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

94 REPLIES 94
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Message 1 of 95
OceanHydroAU
17481 Views, 94 Replies

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

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.

 

WIP_Screenshot.png

 

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!

94 REPLIES 94
Message 61 of 95
OceanHydroAU
in reply to: OceanHydroAU

I am preparing an update right now as it happens.  I fixed a few bugs - the worst one (so embarrassing) was this:-

 

Oops:-

 

speed_loss_factor = dlg['target_efficiency'+aft].value/100 ** 0.5 

 

Fixed to:-

 

speed_loss_factor = (dlg['target_efficiency'+aft].value/100) ** 0.5 

 

... blows my mind that it somehow got past my release testing...  anyhow - the outcome of that was blade angles would not be absolutely perfect, and in worse cases might be a long way off.  For turbines - the betz limit is that factor, FYI.  e.g 2m/s inflow becomes 1.53622915m/s outflow:  energy = .5 times density times area time velocity squared; so the resulting speed after removing 59% of the energy must be e=e*sqrt(energy).

 

I've also added a year of more effort into the foil selections (especially relevant for props and turbines) which is now also included.

 

To manually update, first ensure you have the latest version:-

  1.    in the "settings" submenu of "airfoil tools" itself, click the "check now" box
  2.    then close the menu and re-open and (if it says) click the "update now" box.
  3.    redo above until there is no more "update now" box

Then update the main program:

  1. find on your mac or PC the file "AirfoilTools.py"
  2. get the update from http://chrisdrake.com/Airfoil_Tools/check_update.asp/20220218/AirfoilTools.py
  3. and replace the AirfoilTools.py with the update
  4. restart AirfoilTools (shift-S, add-ins, AirfoilTools, stop, run)

My code currently only makes a blade - it will be up to you to decide the hub diameter, number of blades, etc.  I do have future code which handles that math and practicalities for you, but it's too wobbly to release right now.

Generally - my blade will extend as close to the rotation line as it can - which should usually be closer than your hub diameter - so you should be able to just delete the inner profiles that you don't want.

 

If you're struggling - don't pull hair - just let me know as much as you're allowed to, and I'll walk you through it.

 

Note: I've only partly tested the new update - so if anything fails, let me know (and, if it's OK, please allow the "share errors" option to be on, so I get a copy  of what broke at the same time).

Message 62 of 95
OceanHydroAU
in reply to: OceanHydroAU

Disregard the above instructions; I attempted to back-port the bug-fixes to the previous stable version, and created a monster.

 

Better to use the current beta which at least creates propellers properly (albeit with a *very* picky interface) and has assorted other new things.  Grab the "development snapshot" (Currently Airfoil_Tools-2022_02_19_19h42m08_rel.zip ) from here: https://foils.pro/Airfoil_Tools/

 

Props and Turbine MUST be created using the method shown here (3D sketch, exactly how I do it).  In future, I'll fix that so you can create them in any orientation on any plane... but for now - just copy how I screencasted it:   https://autode.sk/3oD7OXZ

 

*IMPORTANT* - you must create any useless fit-point-spine as well, and select that as the "blade outline" (which will be ignored) - I'm in the middle of letting you "draw" how you want you blade, so my math can give you the shape you want, without you having to be a math-formula genius.

Message 63 of 95
OceanHydroAU
in reply to: OceanHydroAU

I've shipped an update. It fixes a range of minor bugs, like imported-foil minimum thicknesses, calculation of flow speed change through props and turbines, and a range of edge-cases that threw errors.

 

It now includes an option, enabled by default, to source foils from our web service in preference to the inbuilt database, since this database has grown at 67gb making it impractical to ship to everyone.

 

Next time you start Airfoil Tools and open any menu on it, you should be offered the update.  To get it immediately, click the "Check Now" option in the "Settings" menu, then re-open any menu to update.

Message 64 of 95

i cant get the propeller generator to work (see pic) i am not sure how to fix/get to work

Message 65 of 95
t1WS6SD
in reply to: tommyschnettler

Good afternoon. I have exactly the same error. Have you found a solution?

Message 66 of 95
t1WS6SD
in reply to: OceanHydroAU

Good afternoon. You have a great app. You have put a lot of time and effort into it. Can you explain how to work in fan blade creation mode. I get an error when selecting contours - once the selection worked, but then the selection error appears again. What is it and how soon can you fix it?
Sincerely.

