I'm designing and flying a 3D printed (about 90-99% printed) high power rocket for my NAR level 1 cert attempt and possibly reuse the design for my L2. I do have experience in 3D printing and model rocketry, just not combined. So the design might not be perfect...
Why 3D Printing?
I wanted to do 3D printing because it affords greater complexity in aerodynamics, and the ease of reproducibility, not only of results but of the actual air-frame. Also, its not generally done so that's all the more reason to try!
Whats NAR?
NAR is the National Rocketry Association, they are a cub for model and high power rocketry.
The certification process is in 3 stages, and basically you have to build a rocket that successfully flies with the appropriate size motor. (more details of the actual process are on their website).
Files
body tube (split joint upper)(threaded).STL
Standard Tesselated Geometry -
689.05 kB -
11/21/2019 at 19:32
This is about the top third of the rocket with the nosecone screwed into the payload bay and the parachute bay slid onto the bottom of that. These sections fit quite nicely together with minimal finishing.
Getting started on printing some if the parts I was most concerned about.
One of the concerns I had was printing threads on one of the parts, basically I wanted to have the nosecone screw onto the payload section because there isn't enough space for screws.
this is printing at .2mm layer height in PETG. Overall pretty good! Definitely needs some finishing work because I neglected to design in any clearence.
Can you post your flight data and structural analysis? I am using your project for my L1 so it would be nice to have that. I can do the simulations and post my data here if you would like.
Are you having any problems with layer de-lamination with the body tubes? Or maybe you're printing them sideways? We designed and printed an F-class rocket a couple years ago, it worked great, only the tubes would de-laminate often. Eventually that problem, along with excessive weight, led us to print everything but the body tubes. We used thick cardboard, LOC tubes from Apogee for body tubes, and if anything ever happened to the tube we would just cut another, pretty reproducible. Just curious if you found a way around the inherent problems.
Wow - the biggest I ever flew back in the day was a D-class. K seems like a huge leap over that. Which plastic will you print the parts in? How do 3D-printed parts respond to the heat of the exhaust and ejection charge?
A K motor is the ultimate goal, I'm starting with lower impulse motors and working my way up. I'm using PETG for most of the parts, as far as heat I'm going to run tests of the mount to make sure it holds up (it should, but saftey first!)
Can you post your flight data and structural analysis? I am using your project for my L1 so it would be nice to have that. I can do the simulations and post my data here if you would like.