As a very short project that will keep my busy while weather and parts still shipping are preventing me from working on the Boxman arcade cabinet, I decided to design a model rocket in Onshape that is entirely able to be 3D printed.

So, I decided to go with a modular system of pieces that slide together. I figured that would be easy to design and would just be a question of tolerances. The Onshape document is here.

For any of these models there are variables on the left-hand panel that you can change which will change the sketch. They are nicely labeled with things like "engineOD" and "bodyDia" which should make it very user-friendly.

The way this works is that you can print out as many "Outer Body" pieces and "Coupler" pieces you want which will make your rocket longer. The couplers fit inside the outer body pieces very snugly (you may have to bend the couplers in a bit to get them to go in but once they're in you can pop them back to the right shape and should be able to slide it the rest of the way.) You print out one "Engine Housing" piece after you adjust the variable to fit the engine you plan to use. Tolerances are included in the sketch, you literally just have to measure your engine's OD and type it in. Print out 2 of the "Engine Casing Mount" pieces which will slide over your engine housing piece and slide into the outer body pieces snugly. Then you just need to print out the fins with the flange facing down (the overhang is only 30º which most printers can handle I think) and the nose cone which also needs a coupler to attatch. If you wish to add launch lugs (recommended) those are also available. They print vertically with the non-chamfered side down. DO NOT print them horizontally on the seemingly flat side as it is actually curved based on the bodyDia variable so that it hugs the outer body pieces.

All of these pieces can be glued together and you should have yourself a nice model rocket! I have yet to actually launch one but I will definitely post a video when I do. The document right now is designed to fit a D-size Estes rocket engine (24mm diameter)

I will be updating the parts on this document as new things come up in terms of design flaws. Hopefully with the spring weather coming I should be able to launch one off pretty soon! Any suggestions for design are welcome

EDIT:: forgot to include how to print each of the pieces haha
Everything is 0.2mm layer height.

Outer Body: Vase mode (0.4mm wall, no infill, no top or bottom fills)
Coupler: Vase mode ^^
Engine Housing: Vase mode ^^
Nose Cone: Vase mode ^^
Engine Casing Mount : 0.4mm wall, no top or bottom fills, 30% infill
Fins: 0.4mm wall, YES top and bottom fills, 10% infill.
Launch Lug: same as fins

This sounds sweet!

One of my IRL friends (Drewster, in this case) just showed me the other day his own copy of the Falcon Heavy. Maybe I can persuade him to make his own thread!

In case there was any confusion about the engine casing part of this I've taken a few pictures of the steps. I did use a bit of electrical tape (yes, this was designed ) to widen the bits of the housing so the mounts fit very firmly on. Anyway, here are the steps




I also discovered upon gluing on the fins that is incredibly difficult to get them exactly 120º apart from each other (I did a particularly poor job ) so I have created a new part in the Onshape document called "Outer Body w/ fin channels" which basically just has indentations along the length of it that the fin flanges fit into which aligns them. I'm not sure if the regular coupler will fit inside this piece, but if not I'll make a new coupler that will. That's all for now.

EDIT:: So, the coupler piece still fits inside but the engine casing mounts don't fit inside without bulging out the grooves. so I have updated that part with notches that fit around the ones on the fin body.

I have finished my first prototype (actually a couple days ago but now I can post about it)

Here is what it looks like!

I do want to see if I can paint it bright red and yellow, but on black PLA i don't know how that's going to work.

Unfortunately I had no yellow paint, but I did have gray primer, so in the spirit of Cemetech I painted it red on the nose-cone assembly and gray on the rest. I'm really happy with how this turned out and like I said before I will definitely post a video when we launch it when the weather gets nice and the ground gets dry. Here's a picture!

This looks really cool! When are you planning to attack cows?

Haha hopefully not but in Iowa there's a cow every time you turn around in the country which is where we'll have to launch it, so I'll keep y'all updated on the cow situation.