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738 Views, 3 Replies

01-29-2013 10:18 AM

Hi

I found tutorial for symmetrical equation curve for NACA Airfouil in Inventor 2013. http://www.youtube.com/watch?v=zKSBe9hImTE

I need to create assymentric airfoil. I am wondering if there is a possibility to put equation in Inventor which looks like the one I attached in doc file.

If it is not possible that's OK as I can use coordinate generator in the internet and put coordinates into inventor so I can draw it but It would be nice to put set of the equations rather than manually put 100 points.

I know that those equations are more complicated and I don't know how to start with them in Inventor

Solved! Go to Solution.

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01-29-2013 11:51 PM in reply to:
PiotrekL1

I'm not in front of Inventor right now, so can't check the syntax for the equation curve editor - but I would say "yes", this is possible. For now, I'd just recommend inserting points from Excel. Inventor will draw a spline through the imported points for you - it's like the poor-mans Equation curve editor! Have a look at the expanded tool-tip for the format of the Excel sheet. (It's on the Sketch > Insert panel.)

Peter

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01-30-2013 12:43 AM in reply to:
pcrawley

Hi

I will follow your advise. I will generate coordinates in the NACA tool and put then through MS Excel into inventor

Thank you very much

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05-13-2013 06:43 PM in reply to:
PiotrekL1

Been working on this to...

My end goal is to have an assembly with n number of NACA 4 digit (and others) profiles. This will allow the user to quickly develop a surface model to export to a CFD program.

Parameters to control (between each section):

- Sweep
- sweep
- dihedral angle
- span
- twist

Parameters to control (For each section):

- NACA Type
- NACA Parameters
- Camber length

**Step 1: Developing NACA 4 digit profiles**

Approach 1: Sketch Equation Curve

Following equitation on http://en.wikipedia.org/wiki/NACA_airfoil, I was successfully able to develop the mean camber line (with two different equation curves). While trying to add the equations for the top and bottom of the profile, I ran into many issues most of which resolved after time, although not all.

Problem(s):

- The parametric equations are not fixed in space (i.e.. you can drag them around) and I have not been able to successfully relate all 6 curves, trailing edge, and leading edge (approx. as a circle).
- The beginning of the forward curves approach div by zero and are as such not useful.
- Very cumbersome, extremely hard to use and error prone.

Approach 2: Thickness Circles + mean camber line = Spline (kinda)

Using my sucsessful mean camber line, I added 10 circles along the mean camber line and demendsioned their linear poisiton along the mean cambber line using the x_u parametric equations, and their heigth demension from the x-axis using the y_u parametric equations.

Problem(s):

- After passing the max mean camber position, things started going badly. It turns out that inventor was not parsing the equations correctly. This could be a program or user error, the jury is out on that one. See post here: http://forums.autodesk.com/t5/Autodesk-Inventor/De
mension-Copy-Parse-Error/m-p/3920847 - Cumbersome (seeing a trend here). While I could type all the equation in the tiny window and get it work corretly, I feel I have better things to do in my life, and there is probably a better approach.

Propossed Approach 1: iRule/iLogic/API

The title is garbled because I don't know enough about each of those, but my preliminary research shows this may be the correct approach. The plan is to create a set of point using the parametric equations to define a spline.

If anyone has any questions/comments/advise please let me know.

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