Good day!

Thanks for reading my inquiry. Can anyone please help me out with a suggestion as to how I can create an airfoil shape wing from a cross-section at the base of the wing as profile curve and two guide rails, one for the leading edge of the wing and one for the trailing edge of the wing? I've tried various different approaches, all involving the sweep tool, but it doesn't seem like I'm properly communicating to MOI what I want it to do. Which is to extrude or sweep the cross-sectional profile of the root of the wing perpendicularly to the cross-sectional profile's surface, from the base or root of the wing towards its tip, but scaling it continuously throughout the sweep or extrusion so that the leading and trailing edges of the swept profile remain exactly within the rails defined by the wing's intended leading and trailing edges.

I've attached the .STP if anyone wants to try on the specific model I'm working on. And also this image, which hopefully conveys what I'm trying and failing to do:



Any suggestion or recommendations which you can provide would be greatly appreciated. If this isn't something that can be done with the sweep tool as it is currently implemented, or other MOI tools, hopefully it is something which could be added to some future version of MOI.

Thank you for your time!

Best regards,

Larry.

Hello LarryV,
try to improve your curves, as they have a lot of segments. You need as smooth curve as possible. In this simple design there are sharp leading & trailing edges of your wing, so simple mirroring of upper surface and lower surface can be used. I have used only curves from your model. Sweep command with tangency work quite easily.

Hi Larry,

I hope I've understood what shape you're going for.

I created this solid using a 2 rail sweep. The rails are the green and blue curves (I re-drew them using continuous Freeform curves). The 2 profiles are the red closed curves.

Select the 2 red curves, run Sweep, and select the green & blue as the rails.

Adjust the red oval as needed to get the desired thickness near the wing tip. You can also add more red profile curves if needed to fine tune the taper of the wing.

If you want precise control over the wing taper you can add a Scaling Rail (light blue curve in 3rd image). Same sweep operation as above except first delete the small red profile curve. Sweep as above and click "Pick scaling rail", then Done. History is on, so you can show points on the scaling rail and tweak the taper in real time.

You can also select the same set of curves all at once and Network (last image). Again, select the the light blue "Scaling Rail", turn on "Show Points" and tweak the wing taper . The Network method does not produce a Solid, so after Network, select the large red closed curve and Planar. Then select all the surfaces and Join to make the wing Solid.

If you want more radius on the wing edges then modify the airfoil closed curve ends to be less sharp.

Try all methods.

Ed Ferguson

Thank you both for your input! These are both excellent solutions. I didn't realize that the rails need to be continuous, which they weren't in my model. I was selecting multiple consecutive, disjointed segments and that's why it wasn't working.

I now tried copying the edges of the reference ground plane projection of the wing, deleting that surface, joining the different segments of the leading and trailing edge profile into two individual singular continuous curves and then I was able to use sweep to make the wing shape I wanted.



Thanks a lot, you've helped me out tremendously!

Best regards,

Larry.