Nosecone and transition 3D model generators for openSCAD

Feedback welcome. The free openSCAD app for Mac, Windows, and Linux can be downloaded here:

https://www.openscad.org/downloads.html

View attachment Nose Cone and Transition 3D Model Generators v4.zip

In v2.01, I've made nosecone type selection easier.

In v3, I've added spherically blunted conical and bi-conic. Later will be an elliptical nc generator and a fin generator.

Optimal Nose Cones
• Subsonic – Elliptical (remaining to be done)

Optimal Fins (I'll follow this list)
• Fin Count of 3
• Fin Joints 4% to 8% of Root Cord
&#8226; Thickness < 10% of Root Cord often between 3% & 6%
&#8226; Trailing Edge Flat but < 0.7% of Root Cord in Thickness
&#8226; Leading Edge may be Sharp
&#8226; Sweep Angle between 45° and 70°
&#8226; Flat Fin Tips
&#8226; Hexagonal Cross Section
&#8226; Clipped Delta Shape

The above lists are from this excellent PDF "Nose Cone & Fin Optimization":

https://www.offwegorocketry.com/userfiles/file/Nose Cone & Fin Optimization.pdf

I have also made my own OpenScad noise cone.
See printed noise cone below

I am attaching all my OpenScad files, they need to be tidy up
View attachment noisecone_src.zip
I have the following noise cone (equations are from Wikipedia):
- power series
- eliptical
- secant
- tangent

bdureau said:

I am attaching all my OpenScad files, they need to be tidy up
View attachment 267816
I have the following noise cone (equations are from Wikipedia):
- power series
- eliptical
- secant
- tangent

Click to expand...

Nice. I've had an elliptical "done" for about a week now and while it preview renders perfectly, I get an error on full render that was associated in previous releases of openSCAD with a renderer bug or due to a discontinuity (gap) in the solid. I don't have the latter as far as I can see or determine from echos. A shame since the elliptical with a fineness of 2 is the best for subsonic rockets. Will continue to work on it and other items on and off.

Final version (v4) of nose cone and transition 3D model creation openSCAD files found above. Elliptical nose cone generator now included and bug fixes made. This concludes this effort.

Next effort will be fin-related generators.

3D printed 29mm von Karman nose cone.

Latest version of the OpenSCAD rocketry scripts collection.

I am also a big fan of OpenScad and I do all my rockets designs with it
I use it for my mini CNC as well as my 3D printers

bdureau said:

I am also a big fan of OpenScad and I do all my rockets designs with it
I use it for my mini CNC as well as my 3D printers

Click to expand...

Which mini-CNC do you own? I was thinking of buying one of the really small ones that are relatively cheap. I recently bought one of the $75 1W laser engravers which use CD/CD-ROM laser transports for accurate, stepper motor controlled X & Y movement. I plan to try to use it for PCB resist removal just for the heck of it even though I have no problem making 10 mil traces reliably enough using the toner transfer method.

Thanks. Great find.

I use OpenSCAD for everything...

Folks need to know that OpenSCAD is free and absurdly easy to install on just about any platform... www.openscad.org And, it's absurdly easy to open an example file and fiddle with it. In the case of Winston's files and the attached example of my own, you just open the file and change the parameters in the built-in text editor. F5 previews the changes, F6 renders them (necessary to export), then you can File/Export the object as an .stl or other formats. Learning the actual programming syntax is a little more involved but it can be picked up pretty quickly with some experimentation. Unfortunately, the least attractive parts of OpenSCAD are the usually obscure error messages and the lack of an integrated help function - you have to search the web page manual for help with anything.

BTW Chuck, the forum doesn't allow upload of files with the .scad extension. Not a big deal, easy enough to zip it first - but an extra step for something that is usually just a small ascii text file.

Model Rocket Fin Can - Trapezoidal Fins - Configurable

Note also, that the Rocket CAD Repository has quite a few OpenSCAD files, including my own transition generator. I guess I need to put some of that stuff on Thingiverse.

That repository is sort of a fragile thing, depending upon an individual to keep a shared Dropbox folder open. We'd talked a few months ago about a Forum CAD file section - any movement on that?

is there an interest in a repository that is a bit more stable?

Also, the existing Repository doesn't get much activity (or any, lately), because everyone routinely forgets (or never knows about) its existence. Something with more visibility would make it more useful.

.scad has now been added to the list of file extensions that can be uploaded.

Angie said:

.scad has now been added to the list of file extensions that can be uploaded.

Click to expand...

Thanks!

That Fin Can Thing that I mentioned earlier in this thread, well yesterday I updated it to include many more pre-made fin can configurations.

