Design/Build thread - "You Want to do What?" - 3D printed fincan and nosecone through Mach 1 on an L1000

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Dustin Lobner

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Hi everyone,

I'm working on another rocket with a 3D printed fincan/motor mount. I launched on a J450 last year without issue, and am aiming for a similar flight on a K535 at Mini Midwest Power in May on that same rocket....assuming that goes well, the build on this thread will be the next step up the power ladder. The goal is to use an L1000 to push it through the sound barrier. Current SWAG numbers put into RockSim show Mach 1.3 and 12k feet. Tentative launch date of Midwest Power at the end of October.

Here's the J450:

BasketCase.jpg

The general idea is something similar - a 3" diameter, give or take 7' tall. The fins will be smaller and stiffer than the J450 rocket and the nosecone will be longer/pointier. Will fly on an Eggtimer Proton, Eggtimer GPS for tracking, and a camera or two hopefully.

I have been thinking about motor retention because I'm trying to make the bottom of the fincan as boat-tail-y as possible (see pics below for rough draft). I think what I'm going to do is epoxy a 3D printed ring on the forward end of the motor casing, and then put bolts through the wall directly into that ring. For space saving and quick decent, I'm thinking drogue-less, just pop the back tube off of it so it doesn't come down ballistic.

For color, the whole middle of the rocket (tubes and electronics bay) will either be printed red or red fiberglass sock from Soller Composites. For the fincan and nosecone, I'm going to do a transition to blue, so the very bottom and top of the rocket are blue, and then it transitions like below. Just bought a Palette 2 from Mosaic, so going to use it to do transitions like that.

Capture.PNG


First cut on the fincan/MMT:

Fincan 1.PNGFincan 2.PNGFincan 3.PNGFincan 4.PNG


The hardest part of that I think is going to be printing it without it falling over. Thinking I'm going to print it upside down so it has a wider base of support...and probably going to slow it way the heck down too. Just exported the STL for grins - 275MB, lol. I'm also going to finish all the 3D printed parts with XTC-3D epoxy so they're smooth, hopefully giving better aerodynamics than a barn, which is what my usual 3D printed parts are.


First open question at the moment is if I'm going to use LOC cardboard tubing, how many layers of glass do I need? Soller has sock in 10oz for this size, so I'm thinking either 2 or 3 layers.
 

Dustin Lobner

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Question - has anyone done something like an L1000 with a flyaway rail guide? I would love to not have buttons on this thing if at all possible.
 

Dipstick

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Cool project! Two layers of glass is usually the most you need, any more is really extra weight with diminishing benefit.
 

Dustin Lobner

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Cool project! Two layers of glass is usually the most you need, any more is really extra weight with diminishing benefit.
Sounds good. I won't be sanding it either, so won't be compromising the outer layer. EDIT - I have an email in to Additive Manufacturing to see if their 3" fly away rail guide will accommodate 3" + 2 layers of glass.
 
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