Best practice: fuselage + wing

A place to share learning material: written tutorials, videos, etc.
soaring
Posts: 40
Joined: Sat Dec 31, 2016 10:27 pm

Best practice: fuselage + wing

Postby soaring » Mon Dec 31, 2018 3:41 pm

Hello,

i've spent some time in FreeCad for dry/run fuselage/wings with standard workbenchs and some additional python scripts.
i've spent also some time on forum and read than many people did the same, with some results / hack / tools that differs but did the job.

As hobby, i do some RC Gliding and use FreeCad as a day to day basis for 3D printing. I think it is possible to extract some best practices from users experience, tools, scripts, dry/run/fail/retry/success :-) and share them to the community.

It's the reason why i starting a dedicated thread, maybe some articles, new tools, workbench will emerge from it, i hope !

For dealing in the past with nurbs, i feel that curves workbench (addon) can help a lot, as i read it offers gui tools available only through API. Microelly did also a fantastic job on nurbs.

Thread is Open ! i will start with a first image of my personal work :-)

welcomed and hoped contributors :mrgreen: :

Chris_G | https://forum.freecadweb.org/memberlist ... ile&u=2561
Stéphane Combet | https://forum.freecadweb.org/memberlist ... le&u=18468
microelly2 | https://forum.freecadweb.org/memberlist ... ile&u=2364
hammax | https://forum.freecadweb.org/memberlist ... le&u=12483
GlouGlou | https://forum.freecadweb.org/memberlist ... ile&u=5772
saso | https://forum.freecadweb.org/memberlist ... ile&u=3305
...

--------------------------------------------------------------------------------------------------------------------------------------------------------
Github repository for working on some Templates : https://github.com/soaring-community/freecad-pattern
--------------------------------------------------------------------------------------------------------------------------------------------------------
Last edited by soaring on Wed Jan 02, 2019 8:47 am, edited 9 times in total.
soaring
Posts: 40
Joined: Sat Dec 31, 2016 10:27 pm

Re: BEST PRACTICE : FUSELAGE + WING

Postby soaring » Mon Dec 31, 2018 3:44 pm

.
Attachments
fuselage.jpg
fuselage.jpg (99.05 KiB) Viewed 1935 times
soaring
Posts: 40
Joined: Sat Dec 31, 2016 10:27 pm

Re: BEST PRACTICE : FUSELAGE + WING

Postby soaring » Mon Dec 31, 2018 3:49 pm

Last edited by soaring on Mon Feb 25, 2019 1:18 pm, edited 4 times in total.
chrisb
Posts: 18242
Joined: Tue Mar 17, 2015 9:14 am

Re: Best practice: fuselage + wing

Postby chrisb » Tue Jan 01, 2019 4:05 am

I changed the subject capitalization. Using all caps is considered to shout at us.
soaring
Posts: 40
Joined: Sat Dec 31, 2016 10:27 pm

Re: Best practice: fuselage + wing

Postby soaring » Tue Jan 01, 2019 8:01 am

Thanks chrisb, i will pay more attention about rules, don't hesitate to PM me to fix issues if necessary !
User avatar
hammax
Posts: 851
Joined: Thu Jan 19, 2017 5:03 pm
Location: Ammersee

Re: Best practice: fuselage + wing

Postby hammax » Tue Jan 01, 2019 12:30 pm

… the thread title is "Best Practise".
This post is simply "some practise" by an example of experiments with ChrisG's CurvesWB - here Sweep by 2 Rails.
Its only a trial to model a bird's wing. Massive Leading Edge, thin Trailing Edge, no turbulence problems,
because feathers damp them away.
I like seagulls, they are the most elegant allweather flyers.
For comparison to "Sweep by 2 Rails" there is also a loft out of the wing profiles.
The profiles are open to get points for the wires of the ruled surface.
I also experimented with scaled clones of a master profile.
The Pipe profiles are another usable feature for a loft e.g.