Then I found something in OpenSCAD that I hadn't noticed before. There is an OpenSCAD Customizer (not the Thingiverse Customizer) that allows Windows-style controls to be used within OpenSCAD to select parameters, rather than having to edit them in the source code. The user still has to install OpenSCAD and there is a bit of set-up to do that is detailed in the file and in the notes on Thingiverse.

https://www.thingiverse.com/thing:2954100

Winston said:

Which mini-CNC do you own? I was thinking of buying one of the really small ones that are relatively cheap. I recently bought one of the $75 1W laser engravers which use CD/CD-ROM laser transports for accurate, stepper motor controlled X & Y movement. I plan to try to use it for PCB resist removal just for the heck of it even though I have no problem making 10 mil traces reliably enough using the toner transfer method.

Click to expand...

I have the 3018
https://fr.aliexpress.com/store/group/CNC-2417/424291_256640639.html
It is good to do my elec bay, centering rings or fins

This really good to lean how to use a CNC, you can do plywood, epoxy or plastic but going forward I am thinking building a bigger one
https://www.makerfr.com/cnc/rs-cnc/presentation-rs-cnc/
According to the designer of the RS CNC it cost less than 400 euros to build and you should be able to do metal

For those interested the source code for my elec bay can be found on my gihub
https://github.com/bdureau/Model-Rocket-3D-files-/tree/master/payload_plate
those are parametric and have the foot print for all my altimeters
you can CNC the plate or 3D print it if you have a large printer

Working on the OpenSCAD Customizer Fin Can Thing that I mentioned earlier in this thread got me to take another look at a transition component generator that I had done some time ago. I had never posted it earlier because I'd included so many features in it that it was really too complex to expect anyone to edit the parameters in the OpenSCAD file. The Customizer makes those parameters accessible. The features include:

* Conventional upper and lower shoulders.
* Optional inset smooth shock chord attachment point.
* Optional center holes for screw attachment.
* Optional ducted through version for gas flow or weight reduction.
* Optional cylindrical sections above or below the transition.
* Optional tube 'socket' instead of shoulder on smaller diameter end.
* Optional shoulder edge bevel.
* Available print support for transition/shoulder rim.
* Available cross-section or 3/4 views to view internal structure for development.

The user still has to install OpenSCAD and there is a bit of set-up to do that is detailed in the file and in the notes on Thingiverse. I'm hoping folks will find it worth that little trouble.

https://www.thingiverse.com/thing:3104666

I did not know about the OpenScad customizer until yesterday, I have installed the dev version of Openscad and I will have a look at it to see how it works.
Looks like there are some cool features coming up such as svg import (I have tested it and it works) which mean you should be able to import some drawings and extrude them. I have always had troubles converting things to dxf

bdureau said:

I have the 3018
https://fr.aliexpress.com/store/group/CNC-2417/424291_256640639.html

Click to expand...

Thanks for the info. I was considering the CNC 2417 or 2418 and didn't even know about a 3018. Another one to consider.

vcp said:

The user still has to install OpenSCAD and there is a bit of set-up to do that is detailed in the file and in the notes on Thingiverse. I'm hoping folks will find it worth that little trouble.

https://www.thingiverse.com/thing:3104666

Click to expand...

Nice work! Thanks.

OpenSCAD scripts for model rocketry v3 - minor bug fix, nosecone/tailcone option added, hemispherical top to nose cone anchor holes to eliminate need for supports, added delta/clipped delta fin can generator with integrated launch lug option. All resulting STLs from all scripts should be printable without supports as that was the intent.

Being an Onshape user, I came up with a NC generator for that tool. You have to have an OnShape Account to use it. It does several types of NC, sold or thin-walled, and Chamfer bottom edges. Some of the range checking is pretty fragile yet, so different combinations of things will break it (hope to make it more robust over time)

https://cad.onshape.com/documents/7...0c757d470539db7bb9/e/34e4e04de7bf18d0d8a99200

curtisheisey said:

Being an Onshape user, I came up with a NC generator for that tool. You have to have an OnShape Account to use it. It does several types of NC, sold or thin-walled, and Chamfer bottom edges. Some of the range checking is pretty fragile yet, so different combinations of things will break it (hope to make it more robust over time)

Click to expand...

Beautiful. I established a free account, but can view only, not edit the nose cone shown at the link.

Winston said:

Beautiful. I established a free account, but can view only, not edit the nose cone shown at the link.

Click to expand...

I meant to say beautiful work. Is the view only limitation a characteristic of free accounts?