/fusion-360-design-validate/beta-testers-wanted-for-my-add-in-airfoil-...

Besides reading (and, optionally, automatically repairing) any kind of airfoil data file in any known format (or even just excel CSV), it also includes options to re-spline the input to your specifications, set minimum thicknesses, scale and join to your chosen location, rotate arbitrary amounts, flip it, add constraints, wrap it all around some axis (e.g. for rotating foils, like propellers), and insert elipses (useful for wingtips to have nice ends).  It even supports Degree-3 control-point-splines (probably nobody uses these except me, but they're essential for genetic optimisation because they resist looping).

It also does export too (thus, if you export anything, you can then do all the above when re-importing it!)

I'll be submitting this update to the production version after it undergoes more testing (I've done loads so far, and it all works, but needs checking on Windows - I use Mac mostly).

Import AirFoil .dat files using Airfoil Tools for Fusion360

[jarosascordova]

Hey, thanks a lot for the info and for your awesome work. I am a Windows user myself and I'd be glad to help with testing if you need to 🙂

[Anonymous]

I'm very grateful for this plugin - I've been trying for a while now to design parts for small-micro RC aircraft for 3d printing, but even after running the numbers through a monstrous excel sheet generating the geometry by hand in fusion 360 is a painstaking process. This makes everything almost trivially easy!

I've had a problem with the latest build, v1.20201117 db-494 when I try to generate propellers for a ducted fan model; the 'ok' button remains grey, and the 'help' box reports I still need to supply a Reynolds number. I'm not sure if I've misunderstood how the model should be arranged, or if there's a bug in the UI.

My sketch is 3d, with a 15mm line from (0,0,0) to (15,0,0) for the centre line. The end point at (15,0,0) is used as the nose point. The tip location is a 10mm line from (0,25,0) - e.g. 25mm tipward of the rotation axis - to (0,25,10) (I've also tried (10,25,0)).

I'm using the following parameters:

Nickname: Test1

Conditions:

    Medium Air

    Flow Turbulent and dirty

    Smoothness Very rough

Velocity Range:

    Target 40 mps

Altitude Range:

    Target 100m

Temperature Offset Range:

    Target 12 C

Creation Strategy:

    Inside Duct

    Blade shape formula:#

Constraints:

    RPM: 40000 rpm

    Tip Speed: [blank]

    Blade Length: [blank]

    Blade Count: [blank]

    Pitch Variation: [blank]

    # of sections: 12

    Min thickness: 0.5mm

Input Motor Power:

    Cruise: 300w

    Max: 450w

Input Motor Torque:

    Cruise: 0.05 N m

    Cruise RPM: 30000 rpm

    Max: 0.065 N m

    Max RPM: 40000 rpm

    Reduction: 1 : 1

Target Thrust:

    Thrust: 3.0 N

[kursat.uvez]

Awesome work. I have been using it since the initial release to make hydrofoil

struts/wings, 3d printed them and  have been using them

Quick question, I've copied the latest development bundle over the installed version
I've got from the app store. It seems to work. It shows the version to be 

  v1.20201122 db-499

The directories seems to be different than the youtube manual installation video, so I 've chosen to copy over it.

Would that be a usable installation?

Or is the youtube manual installation still valid for the development/beta bundles?

[OceanHydroAU]

It is programmed to work from wherever it finds itself installed - so you should be good to go!

I'm about to issue an update to all users - since I've just finished doing propellers and turbines too.  There's assorted minor bugs fixed, and a monster pile of new features added as well.

I'd love to hear your thoughts (and experiences!) with hydrofoils - I've designed a few dozen now, and printed 3 so far (for other people, all still out being tested, but early results are promising).  I assume you're doing the main wings, right?  Maybe also the stabiliser?

What strategy are you using for your design criteria?  I printed a *huge* SUP-foil based on designing it for best lift with minimal drag at very slow speed, which in retrospect might not have been ideal - you need good lift, but not the *best* lift for the launch step, nd probably need the ideal L/D at some *faster* speed for when you're up and foiling? 

Are you using struts for the stabiliser (zero lift: not foils) ?  It makes sense to me that the two wings do not fight each other.

What kind of 3D printing are you doing?  I've just added parting-line features for a hydrofoil manufacturer who's doing pre-preg carbon fibre, while I myself am just using FFF and wrapping that PLA in fibreglass.  I've just gotten a huge CNC to start milling foam blanks for larger and faster output though...

[OceanHydroAU]

Hi,

I have literally just finished the propellers now - the current beta release (1.20201129) has them in and working.  (I've only done minimal testing so far though.)

