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Wrap Feature for Airplane Fuselage

Question asked by Brandon McCool on Dec 3, 2015
Latest reply on Dec 26, 2015 by Brandon McCool

I am part of a RC airplane club at school and this year we have decided to try a different route with designing our plane. Instead of having many different components that are glued in place for the fuselage structure, we are exploring the possibility of laser cutting plywood sheets to spec, for the sides. This simplifies the construction phase and allows the shape of the fuselage to conform the the shape of a symmetric airfoil (as opposed to having a very boxy truss structure), which helps reduce drag on the airframe. I have attached my efforts of what I described above.

 

The curve is imported data points from an airfoil database and is what we hope to shape the sides of our fuselage around. In order to have the plywood laser cut, it needs to be flat. Once cut it would be glued into place with formers (vertical members that maintain shape and strength) spaced along the inside to maintain this contour. So we need to somehow flatten the curve in SolidWorks instead of just converting entities onto a plane and laser cutting that.

 

In my research of ways to do this and own attempts, I came across Surface Flatten, Sheet Metal Flatten, Sheet Metal Swept Flange, and Wrap.

 

Surface Flatten doesn't allow a surface to be flattened if it has holes cut out (which is necessary to reduce weight). We can't cut these holes after flattening the surface because it's too much guess work and the fuselage design is fairly iterative as it is. Apparently SW will be implementing this capability in 2016.

Sheet Metal doesn't work with user input curves (that I have seen) - only with arcs and flat faces.

I have been experimental extensively with this Wrap feature. The attached file is where I am right now. Since there is curvature to the side of the fuselage, the direction normal to that surface is always changing, so these cutouts cannot be extrude cut. I projected the desired (at this point in time they are arbitrary) cutout sketches onto the curved face and then made surfaces out of them. Then thickened cut them (this is to remedy the fact that the direction normal is always changing). Now that I have these correctly cut cutouts, I tried to use the Wrap function to deboss onto the surface that is flattened (FYI Sketch27 is what is on the surface-flatten). If this worked, then we'd have the exact face that we could laser cut and it would make things so much easier later on - also one hell of a good looking fuselage.

 

If anyone has an idea worth exploring, I am open to anything. I have been trying to figure this out for almost 10 hours now across two days. If you open the file, and try to use Wrap yourself, you will notice that something funky is going on towards the front ,where the surface flatten is tangent to the fuselage curve. I don't think there is any interference, but the very first cutout shows the yellow line shooting down. I'm not sure what this is about, maybe bad geometry, but it could be a reason why the Wrap doesn't work. I get the error:

 

"Wrap failed, could not use any contour(s) from sketch."

 

I have determined that this is possible going the other way around, that is by debossing a sketch from the flattened surface onto the curve of the fuselage. But like I mentioned before, this would be guessing at where the cutouts would land when they are wrapped onto the side of the fuselage.

 

Again, we would greatly appreciate any input. Thank you very much.

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