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Old Jan 12, 2009, 10:34 PM
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Solidworks airfoils to wing generation???

Hi,

I'm struggling to make a wing with Solidworks 2007 SP0. I used to be a reasonable Pro/E driver 10 years ago, but I am pretty new to Solidworks. I have been through most of the tutorials, and have made a bunch of parts and assemblies without too many issues. But I cannot figure out how to make a wing.

I see there are some experienced Solidworks users here that have provided help before, but I can't see a detailed enough answer to get me through this.

I have got as far as getting an airfoil in using the Curve XYZ function through a text file. But it is nailed at the origin - well, offsets wouldn't be too hard in Excel - but it seems very awkward. And once the curve is in, I can't seem to do anything with it. I can't make bring it into a sketch, or extrude it, or anything else that might make it useful.

I can potentially see how I could loft between two airfoils, and even make curved leading and trailing edges using guide curves. If I could use the airfoils.

Is there any other way to bring airfoils in other than the Insert, Curve, Curve through XYZ Points? If not, how do I bring it into a sketch, or do something with it? How could I put twist in a wing if it will only bring in a curve related to the original datums?

I would like to be able to bring in an airfoil through a text file or something, onto a plane I create, hopefully with whatever twist or offsets I need, rather than trying to doctor the offsets and twist in Excel. I understand exporting DXF out of Profili, and then importing it to SW doesn't work that well either.

I hope I don't test your patience too much. Thanks in advance!

Kevin

Edit: I finally found the only command available with the curve selected, so I managed to bring the airfoil into a sketch. So now I can extrude it, or loft between two with an offset built into the Excel XYZ ordinates. The airfoil does not look great when zoomed in, and I'm still not sure how to do washout without a lot of Excel math on the ordinates?
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Old Jan 13, 2009, 11:58 AM
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Phoenix, AZ
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I've been building a few wings using Solidworks and understand your learning difficulties. I'm using Solidworks 2009 and, unfortunately SW is not backword compatible or otherwise I would send you a file. If you have airfoil data in Excel, then the best way to get it into SW is using Curve through XYZ points, as you've already learned. After the curve is in SW, create another sketch on a plane parallel to the curve sketch. Select the curve and "convert entities". That will bring the curve into the new sketch. From there you can manipulate the curve to add twist for washout, etc.

I'm unsure of how manipulating the curve this way affects the accuracy of the airfoil so I try to get the curve positioned as accurately as I can by offsetting in Excel before creating a TXT data file to import into SW.

Once you get the airfoil curves into sketches then a loft using guide curves is the way to make the wing surfaces. I suggest using the surfaces instead of solids in SW as it gives you much better control. They added boundry boss/base is SW2009 which is a big improvement. Previously, boundry features were only available as surfacing tools.

Hope this helps some...
--Colin--
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Old Jan 13, 2009, 12:14 PM
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Thanks Colin! Once I found the "Convert entities" thing, I've been making some progress.

I will try using the surface features, rather than the solid for the wing - it seems to be ignoring a lot of the airfoil points using an extrusion.

I don't know if it is just me, but this seems much harder than it should be!

Thanks,

Kevin
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Old Jan 13, 2009, 12:55 PM
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Yes, it can be difficult at times and certainly tests my patience. I'm not sure what you mean about "ignoring a lot of the airfoil points using an extrusion". If you "extrude" a sketch, only one cross section (airfoil) it will used and it will be a straight feature along an axis. An extrusion is straight by definition, therefore is only suitable for constant cord wings - but you can add "draft" to provide a taper.

If your wing is made up of several different airfoils and is tapering at the leading/trailing edges, then you cannot use "extrude". The "loft" feature is used to connect multiple cross sections. The "sweep" feature is used where you have a single cross section that can be propagated along a path that doesn't have to be straight.

