Solidworks Questions Building it Like Vans Does it

[way_up_north]

Hi everyone...

I was so impressed when I was building my RV-7 with Vans match hole acuracy, its inspired me to take a look at Cad software

I`m learning Solidworks and having fun. I`m practicing making structures and assemblies and thought why not try to make a wing or structure like Vans would

questions:

do they make the ribs in the sheet metal feature or do they make a solid rib shape extruded and shell it?

for match hole construction/rivets. i`m not that far into the software to consider but some pointers would be great so i`m learning the subjects leading to that

any pointers from Solidwork gurus would be great...

Michael

[flion]

Solidworks is fun, isn't it? You'd have to ask Vans to be sure, but I'd assume they use the sheet metal feature for sheet metal parts with the material set appropriately to preserve bend radius and match the CNC tooling. Other parts, such as the cowling, would be a shell or, like weldments or thick parts such as spar strips, drawn in simple form.

I haven't played around with hole-matching but I suspect you could use assembled parts to match holes. For instance, build a rib with holes, assemble it at stations to a spar and wing skin, then locate holes in those parts to match. This thread has some suggestions.

[jcarne]

I work with SolidWorks quite a bit. I would bet they use the sheet metal tool for most of the airframe and the cowl/tips/ most fiberglass stuff is probably done with surfacing commands. Surfacing commands is an area I could get better with but they are significantly harder to use.

[Snowflake]

Keep in mind that the airfoil shape isn't comprised of flat segments, it's a continuous curve. So you'll have to reconcile making flat tabs sit against a curved skin at some point.

Think in terms of how the parts are actually made... The shape is cut out of a flat piece of aluminum, and then it is formed over a die to make the rib (if you look at the leading edge, the tabs aren't flat, they are curved to match the wing skin.

Solidworks has a Deform tool that will let you push one piece into another... Perhaps this will give you some ideas?

[mbauer]

Originally Posted by Snowflake

Keep in mind that the airfoil shape isn't comprised of flat segments, it's a continuous curve.

I've plotted several airfoils. Use straight lines to do them. This is done using AutoCAD in a 2D drawing.




Best regards,
Mike Bauer

[terrye]

I think the method depends on which release of Solidworks you are using. Older versions in sheet metal didn't allow unbending of a curved flange, only a straight one, so do some experiments to see if you can unbend a curved flange.

To comment on Mike's last post, when I do an airfoil in Solidworks (mine are castings for marine propulsion) I use a spline through coordinate points. These solid models work great with my patternmaker.

[mbauer]

Originally Posted by terrye

I think the method depends on which release of Solidworks you are using. Older versions in sheet metal didn't allow unbending of a curved flange, only a straight one, so do some experiments to see if you can unbend a curved flange.

To comment on Mike's last post, when I do an airfoil in Solidworks (mine are castings for marine propulsion) I use a spline through coordinate points. These solid models work great with my patternmaker.

Have Inventor 2019, just learning how to do the Feature Base Modeling in it. Mastering Sheet Metal Design with Inventor is my go to book for instruction.

Most of my CAD work has been Civil Engineering. Hobby is designing model rockets/airplanes.

Up till now been doing the designing in 2D.

After doing the math for the particular airfoil, baselines are drawn, then I just use offsets to make my "coordinates".

Guessing you use more software to create your coordinates, or does Solidworks plot them for you? (patternmaker?)

I have drawn the airfoils with the spline command, making changes if needed became an issue. (ACAD R14)

Best regards,
Mike Bauer

[Snowflake]

Originally Posted by mbauer

I've plotted several airfoils. Use straight lines to do them.

Yes, as do I. But when you actually build it, do you crease the skin at the end of each straight line segment, or do you "fit the curve" with the skin and have a continuous curve? You model the continuous curve in Solidworks.

[Deuelly]

I've done a couple aircraft in Solidworks. It's really hard to design an aircraft piece by piece without having an idea of the finished layout.

I like to draw the whole aircraft as a solid. Get the look, layout, and positioning down. This gives me the mold lines for all the bulkheads, ribs, and other parts. Then I decide the layout of the ribs and bulkheads and start slicing the solid model to get the mold lines for each sheet metal part. Doing it this way allows me to change the shape of the solid model and the parts made off of it get automatically changed.

Brandon

[terrye]

Originally Posted by mbauer

Guessing you use more software to create your coordinates, or does Solidworks plot them for you? (patternmaker?)

Best regards,
Mike Bauer

I generally start with a set of coordinates from an airfoil book. Then use Excel to scale these coordinates to the chord and thickness I need. Then plot these coordinates in Solidworks as points in a 2D sketch. Join the points with a spline then extrude to the length required. You can do this with different sections, say root and tip, as long as the number of spline points (coordinate points) are the same for each section. In this case you would use a sweep or a loft. Sometimes guide curves between sections are required to keep the solid from twisting between sections.

Once I have a solid model, I send this to our patternmaker who has a 3/5 axis gantry CNC milling machine. They scale the solid model to allow for cooling shrinkage depending on the actual casting material. The pattern is made of wood. The foundry then uses this pattern to make a mold to make the casting.

This is one of the things I love most about using 3D CAD - the CAD/CAM connection. Most gratifying to see your solid model turned into an actual part.