Message 67 of 95
OceanHydroAU
in reply to: t1WS6SD

Sorry for the delay - I only just noticed this topic has replies in it.

 

I've had a few people ask about making props - this does work, but my code is currently very picky about the directions and planes etc needed to get this working.  Sorry I've not had time to cure those problems - dealing with multiple things in arbitrary 3 dimensions is very complicated math!

 

Before you start - make sure you've done all the updates to my add-in (open any menu option of it, and if it asks to update - do that first, then re-start the add-in (shortcut key press "S") and do more updates if there are still more).

 

I've made a screencast and a demo project for you to follow or copy to ensure you can get this working for yourself.  Follow the instructions, or load the demo and change the dimensions to get this to work for you.

 

Ignore the "blade outline" if you see it: that's an as-yet-unfinished option I'm still working on.

 

Here is the demo project: https://a360.co/3N11fuQ

Here is the screencast instructions: https://autode.sk/3vT5u5J

Message 68 of 95
wiebe.baron
in reply to: OceanHydroAU

Hi Chris,

I'm really enjoying using Airfoil Tools, thank you for creating and sharing it.


I 3d printed a 66cm front wing for my wind foiling gear and amazingly (given my skills) was able to foil with it. My sense however is that it is overly cambered to reach the targeted velocity. I had created an earlier draft that appeared thicker and less cambered but had then updated to the latest version of Airfoil Tools, so went back to test this against the Underwater Glider video you had created:

 

Glider Video (v1.20200602 db-81)
Best foil is a tested Re 35,000 n4 and named optbs_spline_Re35000_N4...


v1.20200623 db0

Re 39,858 results from 0.04m chord at 1m/s speed in 20C temp Fresh Water

Best foil is a tested Re 35,000 n4 and named optbs-spline_foil_be6568.dat-s17_n17s0-Re125000-N12.dat. Best L/D=38.343 at Aoa=5.7 lift coefficient: 1.2523, drag coefficient: 0.03266 (friction drag 0.01255 + pressure drag 0.02011)


v1.20220220 db19597
Best Cloud foil is Re 35,000 n4 mach0 and named re2_opt_be5045fvnc2t-M0.05-n17s1-opt_n17s1-opt-Re65536-N6-sq6.dat. Best L/D=37.375 at Aoa=4.6 lift coefficient: 1.2349, drag coefficient: 0.03304 (friction drag 0.01327 + pressure drag 0.01977)

 

Both later versions appear thinner and more cambered:

wings_glider.jpg

The difference is even more pronounced with the full size foil I printed (using the surf hydrofoil preset, 18 degrees temperature, 7mps target):

 

hydofoil.jpg

My sense is that the 2020 foil is the better one, is this a bug or have I messed up somewhere?

 

Cheers!

Wiebe

Message 69 of 95
wiebe.baron
in reply to: OceanHydroAU

I've also been experimenting with small ducted propellers and have some bug reports and questions related to that.

 

The rotation direction seems to be as viewed from the front rather than astern as below:

 

fan_rotation.png

 

The profiles also seem to project slightly beyond the specified blade width (rotation axis/hub nose), both above and below it (as seen above on the hub). Not a big deal but it means some cleanup before it will print.

I also noticed that the vehicle speed cannot be 0 or negative but there seem to be valid use cases for these (hovering / gradual descent)?

 

Small 3d printed props are quite fragile so I've been using the min. thickness option. This doesn't seem to extend along the whole length with small props (1.2mm min thickness):

fan_min_1_2mm.png

Entering realistic parameters is quite critical, here's a 40mm diameter fan at 5000rpm and targeted thrust of 200N, resulting in a negative pitch!  Is there a way of letting users know that targeted thrust levels are not achievable, and indeed what it might be? Also the thrust is presumably based on a single blade, can the number of blades be factored in?

fan_negative_pitch.png

 

With the small blades I've also noticed that the inner profiles are very twisted and fusion is often unable to loft them:

fan_twisted_profile.png

 

Hope this feedback is helpful. Thanks again for creating this great tool!

Message 70 of 95

prop fail 2.PNG

 and im back with another error, when this happens it also softlocks fusion 360 with that error and every time its closed it opens up again

Message 71 of 95
OceanHydroAU
in reply to: wiebe.baron

The most recent update includes a much larger database with more foils and the removal of some old ones that had less than optimal settings matched to them.

