Thread Tools
Jan 15, 2011, 06:17 PM
Registered User
ashdec87's Avatar
Thread OP
Discussion

Designing an airframe?


Hey,

I'm trying to design a Shadow 200 for a scratch build. I've got AutoCAD for mac and have made up a nice external model. But will this software make up formers for me to print off?

I might get autoCAD inventor so I can test out flap designs and such. Any other ideas?

I like these programs because I can get them for free as a student..

thanks

ash
Sign up now
to remove ads between posts
Jan 15, 2011, 08:15 PM
Jim C Patrick
jcpatrick's Avatar
When you say you might get Inventor to test flap designs, it implies an extra week or so. How much time do you want to design? There are many ways to approach this, but the quickest way to make a model is far, far different than a completed set of manufacturing plans.

What materials and construction methods? Are you trying for a 4M full-scale or a 24 inch park flyer? What foils are you using? The NACA 4415 used on the Shadow is (close to but) not flat-bottomed and complicates construction. Is the 'nice external model' a solid model, surface model, or 3-view linework?

You asked "will this software make up formers for me to print off?", and the answer is both 'yes' and 'no', depending on what you have, what you intend to do, and a lot of other variables. So tell us some more....
Jan 15, 2011, 08:49 PM
Registered User
ashdec87's Avatar
Thread OP
lol thanks for the reply.

I'm not in any hurry to make the plane. I'm enjoying the designing stage.

I'm shooting for an 80 inch range for the wingspan, and everything else is being scaled from there. As for the foil. That's yet to be decided, I want it to be a stable and moderately slow plane.

So far I have a wireframe model that can be changed to a surface model (cross section is hollow). I intend to make the plane from with foam formers, foam skin. If needed, a thin layer of FG can be added to the exterior for strength, but I doubt that'll be needed.

Wings will be a foam/FG/CF/lite ply mixture. Spar will be foam with CF caps. Wing joiners will be ply/CF. fiberglass is for strength if needed.

What I need from the software is some printed cross sections so I can trace out the formers. I'm pretty new to CADs so I'm not 100% sure how to do that. What I would really like is for it to break the plane down to, say 10, cross sections and lay them out for printing..

I attached what I have so far.
Jan 15, 2011, 10:46 PM
Jim C Patrick
jcpatrick's Avatar
You might contact Chris Good for ideas, since he is currently one of the the designer Principal Systems Engineer/Lead Avionics Engineer for the Shadow. Chris has a great build page for a Shadow model almost (not quite, just 77") the same size as yours. Since he really builds them, he used the real blueprints and the model is a true half-scale.

Back to your model for the moment. For solids, cross sections can be gotten from a flat plane intersecting the fuse. SECTION or SLICE are those commands, and I prefer SLICE if you need a flat cross-section to work with. Draw > Solids > Slice.

To be embarrassingly open, I never worked with surfaces in Autocad, always used solids because they exported to CAM formats. But if you can export or save the surface model, Sketchup will import it with the DWG/DXF plugin, and then you can section and slice to your hearts content there.
Jan 16, 2011, 05:15 AM
Registered User
first what version of autocad do you have
drawing 3D models rhino is good and they have student versions.

NO but you can cut formers from models with autocad
there is a program writing software in acad for automating drawing called (autolisp) it is possible to wright a command to cut formers from a model

most draw 2D plan and elevation and draw formers from that.

have a look at for rhino modeling https://www.rcgroups.com/forums/show....php?t=1357922


Quote:
Originally Posted by ashdec87
Hey,

I'm trying to design a Shadow 200 for a scratch build. I've got AutoCAD for mac and have made up a nice external model. But will this software make up formers for me to print off?

I might get autoCAD inventor so I can test out flap designs and such. Any other ideas?

I like these programs because I can get them for free as a student..

thanks

ash
Last edited by dpot; Jan 08, 2019 at 11:52 AM.
Jan 16, 2011, 02:03 PM
Registered User
ashdec87's Avatar
Thread OP
Hmm thanks for the tips. I'd like to stick with the program I have and work with that. Mainly because I already have this rendering, it would be a lot of work to redraw it.

As for the version I have. Its simply called autoCAD for mac. Here's a link.

http://usa.autodesk.com/adsk/servlet...&siteID=123112

I'll see if I can play around with it and come up with something.

Right now I'm working on a detailed rendering of the equipment tray along with the support for the wing and spar in the rear of the fus.
Jan 17, 2011, 10:10 AM
Registered User
i think it is acad 2011 i am using acad 2010


Quick Reply
Message:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Sidekick MK II, an FPV plane I'm designing. AleG FPV Aircraft 44 Nov 14, 2011 10:57 AM
For Sale Blade 400 with a ton of extrasand an extra airframe jdlfreedom Aircraft - Electric - Helis (FS/W) 3 Sep 24, 2010 12:13 AM
Wanted FW-35A lightning Airframe (or an Airframe for its powerplant) Sherlock Aircraft - Electric - Jets (FS/W) 3 Aug 08, 2009 12:03 AM
Discussion Designing my own airframe...... Upside-Down Indoor Pattern/F3P 10 Jan 27, 2008 08:39 PM
Designing an aircraft from scratch - How To? jzen Power Systems 9 Jun 08, 2001 05:45 AM