Wing_6.PNG
Wing_6.PNG (95.77 KiB) Viewed 1825 times
Wing_5.PNG
Wing_5.PNG (39.84 KiB) Viewed 1825 times
Attachments
GullsWing2.FCStd
FC.18.15521
(100.9 KiB) Downloaded 65 times
soaring
Posts: 40
Joined: Sat Dec 31, 2016 10:27 pm

Re: Best practice: fuselage + wing

Postby soaring » Tue Jan 01, 2019 1:46 pm

Awesome ! this seagull wing contains all concepts for a wing (diedrals, arraow, foil sizing / change), perfect !
My current freecad install is currently broken, when it fixed i gonna give it a try !

Thanks for your work ! this sample is a very good starting point to play with !
soaring
Posts: 40
Joined: Sat Dec 31, 2016 10:27 pm

Re: Best practice: fuselage + wing

Postby soaring » Tue Jan 01, 2019 3:04 pm

So, Freecad is back ! My first observation is regarding the Trailing edge.

with standard Loft/Sweep, we can see some broken / "rasterisation" on the edge, with "sweep by 2 rail method", it's ok.
it was for me a limitation for wing design... good news !
Attachments
trailing edge comparison.jpg
trailing edge comparison.jpg (57.58 KiB) Viewed 1798 times
soaring
Posts: 40
Joined: Sat Dec 31, 2016 10:27 pm

Re: Best practice: fuselage + wing

Postby soaring » Tue Jan 01, 2019 3:28 pm

2nd observation :

before the final design workflow step (approximation), we've got the "sweep 2 rails" step.

Question 1 : what is the color code used for drawing point ? Is there some information regarding color ?

Question 2 : It seems that naturally some foil where design with plots, but there is only 4 "sketches foil "...what is the method behind ?

Question 3 : there are more "plot foils" where the diehdral is important, is it automatic ? Im feeling answer is settings in property panel regarding knots or approximation algorithm, etc...if all is automatic (following an algo / method), it's opening the door to simplify complex approach existing today outside Freecad, in the real world (ex : moving naturally between 2 different foils, creating by the way intermediate foils on the go !

Question 4 : as i understand (but maybe i'm wrong", foil must be opened for "sweep2rails" compute be ok. Is there a simple way to design or transform the result to obtain a solid wing in the final workflow step ? Idea behind is to allow boolean operations. As is, it could be possible to construct ribs by substraction, one of the simplest approach when you have complex/twisted wing, i guess...
Attachments
sweep2rails.jpg
sweep2rails.jpg (37.79 KiB) Viewed 1796 times
User avatar
Chris_G
Posts: 1121
Joined: Tue Dec 31, 2013 4:10 pm
Location: France
Contact:

Re: Best practice: fuselage + wing

Postby Chris_G » Tue Jan 01, 2019 3:58 pm

soaring wrote:
Tue Jan 01, 2019 3:04 pm
So, Freecad is back ! My first observation is regarding the Trailing edge.
with standard Loft/Sweep, we can see some broken / "rasterisation" on the edge, with "sweep by 2 rail method", it's ok.
it was for me a limitation for wing design... good news !
This is only a tesselation pb. It doesn't say much about the quality of the underlying geometry.
The GeomInfo tool (icon is a blue circle with "i" inside) gives a better "feeling" of the quality of a curve or surface
soaring wrote:
Tue Jan 01, 2019 3:28 pm
before the final design workflow step (approximation), we've got the "sweep 2 rails" step.
Question 4 ...
I would recommend to use the Gordon surface method if possible, it is more precise.
I think it is possible to build up watertight models with it, while the "sweep 2 rails" way cannot.
soaring wrote:
Tue Jan 01, 2019 3:28 pm
Question 1 : what is the color code used for drawing point ? Is there some information regarding color ?
There is no color code. They used to be all black with Py2/Qt4, but they get random colors with Py3/Qt5. I don't know why ...