One thing to keep in mind is that my optimization target is best lift for least drag at some given set of conditions - for shapes that need to perform well in multiple different conditions, or that have a size that's larger than necessary for the lift they're needing to produce, you'll need to select more of an "average" for what you want so it works better.

I've successfully ported my solver from Linux to Mac and Windows, so my next release is going to give you the ability to generate specific shapes to perform exactly how you need in an arbitrary number of different scenarios (e.g. enough lift to get up at the start, but then as low as possible drag once you're going at speed with just the right amount of lift to keep you up).
Message 72 of 95

Yikes - lockups are not good! Thanks heaps for reporting this - I'll manufacture some deliberate backend failures and get this fixed, but it might take a month (my old Mac can't run latest F360, and new PC is a month away before delivery...)
Message 73 of 95
OceanHydroAU
in reply to: wiebe.baron

Thanks for all these comments! Excellent observation about vehicle speed - extra thanks for that one!
I couldn't figure out programatically where the point is that Fusion360 decides whether or not to loft something - it's very random - I spent ages on that problem before giving up and making my code attempt to carry out the loft again and again using fewer and fewer profiles until it works. This too is a bit hit-and-miss - if often works fine, but then sometimes randomly decides to fail over and over as well.

I've got a fair few new features on the way for props and turbines, including a better blade-outline shape concept, and custom target performance solutions that you can run locally on your own PC to get custom shapes specific for whatever condition tradeoffs you need (e.g. a prop that is efficient at high speeds, but still has enough thrust to launch, etc) - as well as getting rid of the annoying mistakes I've made that force you to select specific planes and directions!

There's also a lot more help I can provide in software to designers based around mass and thrust and blade counts and so forth which I plan to add in.

Profiles extending beyond where you want is a very tricky problem - the nose of a 17-point spline (all shapes use 17pt splines) isn't necessarily at the same place where the leading point is (it's an evil mathematical problem to solve with possibly irrational solutions) so there's not that much I can do there... it's a valid observation though, so maybe I'll see if I can scale & translate the entire output by some tiny calculated amount to get it as exact as possible?
Message 74 of 95
parkpickerl
in reply to: OceanHydroAU

Hi i have been trying to use your propeller feature. Very cool stuff. 

I used your video as a reference. Would you mind making a screen cast where you show us how to create a e duct fan for a model airplane ? A complete one ? 

I am in the middle of kind of blindly tinkering with your tools but the most effective use of your tool is easiest if we can follow your thought process. 

Message 75 of 95
simon.dyer
in reply to: OceanHydroAU

Sending crash report as requested

simondyer_0-1663472246439.png

 

Message 76 of 95
simon.dyer
in reply to: OceanHydroAU

Same issue?

simondyer_0-1663474440532.png

 

Message 77 of 95
simon.dyer
in reply to: OceanHydroAU

Let me know if you dont want anymore bug reports from me.  Im sure Im following instructions but still cant get a foil to generate.

 

simondyer_0-1663534488706.png

 

Message 78 of 95
duesentrieb3
in reply to: OceanHydroAU

Invalid foil data recieved from Cloud service. Reverting to inbuilt DB. Please let us know about this error
Sending screenshot info as requested.

Best regards

Message 79 of 95
kursat.uvez
in reply to: duesentrieb3

I have been getting this same error
"Invalid foil data recieved from Cloud service. Reverting to inbuilt DB. Please let us know about this error" 
for a long time.
@OceanHydroAU Will this be fixed or could it be ignored?
I am about to start building the physical prototype of the project I am working.
If it requires changes I can do  that now. Otherwise, it will be timewise quite costly to fix it later.
thanks

Message 80 of 95
jmshrtn
in reply to: OceanHydroAU

Hi there.

 

Thanks for this awesome tool. I have a question and a bug report:

 

  1. I want to build a long range FPV plane that has it's sweet spot at ~50kph (~13mps - the screenshot is for 20mps because I wanted to see how changing the speed alters the camber - answer; not much) at 120m altitude, now whenever I try and generate a wing airfoil for anything approaching these specs (in this case with a 140mm chord) I keep getting foils with heaps of camber. I was expecting something a little more flat. Am I using the tool incorrectly somehow?
  2. The second screenshot is a crash caused by asking for a constrained clark-y with the dat file downloaded from airfoiltools.com.

 

Thanks again for the awesome tool @OceanHydroAU.

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