1/84 scale Artemis 1 SLS LONG haul project

[novahobbies]

Well, I think its time I admit my super-crazy project. Most of the tubes have come in, and at least the test parts have been printed. A few items will be re-printed as i go along and make changes, but I was able to stack some things together just to get a rough idea of how everything will look. Please disregard the transition shroud of the Saturn-V here, it's merely a placeholder for the moment. The main body is the 4" Estes Saturn V tube. Upper tube holding the capsule is a BTH-70 (which I will need to thicken slightly; I'm thinking 16th inch foam sheet), and the srbs are semrock LT-175 tubes. I will need to extend the body by about 3 inches before starting the transition shroud, and cut down the SRBs by about a half inch. It's going to be a VERY long build and we're barely in the baby stages, but here we are. Current plans for this will be for a three-engine rocket with 24mm D engines in the SRBs and possibly a 29mm F in the core. That might change. I haven't completely given up the idea of making the core with a quad of C level 18mm motors thru the actual nozzles. But here is the layout of the parts, just to give you an extremely rough idea:

 

[Charles_McG]

Are the STLs available?

 

[novahobbies]

Are the STLs available?

There are STLs of the whole SLS freely available on Thingiverse. I picked one I liked, started chopping it, sized the parts appropriately, and began modifying it by adding the shoulders to the nose bits and bottom cans. So.....I suppose the answer is "no," there aren't any easy parts freely available. But when I'm finished I will upload my final parts to thingi with a breakdown of the tubes needed. I may not even use this current file. I'm a little disappointed in its low poly nature. But it will absolutely work well enough to get the project moving.

 

[Charles_McG]

Just checking. I have modded thingiverse files before, also.

 

[rcktnut]

Looking good so far, I just hope yours gets off the ground!!!

 

[Hobie1dog]

nice printed parts

 

[novahobbies]

Looking good so far, I just hope yours gets off the ground!!!

I can 100% promise you it will go up, and come down.
The manner in which that happens remains to be seen.

 

[novahobbies]

Old school centering ring building today

 

[novahobbies]

The walls for the transition were cut from some spare tubing I had left over from my Saturn V build. I had to order a new tube for that one (shipping wad terrible to that model and the BT was heavily damaged) but I kept the damaged tube and now it's being put to good use.
View attachment 20220917_194550.mp4

 

[novahobbies]

Still cutting out centering rings. Today it's the motor mounts. I went with quarter inch ply, because... because all the hobby shop had was 1/4" ply or 1/8 basswood! The basswood was fine for the upper half of the rocket with the transition, but I wouldn't have trusted it with the motor mounts. I guess it's about time to order the rest of the parts for the mounts, and start working on those SRB separation points.

 

[JRL303]

How about a G64 for the core?

 

[novahobbies]

How about a G64 for the core?

Probably going to start with something smaller to begin with, but nothing is off the table. I WOULD like the core stage to burn longer than the SRBs, but I haven't decided if I should mount snap-on fins to the core. Each SRB will have 2 fins (but I'm going to install 4 mounts on each SRB in case I get silly and decide to just fly an SRB alone)

 

[Raptor 2]

The walls for the transition were cut from some spare tubing I had left over from my Saturn V build. I had to order a new tube for that one (shipping wad terrible to that model and the BT was heavily damaged) but I kept the damaged tube and now it's being put to good use.
View attachment 538053

Recycle Reuse Check Beautiful job so far!!!

 

[novahobbies]

While I'm not trying to rush this, I am sort of happy to report that it's moving forward a bit faster than I thought. I got the rest of the motor mount hardware ordered today, along with the booster clips from Apogee for the SRBs. And I sorted out the problem I was having with my shroud calculator and got a few options printed on card stock at work today, so I may be able to get the upper stage of the core cleaned up a lot more tonight. Now I just need to sort out the mounts for the "snap-on" fins I'll be using for the boosters.
At the moment I'm thinking only the boosters will need guidance fins. but part of me is wondering if I shouldn't add similar fins to the core as well. They'd be clear lexan so not terribly obvious. I doubt I'd ever try to launch the core by itself, but it might make the center stage more stable after the SRB sep? I'm just not sure.

