Empathy List Archives

B

Benjamin

Sun, Jan 29, 2017 9:26 PM

Hi,

I set up a page that displays the UIUC
http://m-selig.ae.illinois.edu/ads/coord_database.html Airfoil
Coordinates Database:
http://chaaawa.com/airfoils/

and exports to OpenSCAD the selected profile (link to the original .dat
file on the name and in the output):

The points have x between 0 and 1.
To avoid polygon simplification the coordinates are multiply by 1000
then the polygon is scale down.

At least one other tool might follow.
In order to morph a profile with an horizontally mirrored version of
itself, I need to redistribute the points with an external script (to
avoid a pinch in the middle). I should find the time to adapt my first
version and make it available in the output.

Maybe an OpenSCAD solution has already been posted here, I missed it.

Benjamin

Hi, I set up a page that displays the UIUC <http://m-selig.ae.illinois.edu/ads/coord_database.html> Airfoil Coordinates Database: http://chaaawa.com/airfoils/ and exports to OpenSCAD the selected profile (link to the original .dat file on the name and in the output): The points have x between 0 and 1. To avoid polygon simplification the coordinates are multiply by 1000 then the polygon is scale down. At least one other tool might follow. In order to morph a profile with an horizontally mirrored version of itself, I need to redistribute the points with an external script (to avoid a pinch in the middle). I should find the time to adapt my first version and make it available in the output. Maybe an OpenSCAD solution has already been posted here, I missed it. Benjamin

MS

Mark Schafer

Mon, Jan 30, 2017 5:21 AM

very nice.

There are a pile of naca airfoils out there too.
I love these shapes

On 1/30/2017 10:26 AM, Benjamin wrote:

Hi,

I set up a page that displays the UIUC Airfoil Coordinates Database:
http://chaaawa.com/airfoils/

and exports to OpenSCAD the selected profile (link to the original .dat file on the name and in the output):

The points have x between 0 and 1.
To avoid polygon simplification the coordinates are multiply by 1000 then the polygon is scale down.

At least one other tool might follow.
In order to morph a profile with an horizontally mirrored version of itself, I need to redistribute the points with an external script (to avoid a pinch in the middle). I should find the time to adapt my first version and make it available in the output.

Maybe an OpenSCAD solution has already been posted here, I missed it.

Benjamin
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MichaelAtOz

Mon, Jan 30, 2017 12:10 PM

If you reply to this, please delete the previous email, or don't quote it. It
is large and triggers mailing list size protections.

Admin - PM me if you need anything, or if I've done something stupid...

Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above.

The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ time is running out!

View this message in context: http://forum.openscad.org/UIUC-Airfoil-Coordinates-Database-tp20264p20271.html
Sent from the OpenSCAD mailing list archive at Nabble.com.

If you reply to this, please delete the previous email, or don't quote it. It is large and triggers mailing list size protections. ----- Admin - PM me if you need anything, or if I've done something stupid... Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above. The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ time is running out! -- View this message in context: http://forum.openscad.org/UIUC-Airfoil-Coordinates-Database-tp20264p20271.html Sent from the OpenSCAD mailing list archive at Nabble.com.

HL

Hans L

Mon, Jan 30, 2017 5:35 PM

Neat page. I am fascinated by aerodynamics and airfoils, and I'd like to
eventually design some impellers using OpenSCAD. I'm trying to teach
myself about these topics but haven't made a lot of progress yet.

Just curious if you have any information or references about how you
evaluate these various airfoils for use. How do you choose the right shape
for your application? Do you use any specific CFD modeling programs?

Thanks,
Hans

Neat page. I am fascinated by aerodynamics and airfoils, and I'd like to eventually design some impellers using OpenSCAD. I'm trying to teach myself about these topics but haven't made a lot of progress yet. Just curious if you have any information or references about how you evaluate these various airfoils for use. How do you choose the right shape for your application? Do you use any specific CFD modeling programs? Thanks, Hans

B

Benjamin

Mon, Jan 30, 2017 11:21 PM

Just curious if you have any information or references about how you
evaluate these various airfoils for use. How do you choose the right
shape for your application? Do you use any specific CFD modeling
programs?

