# What software do you use?

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by Zzyzxx71, Jan 7, 2009.

### Help Support HomeBuiltAirplanes Forum by donating:

1. Dec 17, 2009

### orion

#### Well-Known Member

Joined:
Mar 3, 2003
Messages:
5,800
135
Location:
Western Washington
I'd be willing to bet that mechanical shapes are probably created in a bit more optimal fashion in a package like SW since that was originally developed as more of a mechanical design product. The demo I saw concentrated more on "styling" rather than mechanical development. Since things like auto-body development and airplane lofting both fall under more of a styling category, the demo was a bit more appropriate for that end use.

2. Dec 18, 2009

### Dana

#### Super ModeratorStaff Member

Joined:
Apr 4, 2007
Messages:
8,689
3,066
Location:
CT, USA
I've never used CATIA, but by all accouts it's an excellent package for aircraft design (that's what, after all, it was made for), but it's out of reach (financially and in terms of complexity) for 99.9% of the users here.

At the risk of repeating myself, the parametric solid modelers are wonderful when you have the design pretty much worked out before you start modeling it, and/or when you expect to make many minor revisions later. They're much less useful for doing preliminary design where you're likely to make large sweeping changes as the design progresses... you may find yourself boxed into a corner by the original base constraints you chose and have to start the modeling again from scratch. With the direct modelers, you can't change a parameter and watch the changes ripple through the design automatically, but you can chop off half a design and replace it with something completely different without any difficulty, and the initial modeling goes a lot quicker because you don't have to set up constraints and everything.

-Dana

Exceeding the legal fun limit on a regular basis!

3. Dec 18, 2009

### Woodenwings

#### Well-Known Member

Joined:
Aug 2, 2006
Messages:
164
5
Location:
Toronto
Hi Dana

I agree and disagree. I can model up a whole plane in a few days without any constraints and then push and pull to my heart's content.

After that I can constrain things as I choose. The way you design a thing is very much left in the hands of the designer. I will also make several iterations that I can return to if I F**K up. I find the lack of "hard constraints" disconcerting.

I also have designed many a thing (that will be later handled in the computer by others) where I break all associativness to ensure that they don't inadvertently screw it up and blame me.

Solidworks is cheaper than Catia and easier to use. It sells for around 3K to 1.5K depending on options. it's worth it!

4. Dec 19, 2009

### flywulf

#### Well-Known Member

Joined:
Dec 22, 2008
Messages:
109
1
Location:
Los Angeles California USA
Would anybody care to share what they paid for a copy of Solidworks?

ED

5. Dec 19, 2009

### Dana

Joined:
Apr 4, 2007
Messages:
8,689
3,066
Location:
CT, USA
Solidworks is in the $3-4000 range. -Dana 1. Programmers are expensive. 2. Press releases are cheap. 3. Therefore, it's cheaper to explain the bug than to fix it. 6. Dec 19, 2009 ### flywulf ### flywulf #### Well-Known Member Joined: Dec 22, 2008 Messages: 109 Likes Received: 1 Location: Los Angeles California USA Ouch! that hurt, what a buzz kill. Ed 7. Dec 19, 2009 ### flywulf ### flywulf #### Well-Known Member Joined: Dec 22, 2008 Messages: 109 Likes Received: 1 Location: Los Angeles California USA Hello Rhino! Ed 8. Dec 19, 2009 ### Mac790 ### Mac790 #### Well-Known Member Joined: Jun 22, 2008 Messages: 1,529 Likes Received: 19 Location: Poznan, Poland Dana, you have old prices, current 2009 version prices are 4995$-7495$. But I would say it's worth every$, it's really good software.

Software Review: SolidWorks 2009 Pulls Out All the Stops | Machine Design

Seb

9. Dec 19, 2009

### Dana

#### Super ModeratorStaff Member

Joined:
Apr 4, 2007
Messages:
8,689
3,066
Location:
CT, USA
I'll stick with KeyCreator, thank'ya very much. SWX is indeed good software, but also very cumbersome for the kind of design work I do. But as I said earlier, if I were starting from scratch on a limited budget, I'd get the free version of CoCreate.

-Dana

"Naked" means you ain't got no clothes on; "nekkid" means you ain't got no clothes on - and are up to somethin'.

10. Dec 20, 2009

#### Moderator

Joined:
Jul 8, 2009
Messages:
10,732
2,542
Location:
Rotterdam, Netherlands
Any ideas about flutter and stress calculations? I'm particularly interested in the first since that's a pretty impossible job to do easily by hand/excel/java/mathlab.

Any thoughts?

