Solidworks Questions Building it Like Vans Does it

[Aluminum]

I'd pitch in $100 to have Van's engineers make a series of step-by-step youtube videos showing how to do a structural and aeroelastic analysis of, say, a simple empennage model. Let's a hundred of us pledge to make it worth someone's while?

In this new normal they could then totally expand into distance learning and grant degrees. Buy-your-own sheet metal to graduate.

[mbauer]

Originally Posted by Snowflake

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.

I see what you're saying. Never considered what the difference would be for a full size aircraft.

My designs are small models made using cardstock paper, 7ft Long SR71 Blackbird is my biggest airplane so far. The angle on the connections is so small that just cutting the rib outline and skinning with cardstock paper makes it look like a continuous curve. Actually when cutting the ribs, they already look like a continuous curve.


@Terry- Thank you for the explanation. Sure sounds like you have a great career!

@Brandon-Thank you for mentioning how you design. Makes perfect sense.

Best regards,

[Luke D]

Originally Posted by 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

Very interesting subject to me, so I couldn't help throwing in my 2 cents. Brandon's approach is very close to mine. I've been using SW since about 2007 in our business designing RV interior components (mostly sheet metal parts). In my spare time I've dabbled with a few aircraft designs over the years. I hope to eventually get one flying.

Anyway, I find that design of any kind is a very iterative process with many changes over time. It's easy to get bogged down with the mechanics of using the software even once you are very proficient.

For me it helps to work with a single part file to work out the complex relationships between multiple related parts. These parts are actually just individual "solids" in the same part file. I think of this file as a very rough concept. Once I like the layout, I basically go back and redesign everything from the ground up in proper part and assembly files. It works great for working through issues in subassemblies.

One other secret weapon when doing machanical design with SW is to make use of the McMaster Carr website (and many others) for solid models of many hardare parts and piece you can download directly. Fun stuff.

[Snowflake]

Originally Posted by Luke D

One other secret weapon when doing machanical design with SW is to make use of the McMaster Carr website (and many others) for solid models of many hardare parts and piece you can download directly. Fun stuff.

Hey now, don't give away *all* the secrets or soon those of us who do this for a living will be out of a job! :P

McMaster is my standard reference for fasteners as well. I've stopped creating part numbers for fasteners, I just use McMaster's numbers and specify them as the default source. If customers want to get fasteners elsewhere, finding the detailed spec for the fastener is easier by going to McMaster with their part number.

[Luke D]

Originally Posted by Snowflake

Hey now, don't give away *all* the secrets or soon those of us who do this for a living will be out of a job! :P

Most of your secrets are safe. I'm just an amateur.

[way_up_north]

Thanks for all the great responses

Ive hit a snag and wondering if anyone of you know of a work around

The issue is the spline tool in the Solidworks sketch

I`m posting here after reading about 10 posts by different posters on Solidworks and CADforums has on this topic


The spline tool seems so useful I’m surprised that there are issues with it being the software is 20 plus years old. I’m new so maybe I just don’t know all the alternatives to add curves to airframe parts... ect
Ive been making practice wing shapes/airframe parts, by making a center line and then drawing lines up and down off that. Then take the spline line tool and connect the dots. Ive been using this method for wing shapes that don't have airfoil coordinates or just for making curves and air frame shapes


But when I put that sketch onto a drawing in Solidworks or export that drawing to a PDF.....the nice curve of the spline line is gone, replaced by a number of short lines(polylines) that approximate the curve....so from far away it looks ok but up close its very blocky

On the solidoworks forums and Cad forums people seem to be stumped by this issue...that the spline tool creates great curves in sketch mode but anytime those curves are exported to do a 3D print or PDF..ect...the curves disappear and blocky lines are put in it place. Some have talked about using arcs to make curved shapes as a work around. Any of you have experience with arcs or other tools to do wing type shapes? I`m new this cad world, can the arc tool be extended like a spline?

This is after adjusting image quality settings and options in how the PDF is saved...etc..looks like almost every stone has been turned looking for an answer to this...

I dont know how to host pictures on this site to show you ...or I would post some examples...

Ive made the exact same sketch in fusion360 and had no issues exporting or printing, but I want to stay with solidworks as its the EAA choice

Maybe youve run into this yourself and have a solution

Michael

below is a post off the solidworks forum of someone posting on the same issue





I am trying to export a drawing to Illustrator so that i still have splines and circles. At some point this must have worked for me, as i have old exported DXF files which have splines in them. But with my current Drawing i cant get it to work, Solid Works will export all the Splines and Curves as edgy polylines! I already tried all the options and different DXF standards, but nothing helps...

Thanks for your advise!

Philip


This is a link to another person same issue

https://forum.solidworks.com/thread/223872

[way_up_north]

Another question for you guys, i`ve watched all sorts of videos on entering ready made airfoils into solid works. But what if you want to enter your own?

If I have measurements from an airfoil , solidworks has a manual entry system to put them in under insert/curves/curves through xyz points

the thing is, I cant find anywhere an explanation on how the numbers should go in. If anyone has done their own airfoil matrix for solidworks from scratch, id love to hear about it.

I have measurements I want to try but every time i put them in I`m creating a modern art image and not an airfoil...lol

Michael

[Snowflake]

Originally Posted by way_up_north

If I have measurements from an airfoil , solidworks has a manual entry system to put them in under insert/curves/curves through xyz points

the thing is, I cant find anywhere an explanation on how the numbers should go in. If anyone has done their own airfoil matrix for solidworks from scratch, id love to hear about it.

I haven't used the xyz points method, but I imagine all you need to do is enter your coordinates for your airfoil in two of the axes, and zeroes in the third axis.

The other way would be to just sketch them and dimension them. Draw a line from the origin straight along one axis to make your chord line, then draw vertical lines from the chord line to each point on the profile. Your airfoil coordinates are then the distance of the vertical lines from the origin, and the height of each vertical line. It's more labour-intensive to draw and dimension this way, but it's equally valid.

[Snowflake]

Originally Posted by way_up_north

But when I put that sketch onto a drawing in Solidworks or export that drawing to a PDF.....the nice curve of the spline line is gone, replaced by a number of short lines(polylines) that approximate the curve....so from far away it looks ok but up close its very blocky

Can confirm i've seen this for years as well, and have never found a solution.

[mbauer]

Originally Posted by Snowflake

Can confirm i've seen this for years as well, and have never found a solution.

Does SW have any Nurbs controls to adjust how they appear?

Non-uniform rational basis spline

Non-uniform rational basis spline (NURBS) is a mathematical model commonly used in computer graphics for generating and representing curves and surfaces. It offers great flexibility and precision for handling both analytic (surfaces defined by common mathematical formulae) and modeled shapes.

Could it possibly be a setting in Illustrator when importing splines/Nurbs?

Whoops-reread posts. PDF is based on bitmap/pixels, not vector, Illustrator is based on vector. When a vector drawing is converted to bitmap, you loose the vector lines, they are converted to single dots to make the line/drawing appear correct. Vector uses geometric shapes to show a line or curve.

Mike