Using Surfaces

Attached are couple of guidelines showing how Surface modeling can be used to create typical aircraft geometry that might be difficult to model using the Solids tools. (They are "guidelines" because I'm too lazy to put together complete tutorials!). I wrote them a few years ago, but I think the concepts/techniques shown in them are probably still useful...

Thanks for posting this.

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Originally Posted by SFahrner

Attached are couple of guidelines showing how Surface modeling can be used to create typical aircraft geometry that might be difficult to model using the Solids tools. (They are "guidelines" because I'm too lazy to put together complete tutorials!). I wrote them a few years ago, but I think the concepts/techniques shown in them are probably still useful...

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Will you please post the actual models (with a link here) for your elliptical wing shown in the wing tips document? I was intrigued to see you used a swept boss to form it, with just a root rib and 2 guide curves. Simple! So I tried it out. But I couldn't figure it out even with SWx Help. Or just take a picture of the property manager.

Here's the way I tried to do it. You can see it lost the airfoil as it swept toward the tip. Thanks!
Mark
Attachment 6013

Well, I found the model, but I don't know how to post it to the Forum (my usual tricks of changing the extension or zipping the file don't work!).

If you're still interested, send me a PM with your e-mail, or give me some guidance on the best way to set up a link and I'll be glad to get the model to you (and I promise it won't take another six months!)

Cheers,

SF

Oh, I should have added that one of the ways to control sweeps like this is to have the profile be a single proportional spline. This allows to grow/contract without distorting as it seeps along the guide curves...

Quote:

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Originally Posted by SFahrner

Well, I found the model, but I don't know how to post it to the Forum (my usual tricks of changing the extension or zipping the file don't work!).
If you're still interested, send me a PM with your e-mail, or give me some guidance on the best way to set up a link and I'll be glad to get the model to you (and I promise it won't take another six months!)

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Steve: Could you please post it to GrabCAD, tag it EAA and post a link in this forum? Thanks!

https://grabcad.com/library?page=1&t...cent&query=EAA

Sorry it took so long to post this - I really need to check this Forum more often!

Here is a link to the model:
https://grabcad.com/library/elliptical-wing-1

A couple of comments:

Again, converting the Spline to a "Proportional Spline" in the Spline Property Manager will fix the shape of the spline, but allow it to grow/shrink as it sweeps along the Guide Curves.

Also, I try to avoid sharp corners (i.e, sharp trailing edges) whenever possible. Singularities like that lead to real problems in sweeps and lofts...

SF