Flaky Lightweight Rocket

An update to my previous Big Flaky Rocket model.

I have reworked the snap-fit system to make it better, and more tolerant to multiple assembly / disassembly cycles, making it more usable as a toy. I also further decomposed the bottom part by splitting the legs and feet, allowing a larger printing scale (I tested up to a 80cm version, but 120cm would be doable with a standard-sized printer).

The rocket shape is still the one published by Pierre Muth, based on previous work by Gregory Vienot. Only the assembly system is mine.

Choosing a configuration / Customizing

The OpenSCAD design is parametric, and can be used for a wide range of scales. I printed it as small as 15cm, and as large as 80cm (plus the antenna). STL files for predefined sizes are included as archives for convenience, but if you want a specific size or need to adjust tolerances, you will need to re-generate them.

The parameters are specified in file common.scad. A number of configurations are included, just uncomment the relevant part. You can of course make your own, for example by just changing the rocket_height parameter. A Makefile can be used to generate the STL files. The Makefile also needs to be tuned according to the size and parts to print (see bellow).

For smaller sizes, the bottom must be printed as a single part with the legs and feet. Starting with 23cm, the legs can be split (but not the feet). At 35cm, the feet can be split too. You should set the BOTTOM_PARTS variable accordingly in the Makefile (uncomment the corresponding line).

For larger versions, additional "floor" parts can be printed to strengthen the structure. They are not mandatory (and can be added afterwards) but make the body significantly more rigid, and only weight a few grams. Just uncomment the FLOORS line to generate them. Finally, if you need the antenna, uncomment it too.

Many parameters can be tuned in common.scad (all design variables can be overridden here as this file is always included last). In addition to rocket size, you can adjust the hooks count and dimensions, play with the many tolerances parameters, and change the position and orientation of the cuts when printing the legs / feet separately. For example I used it to cut the legs at the very base of the body in the largest version (because I wanted to make the leg white), but I would not really recommend that choice as it makes the bottom part more fragile. Also, if you want a rounded top (too avoid a too sharp part), you can set tip_radius to a positive value.

Printing

I designed the tiles to be two lines thick (though this can be customized), so that they can be printed with only one perimeter, no top/bottom, and no infill, except for the top hook (using a modifier). Print all male tiles white and all female tiles red (or any color you like), three times each. The top part can be printed in the same way.

For the bottom part(s), I recommend 2 perimeters and some infill (possibly very little) for a better outer surface quality (and for strength, if the bottom is split in multiple parts). But the complete bottom with legs and feet can be printed with only one perimeter.

Supports will only be required for the bottom part (if printing the legs together, upside down), only between the hooks.

I printed the floor parts without bottom/top, with only a triangular infill.

And if you print the antenna ring, you will need a 4cm straight portion of red filament for the tip !

Category: Scans & Replicas