These types of features: extrude, loft and sweep exist as either a solid feature OR a surface feature. Surfacing is very powerful, but much more complex that working with solids. If your wing design is simple, I'd stick with solids if you can get what you want. When the designs get complex, you often need to use a combination of solids and surfaces. Solidworks is known as a hybrid modeling tool for this reason.

If you want, you can send me a file you are having problems with and I can look it over and give you some suggestions.

Rgds,
--Colin--
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Old Jan 13, 2009, 02:37 PM
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Thanks Colin. I may take you up on looking at one of my files if I continue to have problems.

What I meant when I said SW seems to be ignoring a lot of the airfoil points, is, when I zoom in on the wing ends (root, tip), there are large straight lines on the contour. These straight lines are over distances where I know there are multiple airfoil points. I can vaguely see facets on the wing extrusion coresponding with these straight lines on the airfoil.

This isn't a huge issue for me right now, and perhaps surfaces will be better. I just extruded constant chord wing with an AG airfoil file to try it out, and try assembling a multiple panel wing. This could just be a display issue as well.

I will be getting to lofts with multiple airfoils shortly, but I am busy building a shop, and a CNC foam cutter as well.

Thanks again for your help. A few hints can save a lot of menu clicking, Help and internet searching, and general head scratching!

Kevin
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Old Jan 30, 2010, 10:20 AM
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Hi,

did you ever work this out.

When I zoom into my wing tips I see a number of large polygon segments, rather than my clean airfoil that has 100 points on the top and 100 on the bottom.

I "think" it's just a rendering issue, but I may be doing something wrong.

I have a wing with about 5 span stations, but it's only the small stuff near the wing tip that is giving me problems. Tip chord is 37mm & 10% max thickness.

thanks

Matt

Quote:
Originally Posted by kcaldwel View Post
Thanks Colin. I may take you up on looking at one of my files if I continue to have problems.

What I meant when I said SW seems to be ignoring a lot of the airfoil points, is, when I zoom in on the wing ends (root, tip), there are large straight lines on the contour. These straight lines are over distances where I know there are multiple airfoil points. I can vaguely see facets on the wing extrusion coresponding with these straight lines on the airfoil.

This isn't a huge issue for me right now, and perhaps surfaces will be better. I just extruded constant chord wing with an AG airfoil file to try it out, and try assembling a multiple panel wing. This could just be a display issue as well.

I will be getting to lofts with multiple airfoils shortly, but I am busy building a shop, and a CNC foam cutter as well.

Thanks again for your help. A few hints can save a lot of menu clicking, Help and internet searching, and general head scratching!

Kevin
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Old Jan 31, 2010, 10:26 AM
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If you have a spline drawn, then it's just a rendering issue. Go to Document Options, Image Quality to change the display accuracy. Things could get slow if you set the image quality high, depending on your PC.

Greg
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Old Jan 31, 2010, 05:40 PM
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Thanks,

Upped the display accuracy and it fixed things.... But it IS much slower.

Matt

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Originally Posted by gkamysz View Post
If you have a spline drawn, then it's just a rendering issue. Go to Document Options, Image Quality to change the display accuracy. Things could get slow if you set the image quality high, depending on your PC.

Greg
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Old Jan 31, 2010, 06:18 PM
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Kevin, do you know there's a dedicated CAD/CAM forum on RCG? http://www.rcgroups.com/cad-cam-660/

You'll probably get more help there, and it would be the right place for this thread anyway.
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Old Jan 31, 2010, 06:21 PM
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I haven't posted in this thread for a year, and there wasn't a CAD/CAM forum then, but thanks for the suggestion...

Kevin
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Old Jan 31, 2010, 11:59 PM
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Keep in mind that unless you want to see those details in the model on the screen you don't need to run with the display accuracy set very high. Maybe just when you're working on the tip. I know that sometimes it's hard to select a curve exactly when you want to because the displayed curve isn't where the real curve is, when you run into the display accuracy setting limitation.

Greg
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