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

The Rocketry Forum

Help Support The Rocketry Forum:

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
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

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
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

Well-Known Member
Joined
Jan 21, 2009
Messages
700
Reaction score
260
Cool project! Two layers of glass is usually the most you need, any more is really extra weight with diminishing benefit.
 

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
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.
 

drewnickel

Active Member
Joined
Apr 2, 2018
Messages
34
Reaction score
15
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.
I flew an M1491 with fly away guides. I recommend getting additive aerospace rail guides and replacing the aluminum rods with carbon fiber tubing.
 

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
I ordered a set from AM and it came with carbon rods, so I think I'm good to go. Thanks!!
 

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
Bunch of updates on this one... Going to fly it at Midwest Power on Halloween weekend. Just clicked print on the fin can. More updates coming later, but this is going to happen.
 

Buckeye

Well-Known Member
TRF Supporter
Joined
Sep 6, 2009
Messages
2,833
Reaction score
608
 

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306

Lol, thanks for the vote of confidence.

I'm planning on touching Mach 1.3 for a second. Not worried about aero heating.
 

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
I'm going to read your thread and reply... I'm a Materials Engineer, I have thoughts on your flight, will get to that when I can stop and think a bit about it and put words to the thoughts.
 

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
Looking at Buckeye's thread, my flight here isn't that ambitious...sims say 12k feet and mach 1.3. Looks to me like that was aero heating, and this will a) barely be above mach and b) not for very long. Not worried about that aspect of it.

Updates here:

Printing the fincan over the next 4 days. This is the fincan itself. Tried to radius everything I can, the fins are 10mm wide at the bottom and 3.5mm at the tip. 8 holes in the bottom for thermal inserts to hold the tailcone on:

Fincan.PNG


It's going to use a tailcone that grabs the thrust ring on the back of the motor for motor retention. The fincan will be secured to the lower tube with 4 screws, but I'm also going to put a ring on the outside of the tube, so the fincan can push on that as well.

Assem.PNG


This is what the sliced file looks like:
Slice 1.PNG



And what the inside looks like...going with 8 solid layers all around, 90% infill in the few places where there is actually infill (the orange on the sectioned view). 1350 grams w/o support being considered. I have a fresh spool of PETG fully dehydrated and then being run out of a cheapo SunLu thing to keep it dry, with another spool drying in the dehydrator right now. Guessing I'll need to switch over about Friday morning.
 

Attachments

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
wow, 76hrs!

Nice to see someone else using Simplify3D!
It was 120 hours until I switched from a 0.4 to a 0.5 nozzle and bumped the layer height! My record on the 0.4 nozzle was 170 hours or something like that. More than a week.

S3D is what I started with, and I have it dialed in on my computer at home, but at work I've just started dabbling in Cura...holy crap there is a ton of possibilities there. I'm probably going to switch at some point, unless S3D *finally* releases version 5. It's been "about to release" for 4 years now. I love the interface and speed of slicing in S3D regardless.
 

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
Been doing design work on the nose cone - my initial idea for the GPS tracker (Eggtimer) had been to put the transmitter inside the nosecone. Based on some limitations with my printer, I'm thinking that's gonna be hard to do and I'm thinking about basically making a container for it housing the transmitter, battery, and whatnot and just attach that to the main parachute shock cord. Does that make sense? It would simplify things a ton on the nosecone side of things.
 

robopup

New Member
Joined
Oct 8, 2021
Messages
1
Reaction score
0
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
Been a couple weeks, so I suppose the print either was successful or failed by now. W/r/t falling over, using PLA I regularly had issues with this until I started adding a "Brim" on the first layer (I use Slic3r). Haven't had an issue since.
1633659569831.png
 

Dustin Lobner

Well-Known Member
TRF Supporter
Joined
Sep 3, 2019
Messages
475
Reaction score
306
Been a couple weeks, so I suppose the print either was successful or failed by now. W/r/t falling over, using PLA I regularly had issues with this until I started adding a "Brim" on the first layer (I use Slic3r). Haven't had an issue since.
View attachment 484810

Yeah, Print was mostly a success...the filament slowly rehydrated during the print, so it came out good and then got worse towards the end (the bottom of the rocket, same orientation that you have there). I printed a crapton of things for it...will upload updates at some point, things came out pretty dang awesome.

I got another 3KG roll set up tonight to reprint the fincan, but it's still bubbling coming out, so I'm going to let it dry for another day.

The big key was to modify my dehydrator. I put a turning table/bearing thing in the bottom, ziptied to the shelf in the dehydrator...then drilled a hole out the side and put a piece of bowden tube through the wall, and now I can print direct from the dehydrator. Works great once the filament is actually dry.
 
Top