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I've had a 3D printer for years, and have printed nose cones and fins, and even a whole rocket (I'll get back to that in a minute).
The art is knowing when you can print structural things, and when you need to combine them with other materials.
For a small rocket staying subsonic, I have no problems printing nose cones as they don't need to be especially strong. The nose cone and fins on the ACME rocket with the coyote in my avatar is an example. The motor mount and airframe are phenolic, the centering rings are plywood, that's what is taking the thrust. The nose cone has a built-in chamber for nose weight, because short rockets....
I have printed fins with NACA symetrical airfoils for small 38mm airframes that stay subsonic, and fins with symetrical Von Karman profiles that go sonic on a 54mm airfame, but both used a rectangular core of G10 plates using thru the wall mounting. The printed fin is just glued on for aerodynamics, the strength comes from the G10 and phenolic airframe.
I've got a larger project going where I've printed the Van Karman profile fin as a mold to lay down fiberglass, but these fins will also have a plywood core mounted thru the wall to a traditional fiberglass airfame, and held on with dense expanding urethane foam, and will get some tip-to-tip fiberglass reinforcing. These are made to fly with M and N motors, and the plywood core is enough to handle fin flutter. It's not using 3D printing as a structural element, but contributing to the build by making very precise airfoils to mold from. I see that as a possibility for nose cones and transitions as well.
As far as printing an entire rocket, I've come fairly close with an egg shaped rocket based on the mini-nuke from the video game Fallout4. It had a 38mm motor mount just barely visible with a retainer, glued inside to a 98mm phenolic airframe holding the parachute. Used a short 98mm coupler to attach the nose cone (which was weighted, because short rockets....). The entire exterior was 3D printed, including a ring fin. Painted it up to look weathered and rusted, included a faded radioactive symbol. Again, the parts under thrust are traditional, the shell on the outside was printed.
As obsessed as I am about aerodynamics and making things non-traditional in form, I've got a half completed rocket where the exterior is completely a Von Karman profile from the nose, a short straight section in the middle, and continuing as a van Karman profile as transition/tailcone to the motor opening at the bottom. One long needle. At the core is a 54mm motor mount and interior airframe holding the electronics and parachute sections. Around it are very light 3D printed sections. In the upper sections and at the thickest part I used fiberglass rods to stiffen en glue the sections to each other. The exterior will get a few layers of fiberglass, as well as all areas where the sections are glued together, making a sort of bulkhead. The fins will be droopy looking Von Karmen profiles with G10 cores that I've used on other designs. Am experimenting with chrome finishes, but it may just be metallic paint. The business end is made to take on a K/L 54mm motor, and the exterior fiberglassed, but it's basically a 3D printed rocket. I'm convinced it will fly.
Again, the art is knowing when you can print structural things, and when you need to combine them with other materials.
The art is knowing when you can print structural things, and when you need to combine them with other materials.
For a small rocket staying subsonic, I have no problems printing nose cones as they don't need to be especially strong. The nose cone and fins on the ACME rocket with the coyote in my avatar is an example. The motor mount and airframe are phenolic, the centering rings are plywood, that's what is taking the thrust. The nose cone has a built-in chamber for nose weight, because short rockets....
I have printed fins with NACA symetrical airfoils for small 38mm airframes that stay subsonic, and fins with symetrical Von Karman profiles that go sonic on a 54mm airfame, but both used a rectangular core of G10 plates using thru the wall mounting. The printed fin is just glued on for aerodynamics, the strength comes from the G10 and phenolic airframe.
I've got a larger project going where I've printed the Van Karman profile fin as a mold to lay down fiberglass, but these fins will also have a plywood core mounted thru the wall to a traditional fiberglass airfame, and held on with dense expanding urethane foam, and will get some tip-to-tip fiberglass reinforcing. These are made to fly with M and N motors, and the plywood core is enough to handle fin flutter. It's not using 3D printing as a structural element, but contributing to the build by making very precise airfoils to mold from. I see that as a possibility for nose cones and transitions as well.
As far as printing an entire rocket, I've come fairly close with an egg shaped rocket based on the mini-nuke from the video game Fallout4. It had a 38mm motor mount just barely visible with a retainer, glued inside to a 98mm phenolic airframe holding the parachute. Used a short 98mm coupler to attach the nose cone (which was weighted, because short rockets....). The entire exterior was 3D printed, including a ring fin. Painted it up to look weathered and rusted, included a faded radioactive symbol. Again, the parts under thrust are traditional, the shell on the outside was printed.
As obsessed as I am about aerodynamics and making things non-traditional in form, I've got a half completed rocket where the exterior is completely a Von Karman profile from the nose, a short straight section in the middle, and continuing as a van Karman profile as transition/tailcone to the motor opening at the bottom. One long needle. At the core is a 54mm motor mount and interior airframe holding the electronics and parachute sections. Around it are very light 3D printed sections. In the upper sections and at the thickest part I used fiberglass rods to stiffen en glue the sections to each other. The exterior will get a few layers of fiberglass, as well as all areas where the sections are glued together, making a sort of bulkhead. The fins will be droopy looking Von Karmen profiles with G10 cores that I've used on other designs. Am experimenting with chrome finishes, but it may just be metallic paint. The business end is made to take on a K/L 54mm motor, and the exterior fiberglassed, but it's basically a 3D printed rocket. I'm convinced it will fly.
Again, the art is knowing when you can print structural things, and when you need to combine them with other materials.