Here is a paramotor blade:

Remember, since the sections are bent to go in a circle, you must use the Surface Loft feature to make my output sketch into a working prop:

(you then patch the ends and stitch it all to turn it into a solid)

Best of luck with my chord formula malarky - I decided to let everyone do anything they like with blades (scimitar rakes, crazy chord transitions, hedral, and more...) which is creeping into rocket-science territory (ha ha - almost literally) - e.g. here's my formula to emulate the chord of an existing prop that I want to compare my output against (the photo above):

[ ((68-10*(( u <0.183)*( u >0.126)*(( u -0.126)/(0.126-0.183))))*( u <=0.183)+( u >0.183) * ((sin( u -0.183+1.4)-0.8)*5*39+42)) /1000 , -chord/2]

just shout out if you need help.

[OceanHydroAU]

I've had 200 CPU cores chewing on performance optimisation for the last few months - below is a couple of fascinating charts (the same chart really, plotting Re .vs. Mach then plotting Mach .vs. Re).

I was asking myself the question: "What's the best speed for the tip of my paramotor propeller?" - well - as you know, air is compressible, so it behaves differently as you go faster.  It turns out that as you head past mach 0.5, things get very messy - airfoils that even work properly at all get harder to find, and the ones that are found do not work as well, if at all.  Moving up to mach 0.57, only half of the Reynolds numbers I'm using find any foils that work at all, and past mach 0.65 there's none.   So - don't go faster than half the speed of sound on your props!

As for what the *best* speed is, serious performance degradation kicks in from about mach 0.3 up... so it looks like slower-spinning props which have larger blade chords are probably going to be much more efficient...

Struts on the other hand (no lift shapes - not shown in the charts below) are much happier to perform their low-drag duties at higher speeds - all of them remaining pretty good upto about mach 0.65, with ones that still work being found at mach 0.9 even.

If you're designing props, and want to avoid tip vortices by using struts on the ends, that's great news.

Tip: your prop blade tip mach number shows up in Airfoil Tools when you pick your blade speed etc (not for water of course - it's not compressible).

 

 

 

[maccleery]

Airfoil Tool wings with 3D printable hinged ailerons that can print as one assembly!

I wanted to share back a technique we are using to add hinged ailerons to Airfoil Tools wing airfoils that can be 3D printed as a single assembly. This is inspired by the tutorial below on how to design 3D printable hinges.

How to design 3D Printable Hinges - Make moving parts!

Motivation? We are developing tethered wind turbines for electricity generation using the machine learning optimized airfoils in Fusion 360 Airfoil Tools. Electricity produced is roughly proportional to the lift coefficient cubed divided by the drag coefficient squared, so aerodynamic performance is everything for us. 

Being able to 3D print an entire wing assembly including hinged control surfaces like ailerons is a big deal. It will reduce the amount of work it takes to manufacture different wing airfoil designs for flight testing. We want to be able to 'snap in' different airfoil designs and test them in flight with the strain gauge measurements of the aerodynamic forces and torques. The goal is to add code to Ardupilot that automatically characterizes the airfoil polars (i.e. lift and drag verus angle of attack and airspeed) during flight using force measurements. 

Photos:

How does it work?

The main wing section is extruded with end caps and a solid hinge rod.

The moving control surface is extruded with a hinge tube that is printed around the hinge rod.

The complete assembly is shown below.

By including end caps on the control surface, no support is required to 3D print the entire assembly on its side, as shown below. In this case we are printing with a 0.8mm nozzle.

Instructions:

First you create a sketch for the wing chord, and insert the airfoil using Fusion360 Airfoil Tools.

Then edit the airfoil sketch, to add the following. The corresponding dimensions from the screenshot below are noted.

1. A circle for the hinge pin (7 mm). This will be attached to the main wing section.
2. A circle for the inner diameter of the hinge tube (8 mm). This will be attached to the moving aileron section.
3. A circle for the outer diameter of the hinge tube (12.64 mm). This circle can be constrained tangent to the upper surface of the airfoil and lower surface of the airfoil.
4. A circle or the outer diameter of the main wing section with airgap spacing from the hinge tube (13.64 mm).

5. Add the first extrusion for the aileron.

6. Next, airfoil sketch is copied to an offset plane to provide the end caps for the wing. The offset plane is located to provide a 1 mm airgap between the aileron hinge tube and the main wing end cap. Screenshots from the complete assembly are shown to clarify.

7. Next is the first extrusion for the main wing end cap, which is done from the sketch copied to the offset plane.

8. Then the solid hinge rod is extruded back to the original sketch plane.

9. Next the main wing assembly is mirrored and an extrusion is added for the center section, using the circle that provides the air gap around the hinge pin.

