10 Replies Latest reply on Jan 21, 2011 1:34 PM by Rick McWilliams

    Airfoil profile

    reeshi pradhan

      Hi,

       

      I'm trying to create airfoil on the plane ohther than Front, Right, Top. The plane could be at angle to these standard plane. I've coordinate file for airfoil profile.

       

       

      Reeshi

        • Re: Airfoil profile
          Roland Schwarz

          Is the coordinate file in 2D or 3D coordinates?

           

          If the data is in 2D, import the points into a sketch, make a block, then insert the block into the 2D sketch on your desired plane.

           

          There may be a macro out there that can do the needed transform, but I am not aware of one.

            • Re: Airfoil profile
              reeshi pradhan

              Hi Roland,

               

               

              Coordanate file is 2D. How do I import points in Sketch? I don't see any command.

               

               

               

              Reeshi

                • Re: Airfoil profile
                  Dale Dunn

                  Insert, Curve, Curve Through Reference Points for a 2D curve.


                  Insert, Curve, Curve Through XYZ Points for a 3D curve.

                   

                  Look in the help to see what format the curve file needs to be.

                    • Re: Airfoil profile
                      reeshi pradhan

                      Hi,

                       

                      Sorry option is not activated ...

                      Insert, Curve, Curve Through Reference Points .

                      and there is not option to browse the curve file

                        • Re: Airfoil profile
                          Mark Kaiser
                          While not in a sketch, go to insert>curve>curve through xyz points.  Browse for file should now be active.  Your file will need to be a .txt file, with three columns, for x, y, and z.  I assume you'll have "0" values for all of your z values, since it is a 2D only curve.  This should import your points into the dialog box, and you can hit OK to accept your curve.
                          • Re: Airfoil profile
                            Dale Dunn

                            I was also wrong about Curve through reference points being limited to 2D. Sorry, I have not used these in a long time. Curve through XYZ allows you to browse for a data file, either *.sldcrv or *.txt. The help says they have the same formatting, so you can create a simple curve by manually entering numbers, save it to a file, and then examine that text file to see how your data points need to be formatted.

                             

                            Once you have made the curve, it will be a curve object, not a sketch. Create a sketch and use convert entities to get your profile into a sketch. Add some geometry to help with alignment later. Maybe a chord line and center of lift point. Close that sketch and create derived sketches on the planes where you want the airfoil.

                             

                            I hope that sets you in the right direction.

                              • Re: Airfoil profile
                                Daniel Herzberg

                                Also, here's something I learned the hard way: If you get your data from a NACA file, the first and last points (usually on the trailing edge) will not connect.  You'll need to manually extend your lines when you convert the curve into a sketch entity, before creating a block.  Also, make sure the cord length of your sketch is 1 meter (or 1 foot), so when you insert and scale your block, it's easy to create the size you want.  Also, I reccomend saving your block to a new 'Airfoil' folder in the library, so it's easy to reuse.

                          • Re: Airfoil profile
                            Roland Schwarz

                            Somewhere out there someone once had a macro to bring in sketch points from coordinates.  Maybe it was Matt Lombard maybe?

                             

                            Be cautious with SolidWorks splines and curves-from-points.  2D splines have polynomial degrees of x^2 and y^2, which probably doesn't quite match the formula used to generate your airfoil points.  There will be errors in the interpolation between points.

                             

                            You might also wish to experiment with equation-driven curves.

                              • Re: Airfoil profile
                                Harold Brunt

                                "There will be errors in the interpolation between points." That will the case for any bspline surface no matter how it is generated.

                                 

                                I thought I had downloaded something from Mahir a couple years ago but I can't seem to find it. Perhaps I am mistaken. I did find a spread sheet that will fit a spline to a series of X-Y coordinates though. I have not had the chance to try it but the contact info is on the third page if you have problems.

                          • Re: Airfoil profile
                            Rick McWilliams

                            Insert curve will get the data points into solidworks. The spline that solidworks creates has some poor aerodynamic qualities. Overlay a sketch and convert entities. Activate curvature combs and you will see the irregular rate of change of curvature.  Create a new airfoil shape with a circular leading edge, and a squared off trailing edge, draw a new spline with only a few control points snapped to the original data. Adjust the upper and lower surface splines watching cruvature combs. Remove constraints and convert to proportional curves.  Redo the constraints at leading edge circle and trailinge edge line. The trailing edge should have a thickness that relates to the boundary layer thickness and construction limitations. A minimum of 0.005 c. You can then make a sketch block and paste it onto any plane. I expect that it will then need to be exploded for a proper sweep. Beware of lofts as they can distort the shape. Add some extra guide curves to keep this under control. Look at curvature combs to check for nasty distortions.