11. Dec 20, 2009

### orion

#### Well-Known Member

Joined:
Mar 3, 2003
Messages:
5,800
135
Location:
Western Washington
There are quite a few FEA systems out there that will do a reasonable job of doing stress analysis. But the list gets considerably smaller if you're looking for a package that does composites, especially if you're looking for one that is relatively user friendly. Personally, I use COSMOS/M, which BTW I consider downright user hostile. But it does a fairly good job of handling composite structures so I've kept at it for all these years.

I am probably going to change to something better and so far it looks like Strand7 is going to be my package of choice. I am also looking at several Nastran derivatives but given that the analysis side is relatively consistent from one to the other, it's the user interface that will most likely drive my decision more than anything else.

As far as flutter is concerned, I would leave that to someone who is well versed in the science and who has a verifiable track record of experience. This is nearly a black art and certainly nothing that I would leave to chance if it's something that you're really concerned with. To the best of my knowledge, there is no package out there (at least not in the affordable public domain) that has the ability to do complete flutter analysis and I would have serious reservations about anyone or anything claiming otherwise.

12. Dec 21, 2009

#### Moderator

Joined:
Jul 8, 2009
Messages:
10,732
2,542
Location:
Rotterdam, Netherlands
I agree on that point.
Do you consider yourself to be enough of an expert to analyze flutter behavior of the typical high-end homebuilt or do you outsource this too?

For a 250 KTS IAS VNE composite aircraft, would it be advisable to just design for the basic flutter cases (different frequencies, springconstant and stiffness ok) and make sure they're far away from your VNE?

13. Dec 21, 2009

### orion

#### Well-Known Member

Joined:
Mar 3, 2003
Messages:
5,800
135
Location:
Western Washington
No, I do not consider myself to be a flutter analysis expert. I know how to design for it (or against it) but do defer to others in their expertise to model and analyze said behavior.

Regarding the aircraft, for that speed range and normal Part 23 derived loadings, no, I personally would not be too concerned with flutter. But that is based on my own experience - I think that if a designer does not have a significant background in designing for this speed range it might be pertinent to undertake some level of flutter analysis or ground vibration testing to verify the design assumptions.

14. Dec 21, 2009

### Mac790

#### Well-Known Member

Joined:
Jun 22, 2008
Messages:
1,529
19
Location:
Poznan, Poland
If you are talking about flutter analysis, aeroelasticity, etc, check out this, unfortunately it's in Polish (maybe they will add also English version in few weeks), anyway it's a project made by students in my UNI (they are one year higher than I). In short first they created a 3-D model, based on a wind tunnel model (they used 3-D scanners) for CFD analysis, next they created a structural equivalent of the original plane in Solidworks/Femap, I would really like to say you more about it, but with my sh^ English I'm not able.

So, for a few pictures check out this page. I won't post those pictures here without their permission.
IWP – InÅ¼ynieria Wirtualna Projektowania » Projekt “Iryda”

Seb

Last edited: Dec 21, 2009
15. Dec 22, 2009

### ultralajt

#### Well-Known Member

Joined:
May 10, 2009
Messages:
1,566
750
Location:
Slovenia
My Polish/English on-line translator says:

16. Dec 22, 2009

### Mac790

#### Well-Known Member

Joined:
Jun 22, 2008
Messages:
1,529
19
Location:
Poznan, Poland
Mitja,

I never translate foreign pages (French, German, etc) into Polish with on-line translators. I always translate them into English, because usually I'm not happy with results, but this translation wasn't very bad.

Just a few more words/sentences:

niskowymiarowego- low dimensional
model belkowego- beam model
Aeroelastyka/aerosprężystość- aeroelasticity
Iridium - Iryda (plane name)
rozwiązywaliśmy- we were solving

In Warsaw, trying to flatterowych in the wind tunnel model was flatterowy - this one is a mess, in short it means, that a flutter model was created for the flutter test.

17. Feb 6, 2010

### ultralajt

#### Well-Known Member

Joined:
May 10, 2009
Messages:
1,566
750
Location:
Slovenia
My latest work in Rhino:

Gnome Omega rotary engine from 1912 (it is not yet finished.. work in progress):

Mitja

Last edited by a moderator: Mar 20, 2019
18. Feb 6, 2010

### Mac790

#### Well-Known Member

Joined:
Jun 22, 2008
Messages:
1,529
19
Location:
Poznan, Poland
19. Feb 6, 2010

### ultralajt

#### Well-Known Member

Joined:
May 10, 2009
Messages:
1,566
750
Location:
Slovenia
WOW Seb! Thanks for the link to your work! It is amazing!
Pretty poster!!

Yes, I have Deja Vu also...found on one russian forum, so that was the reason to start playing with the engine...making one part after another...

Mitja

20. Feb 7, 2010

Joined:
Apr 4, 2007
Messages:
8,689