9. Now the aileron is extruded to the end caps. This allows the assembly to be printed on its side without support.

10. Finally, filets are applied to enable a greater range of motion for the aileron.

11. The range of motion can be determined by converting the main wing and aileron bodies to components, then adding a joint, adding contacts and then right clicking on the joint and going to "Drive Joint". In this case, the range of motion is 70 degrees. Iff a larger range of motion is needed, the airgap spacing and filet size can be increased.

12. Finally the aileron is rotated back to 0 degrees and the assembly is exported to STL for 3D printing as a single print.

The Fusion 360 source file is attached. 

[Anonymous]

Hi

Not many people would be interested but would it be possible to flatten the nose of a airfoil in Fusion to allow it to be mounted onto an already aero shape (Bicycle) and shape the airfoil in a manner as such in the photo attached above the rear wheel?

Thanks

Graham

[OceanHydroAU]

Hi, you could edit the spline points I guess, but it's unlikely to produce an optimal shape (the transition between the edit and the foil shape will upset the flow to some extent).

In my fairly broad experience, things that "look" airfoil, and are advertised as special etc, are usually fake - an artist has rounded stuff to make it look pretty, and the advertising people make up words to make it sound awesome.  It's not actually any ideal shape performance-wise.

The "correct" solution to reducing the wind resistance for a bicycle is to decide what minimum thickness tubes you can live with (or have already got) then find the optimal low-drag shape to accommodate that thickness at the speeds you want it to perform best at, then wrap the tubes you already have to make this shape (or make new tubes of the right shape to start with).

Airfoil Tools consists broadly of two parts - the one you use is the "front end" and runs in Fusion 360 to insert the "right shapes".  The other main part is the CFD optimiser, which runs 24/7 on all my servers working to create ideal shapes for the front-end to use.  I have done a "test run" for optimising shapes based on minimum thicknesses chosen by users which works nicely, but I've not yet incorporated a way to get those into the front end.

The problem is this...

I've got 2 kinds of shapes (struts and foils)

I support 64 different reynolds numbers

I support 12 different flow and finish conditions 

I support 24 different mach numbers

I allowed 12 different thickness-ratio selections.

That's 2*64*12*24*12 = 442,368 different shapes.

It takes one CPU-Day to optimize a shape

I've got 204 CPU cores

That's 6 years...

So I'm in the middle of working out how to connect the front-end to the optimizer with some mechanism to let users wait for the day it's going to take to create a custom shape, since it's going to be another 5 years before my pre-computed database is fully completed...

If you're interested, send me some dimensions (chord length, and thickness) and the speed to use, and I'll find the right shape for your specific use - if nothing else, you can compare it with what the industry is already doing to see how far off they are?

Sorting out wind resistance well make a big difference: https://youtu.be/bvmibwafGXc

[tony.clare]

Great tool that I'm just starting to experiment with. Thanks for you efforts. Really appreciated.

With the current version can you create struts to "hide" non-aerodynamic shapes? e.g. just staying in 2 dimensions for simplicity I'd like to be able to create struts where I specify:

1. chord, (e.g. 60mm)

2. minimum width at the widest point (e.g. if I was trying to hide a 10mm external diameter tube, and I could print to a thickness of 1mm I'd want the shape no thinner than 12mm at the thickest point)

Currently I can create an optimal shape with chord 60mm, but of course it won't be anywhere near wide enough to enclose the shape I'm trying to hide. Is that something I can do now but I haven't figured out, or is it coming soon in Create Cowling?

Thanks again. 

[tony.clare]

I just read your most recent answer to the previous question above again, and I suspect it's also the answer to my question. Apologies if that's the case.

[OceanHydroAU]

Current version - it does not yet have a "thickness" specification for you (sorry!).

My back-end optimiser does have a "thickness" switch though, and I have processed a range of foils to produce an interim dataset with the following 12 thickness ratios:

0.05  0.1  0.15  0.2  0.25  0.3  0.4  0.5  0.6  0.7  0.8  0.9

(e.g. 5% to 90%)

... so what you're after is in my pipeline.  

Meanwhile - I'm happy to whip some up for you - let me know the details (medium, speed, etc) and I'll generate some for you.  If you like - just create it in Airfoil Tools and give it a distinctive name, and click the "share" option, then tell me what that distinctive name was and I can find all the data in the logs.

My "import" option can be used to load files, so I'll send you some.

I've just spend $10k on a new 128-core EPYC server, so hopefully I'll be able to get a much-more-useful inbuilt database shipped so everyone can get a lot closer to what they want immediately.

Also on my to-do list is some way to get this stuff automated - pre-computation is nice, but there's too many options I cannot do, so I need to give my users the option to get "exactly" what they want, and wait the day it's going to take to build the CFD-perfect shape for them...  (and yes, I'm annoyed I didn't think of that from day 1 ... it's obvious in retrospect... but more hard work now to retrofit).