3D Printing Estes #1301 R2-D2 fins for printing

Gunstar

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https://www.thingiverse.com/thing:5462500

The Estes #1301 R2-D2 model rocket is a cool model rocket, but it has some flaws. First, it is underpowered, upgrading the motor mount to take 24mm D engines is a good move. Second, the fins that attach to the legs are a bit too flexible and WAY too brittle. Breaking a fin on landing is a very common thing, and replacements are hard to come by. Third, it is barely stable, you can improve it with extra weight in the dome, but that cuts your altitude.

These fins will hopefully fix the last two issues. You can now 3D print replacement fins that will be stronger and more durable than the originals.

I've included 2 styles, one that matches the design of the original fin, and an alternate design that should move the CP further back, increasing stability.

Please note that I have not flight tested either of these yet, and they do add some extra weight over the original fins, so you use them at your own risk. Do some testing first to ensure a stable flight. If there are issues with them let me know and I'll make modifications.

For printing I recommend you orient the fins upright so the layers will be perpendicular to the direction of flight. You will need supports for the peg that fits into the leg, but block supports from forming inside the hole for the screw. The screw from the original fins will work fine and self-thread into the hole.
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Gunstar

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UPDATE
After further print testing, I found the alternate design prints better as 2 parts. It will use less material and I put a bevel on the leading edges. I've added those parts to this thing.

When printing the 2 part fin I lay them flat with no rotation as in the picture. I used a layer heights of 0.2, and no supports. I set the slicer to have 3 bottom layers and 3 top layers This results in one layer of infill which makes for better top layers than having no infill layers. Infill was at 40%, cubic. I set the line direction as [0,90] so the top and bottom faces have a print direction that matches the airflow direction. Warping was not an issue for me so no raft or brim. The side fin should fit easily into the slot on the main fin for gluing.

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