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What tools do you use for design work?

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lochieferrier

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May 10, 2016
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Cambridge, MA
Hi everyone,

I'm a new member, been lurking for a while so let me know if I'm breaking any posting rules.

It looks like a lot of people on this forum are doing designs from scratch. I've been working on some homebuilt designs and I've got some questions about the processes you guys use to work through a new idea:
  • What software (if any) do you normally use to sketch out new ideas? OpenVSP? Spreadsheets? Custom code?
  • If you want to look at how changing one parameter such as wing area affects an outcome like total weight, how do you do that? Does anyone have ways of automating that process?
  • Is there any sort of standard system for sharing aircraft designs?

I feel like there's got to be a better way to do design than the mess of tools (OpenVSP + Spreadsheets + CFD) that I currently use. Would appreciate any advice or suggestions.

Thanks,

Lochie
 

Mad MAC

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Dec 9, 2004
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I tend to use lots of different tools depending on what problem needs to be solved.

A3 graph paper works well for roughing out ideas & shapes, when it looks right you can scale off it and put it into CAD. CAD can suck time like nothing on earth (& is even worse when you spend more time fighting the CAD system than developing the concept).

Autocad works well for developing 2d mechanisms (copy, paste, adjust design, repeat).

Excel for calculations, with lots of VB.
 

mcrae0104

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Oct 27, 2009
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1. Roll of trace paper

2. Flair pen

3. Calculator

4. AutoCAD (slightly advanced version of #1 & #2)

5. Excel (slightly advanced version of #3)

I'm not doing any 3D modeling or CFD. If I didn't find AutoCAD to be a quick way to record (and later modify) ideas then I would just draw on paper.
 

wsimpso1

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paper and pencil, grid paper, and a lot of excel files, even for analysis of my composite wing structure and landing gear legs.
 

Matt G.

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Nov 16, 2011
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Paper and pencil, calculator, Excel spreadsheets, SolidWorks (free with your EAA membership). I'm planning on using OpenVSP as a sanity check for my hand-calculated (in Excel) stability derivatives.

CFD, in my opinion, is a complete waste of time unless you have years of professional training and experience, particularly if you aren't independently verifying the results with some other method. Same for finite element analysis.
 

Topaz

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...
  • What software (if any) do you normally use to sketch out new ideas? OpenVSP? Spreadsheets? Custom code?
  • If you want to look at how changing one parameter such as wing area affects an outcome like total weight, how do you do that? Does anyone have ways of automating that process?
  • Is there any sort of standard system for sharing aircraft designs?
1) Depends on what you mean by "sketch out". For actual idea-sketching, good old paper and pencil. I've been trying to move over to sketching on my Nexus 7 tablet with a fine-point stylus, but 40 years of paper and pencil is a hard habit to break! Once I get into the more-formal line-drawing stage, I have been using Adobe Illustrator. Not because it's a superior program for that use, but rather because I'm a graphic artist by vocation and it's the drawing program with which I'm by far the most familiar. When the time comes, I'll be lofting my design using a (very) old version of Peter Garrison's Loftsman software. Still runs in Windows 10, and it does the job.

2) I use Excel spreadsheets (or Google Sheets, depending on the situation) for all my calculations. Setting up a spreadsheet to be as parametric as you describe is a challenge. Generally I make spreadsheets in smaller, more-focused, task groups. The way I design (see links in my signature line below), I don't do very many "trial and error" scenarios. The design process I used tends to derive things like wing areas from the design requirements and specifications for the project, so my spreadsheets tend not to be all-encompassing. As for method of seeing how a change in requirements or other design parameters changes the design gross weight, etc., the "sizing" method described in Daniel Raymer or Jan Roskam's books is the basic root for industry methods to do that, and is entirely applicable to homebuilt designs as well.

Aside from XFoil used for airfoil analysis, I don't use any CFD software at all.