The blower for the foundry was built after reading:
An optimal design algorithm for centrifugal fans: Theoretical and
experimental studies
Cheng-Hung Huang and Min-Hsiang Hung
Department of Systems and Naval Mechatronic Engineering, National Cheng
Kung University, Tainan, Taiwan, R.O.C.
pdf http://chaaawa.com/airfoils/pdf/centrifugal_fans.pdf

Not the number of blades, but their profile NACA 6412 and orientation.
(… and written before Ronaldo's fillet function, as seen at the junction
of the blades and the base)

With a DC motor from an inkjet printer it melts aluminium (with homemade
charcoal http://www.instructables.com/id/Dirt-Cheap-Charcoal/)

but probably would do the same with flat rectangular blades, like Vik
Olliver did before http://www.thingiverse.com/thing:7350.

For my toy propeller
http://forum.openscad.org/Sweep-with-easing-equations-td20075.html#a20083,
I choose a profile thick enough* to be printed nicely on both edge, NACA
8424. Those toys are also known to fly with flat blades, but it's easier
for children with an airfoil (tested, and not only with mine). The shape
makes the toy accessible to younger people, and is more pleasant.

I want to make wind turbines, there are lot of profiles in the UIUC
dedicated to that :
http://chaaawa.com/airfoils/wind.html

Sweep, morph, skin are fantastic additions to OpenSCAD.
Make sure to have the required files in your library to run the demos:
https://github.com/openscad/list-comprehension-demos

I'm thinking about a graphical assistant to draw the path transform with
bezier curves and background image. I have a beginning of a polygon
editor like Daid's one, with zoom, pan, multi points selection and
manipulation, for something different and for tablet (polyhedron written
to the server). screenshots 1
http://chaaawa.com/airfoils/img/coquille_selection.png, 2
http://chaaawa.com/airfoils/img/coquille_slices.png.
(I also need a curve to modify the rotation along the extrusion, that
will mimic Lightwave's envelopes).

But everything is already possible without assistant.

I don't use CFD modeling programs. With my sons we spent one hour or two
looking for online analysis tool to feed the profiles into, but we
didn't find anything convincing.

(*) That's the reason why I wanted to sort the 1550 profiles by area, to
browse the thick ones in the last pages.

Benjamin
Now aware of the 200k limit, sorry.

> Just curious if you have any information or references about how you > evaluate these various airfoils for use. How do you choose the right > shape for your application? Do you use any specific CFD modeling > programs? > The blower for the foundry was built after reading: An optimal design algorithm for centrifugal fans: Theoretical and experimental studies Cheng-Hung Huang and Min-Hsiang Hung Department of Systems and Naval Mechatronic Engineering, National Cheng Kung University, Tainan, Taiwan, R.O.C. pdf <http://chaaawa.com/airfoils/pdf/centrifugal_fans.pdf> Not the number of blades, but their profile NACA 6412 and orientation. (… and written before Ronaldo's fillet function, as seen at the junction of the blades and the base) With a DC motor from an inkjet printer it melts aluminium (with homemade charcoal <http://www.instructables.com/id/Dirt-Cheap-Charcoal/>) but probably would do the same with flat rectangular blades, like Vik Olliver did before <http://www.thingiverse.com/thing:7350>. For my toy propeller <http://forum.openscad.org/Sweep-with-easing-equations-td20075.html#a20083>, I choose a profile thick enough* to be printed nicely on both edge, NACA 8424. Those toys are also known to fly with flat blades, but it's easier for children with an airfoil (tested, and not only with mine). The shape makes the toy accessible to younger people, and is more pleasant. I want to make wind turbines, there are lot of profiles in the UIUC dedicated to that : http://chaaawa.com/airfoils/wind.html Sweep, morph, skin are fantastic additions to OpenSCAD. Make sure to have the required files in your library to run the demos: https://github.com/openscad/list-comprehension-demos I'm thinking about a graphical assistant to draw the path transform with bezier curves and background image. I have a beginning of a polygon editor like Daid's one, with zoom, pan, multi points selection and manipulation, for something different and for tablet (polyhedron written to the server). screenshots 1 <http://chaaawa.com/airfoils/img/coquille_selection.png>, 2 <http://chaaawa.com/airfoils/img/coquille_slices.png>. (I also need a curve to modify the rotation along the extrusion, that will mimic Lightwave's envelopes). But everything is already possible without assistant. I don't use CFD modeling programs. With my sons we spent one hour or two looking for online analysis tool to feed the profiles into, but we didn't find anything convincing. (*) That's the reason why I wanted to sort the 1550 profiles by area, to browse the thick ones in the last pages. Benjamin Now aware of the 200k limit, sorry.

discuss@lists.openscad.org

UIUC Airfoil Coordinates Database

The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ time is running out!