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Need help - creating aircraft wing ribs

I need to cut aircraft wing ribs. How would I go about this in CAD software. I found a pic online that I may be able to size. Easy way to go from .JPG to G-code?

I don’t know of any CAD software that does this. Inkscape can handle it and then export 2d formats like dxf or svg.

Any “vectorize inkscape” or “inkscape bitmap trace” tutorial should get you started. It’s more of an art than a science; depending on the source image you may need to play around with different methods to get a clean drawing.

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inkscape can do it, but I find corel draw does it better with more options, but not cheaply.

Thank you for the information. I just watched “this old Tony” on youtube. He uses fusion 360 for everything.

For an aircraft wing with only an .jpg as input I would use inkscape (linux user) for tracing the picture. Then I would use a program that will allow you to edit the imported .svg (in my case FreeCAD). I would read a little on Giggle about how the lift is created, about whirlpool on the edges and then play with the sketches I have in freecad and correct any import differences in the measurements that result from the previous workflow.

Easel has a Wing Rib app add-in that probably does exactly what you want.


Gero. No edges needed, thankfully I only broke the inboard two ribs on each wing. The snow load on the (make shift) hanger broke through and took two supports with it, hitting on each side of the wing, nearly taking out the cockpit glass. It needs to be accurate though, to slip on the wing support tubes. I may end up rebuilding the wing in which case I will experiment with wing tips at some point but they will be made out of carbon fiber or the like. Thanks for the tip.

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Good to know. I am not sure if Kit-fox uses standard ribs or their own but the internals are proprietary. The manufacturer had a factory fire and can no longer help me. Further more the fit has to be as accurate as possible as not to change the flight characteristics. Although I could just “wing” some measurements.

I think I remember coral draw from the 80’s. It’s been around for a long time, probably really good now.

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If you can get a hold of .dxf files or such, for precision you are better to start from there.

You can generate SVG files from the airfoil plotter on this site.

You could then import and scale it up in your CAD/drawing program. That would get you the outline
to get started, and if you know the NACA number your wing is based on , may get you close to what you need.

There is a Youtube channel called ‘Tech Ingredients’ that used the airfoil tool to design a catamaran hull.

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You want to try this:

You have all given me such cool resources, I may end up manufacturing aircraft one day. For now, it is frustrating. I need to convert the pic of the wing rib so it doesn’t end up looking like a cartoon with varying line thickness etc. On top of that, it needs to have dimensional accuracy. I feel like a small child that wandered into a quantum physics convention.

The height is 5.6" and length is 41.625"
It seems like such a simple thing/simple shape yet cleaning up the pic has proven unsuccessful for me, so far.
My hole saws and jigsaw are staring at me every time I walk into the garage, I am tempted to just trace the outline with a broken rib and use them, even though I got the maslow specifically for this project. I only need to cut 4 or 5 ribs out of 1/4" ply.
Kind of embarrassed that I thought the CNC option wold save time and frustration. I will keep at it for the sake of future projects though.

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My experience with CNC is that it is harder and slower at first, especially if you have to build the CNC before you use it. The learning curve is steep in that there are a lot of things to learn to be efficient at it. Once you have learned how to use it, though, it is often faster and more consistent than conventional methods.

Specific to your problem, I would approach it like this:

  1. Take your image and using Inkscape, define the airfoil contour and the “corners” of the all the interior stuff by fitting circles to them. I went ahead and did this and the result is this .svg file:

Here it is in .png form just to show how the vector forms line up with the image:

  1. Import the svg into CAD or if that doesn’t work, dig into the .svg file to find the coordinates of the circles (.svg is a text-based format). Then use those coordinates in a CAD program to lay out a sketch of the internal parts. Draw the lines that connect the corners and make them tangent to the corner circles. I would do this part in CAD because I don’t know of a way to enforce tangency in Inkscape.

  2. Extrude the sketch into a solid and cut it on a CNC or laser cutter, depending on your material, etc.

I’m sure there are other folks on the forums who would take a different approach, and I’d be interested in hearing theirs.

Hope this helps!

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Oh, the other thing I would do is check the NACA airfoil series to see if the external contour conforms to one of them. You would be amazed how many airfoil shapes are just NACA contours.

Looks like @jwolter posted it before I could, but I traced it. Quick trace in corel draw gave me something that looks like this:

Not super impressed, but if you have inkscape you can use the line editor and straighten it out. here is the svg:
No need to use it if you already have one working.

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Yes! I won! :wink:


Inkscape and freecad, better late then never :grin:


You posted a little later, but you took it farther than I did. Nice work!


Oh yes this helps a lot. Thank you. I could use this approach to make some changes to areas that I intend to modify, like for running a fuel hose or attaching some aluminum bits, instead of drilling holes later.

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