3) The only "standard" system for sharing that I know is the plain old-fashioned drawing, even if it's now most-often a digital image: JPEG, PDF, etc. The professional aerospace industry has moved on to exchanging solid models for sharing parts and assemblies.
 

lr27

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Nov 3, 2007
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sharing designs:
In my experience in mechanical engineering, I've seen IGES used a lot. (That's a 3d file that many CAD systems can use.) DXF for 2D. Aerospace may be otherwise, I've never worked in it. In general, most vendors I've worked with can deal with IGES.

I haven't completed an aircraft design, though I have had two projects that resulted in many scribbles and the death of many trees. I think it may have been my wife's idea, but I've sometimes thought of making and selling pads made for back of the envelope or napkin design work. They would, of course, consist of napkins and used envelopes.

At some point, any such design would go into Solidworks, because I need the practice, I own a copy, and it's more popular than another product I like. I think the latter is called Creo these days, but it may have moved on to yet another name, or maybe it's been revised out of recognition. It's previously been known as ME30, CoCreate, and I think something else besides Creo. Parametric aka PTC owned it the last time I checked. They used to have a crippled version available for free. It couldn't do assemblies with more than 60 parts, and some of the gee whiz functions were crippled to. But it might be handy even then.

As Mad Mac notes, CAD can use up a LOT of time if you're not used to it. In my experience, Solidworks can do this more than Creo, because you have to learn which features shouldn't be used. Those features can lock things up pretty well. I've had trouble using too many relations (or I think that's what they're called) in assemblies. Solidworks is very much like programs written by Microsoft. The default is to have all the bells and whistles turned on, and you can use a lot of time figuring out how to turn off the ones that get in the way. I found AutoCAD annoying, even after taking a class. I guess I was spoiled by ME10 many years ago. It was linked with ME30, but could also be used on its own for 2D stuff. I remember it as quite intuitive, but maybe that's only after I had a fair amount of work experience with it.
 

BBerson

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I use erasers more than anything, have several sizes.
And the 11x11" white envelopes junk mail comes in are nice. Leave it unopened , it's stiff enough to draw in your lap.
X-Plane was useful. But not much anymore, it takes too much time.
 

skier

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Mar 5, 2008
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CT
Pen & Paper
Excel
GNU Octave (open source Matlab)
Solidworks (through EAA Membership)
 

Pops

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A roll of masking paper from the auto paint store is to costly. Get a roll of paint masking paper to draw your working plans on from the aircraft supply box store call Lowes, in the household paint dept. About 1/2 price of the auto paint store.

Friend of mine in WY drew the tubing with chalk on his garage floor and used bricks to hold the tubing while tacking up for his 4 seat Bearhawk. Got down on his knees and tacked with a steel plate over the concrete. After welding he used a torch and hammer and made some adjustments, Looked good and flew very well.
 

Swampyankee

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Dec 25, 2015
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Well, the last time I was seriously trying to work out a design was about 30 years ago. My tools were a decent drafting board, a decent set of instruments (Riefler, not the super-best, but decent), an HP-67 calculator, a good set of triangles and ships' curves, and a template of a 50th percentile adult male.

I also got an installation drawing for an O-320 from Lycoming. A full-scale installation drawing. I wish I still had it -- it was about 6 ft by 12 ft.

As an aside, lofting was still practiced into late 1980s in the aircraft industry. Slightly earlier, an engineer I worked with had worked at Dehavilland Aircraft (the one in Hatfield....), where they drew aircraft full scale. He said they used aluminum sheet and 9H pencils, wearing slippers (I can't remember if they were felt or deerskin) to move around on the drawings.
 

Aerowerx

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Graph paper (4 squares per inch) , pencil (mechanical, with 0.7mm lead. Prefer 0.5mm but it breaks too easily), Excel, and XFLR5.

I've always had trouble with CAD programs. I can never make the electrons go where I want. With a CAD program you are limited to what the programmer allowed, but with a pencil you are limited only by your imagination.
 
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