Fully parametric ogive nose cone with a screw-on base. This allows the nosecone to be entirely printed, and used as a small payload bay. The ogive shape is created by revolving a circular arc, combined with a spherical tip. Uses syvwlch's thread library. More parametric model rocket parts to come. Default size is for some extra thin-walled 1.63"/41.5mm diameter cardboard body tube I have. Includes integrated reinforcement bar and mounting holes for tying a shock cord to the base.
Now available at Github: https://github.com/bld/Parametric-Threaded-Ogive-Rocket-Nose-Cone
- Download syvwlch's Screw Library: http://www.thingiverse.com/thing:8793
- Measure body tube inner & outer diameters and enter
- Select other parameters
- Render & export STL for "fitcheck" part
- Print fitcheck.stl and check fit in body tube. It shouldn't be too tight or too loose. You want it to come loose easily with the ejection charge, but not rattle around.
- Adjust & reprint if necessary.
- Print nosecone and base once the fitcheck part works to your liking.
- Thread shock cord through holes in base and tie.
- Screw cone onto base.
I printed this on my Makergear Mosaic with the following Slic3r settings:
- No support material
- 0.25 mm layer thickness
- 3 solid layers, 2 perimeters
- 0.1 fill density with rectilinear fill
- The threads tend to curl up a little while printing at 0.25 mm, but the base and cone do so equally so the threaded together without trouble.
- Due to some slack in the threads, the base can end up slightly off-center when tightened. Unscrew and rescrew pressing away from the side that's short.
- Mine came out a little heavy, so for smaller, lighter rockets, check the balance to make sure it isn't too nose heavy: http://www.wikihow.com/Calculate-Stability-of-a-Model-Rocket