 

[Raptor 2]

Booster clips? I’ll have to look those up to see what they are used for. I’m assuming you are mounting engines in the sustainer and each of the SRBs. you’ll have 3 separate items coming down on chutes? Do the SRBs separate at apogee, if so stability on the sustainer wouldn’t be an issue so you wouldn’t need fins on it as the chutes would becoming out.
Definitely a more complex model than the one I’m considering building. Will be watching with interest the progress on this one.

 

[novahobbies]

Booster clips? I’ll have to look those up to see what they are used for. I’m assuming you are mounting engines in the sustainer and each of the SRBs. you’ll have 3 separate items coming down on chutes? Do the SRBs separate at apogee, if so stability on the sustainer wouldn’t be an issue so you wouldn’t need fins on it as the chutes would becoming out.
Definitely a more complex model than the one I’m considering building. Will be watching with interest the progress on this one.

It will come down in 4 parts, not three. The center core is being designed very much like the Estes Saturn V, so each half will have its own chute when the ejection charge pops. And yes, the boosters will come down under simple 12" chutes.
Fair warning, I'm designing this by the seat of my pants. Others will probably do similar projects, only more well thought-out, in the future.
Since I have a different and larger motor in the core stage (E16 min) compared to the 24mm motors in the SRBs, I don't think the core will be completely done when the SRBs pop their tops. With that in mind.....it might behoove me to put some small clear fins for the center as well. I don't think there's MUCH difference between the timing of each, but.....better safe than sorry.

 

[novahobbies]

Not much to show for tonight, but it was still good progress. Transition cone cut, test fit, and now clamped and glued. The BT it's going around needed 5mm of thickening, which I accomplished with adhesive-backed foam sheet. It says it's 2.5mm thick but it's really just 2mm. I'll suffer the loss of 1mm just to move the project forward. If I'm very impatient I may get the transition cone glued in tonight. More likely that will be a tomorrow problem.

 

[novahobbies]

The glue was dry enough for a test fit. I checked the size, snapped this photo, then re-clamped the seam to dry fully overnight.
But darn it's starting to look like the SLS. That correct sized transition makes a huge difference.

 

[Raptor 2]

Wow that is some big rocket. Does the ejection charge in the SRBs separate the booster from the center core and also eject the chute? Looking at the Apogee site the booster clips are designed to allow separation. Don’t quite understand how the force of liftoff doesn’t separate the booster from the core.

 

[novahobbies]

I have been enjoying other builds and procrastinating on this one. But I got a little done tonight. Glued down most of the O-rings and also added the guides for the lock-in fins on the SRBs. Got more O-rings to do but it's coming along.



Going to try and keep up the momentum tomorrow night as well. Might be able to finish those rings and maybe get the SRB's 24mm motor mounts done.

 

[Raptor 2]

Nice job on the O-rings. Interested in what these lock in fins look like and how they will lock into the guides.
An impressive model. It’s going to be a heavy weight!

 

[novahobbies]

Nice job on the O-rings. Interested in what these lock in fins look like and how they will lock into the guides.
An impressive model. It’s going to be a heavy weight!

I haven't designed the shape of the fins yet but they'll be cut out of eighth inch plexi and then have a 3/16 flange at the base that will slide down into the 3d printed guides. They won't fall out because the guides have a stepped top that locks them in place, and I'll keep them from sliding back UP (during ejection charge, etc) with the high tech application of a rubber band locking the top of the fin in place. We'll see how it goes.

 

[Raptor 2]

1/8” plexi. Sounds like a lot more weight being added. Are you still thinking of adding fins to the center core?

 

[novahobbies]

1/8” plexi. Sounds like a lot more weight being added. Are you still thinking of adding fins to the center core?

Mmmmm, maybe 16th plexi will work fine. I'll check when I get to HD tonight.
As for the center core, no, I think we're going finless there. At least for the first flight. Might be the only flight. Either way it will be interesting.

Actually, the more I think on it, the more I feel like I should be adding at least SOME finnage to the core. Even if they're small.

 

[Raptor 2]

Anything could happen with the stability of the center core when the ejection charges go off in the SRBs and their separation. Slight differences in their discharges could send it off on an angle.

 

[novahobbies]

I don't WANT to add fins to the core, but what I want and what's best for the rocket may diverge significantly here. I'll attack that problem after the SRBs are done and the mounting brackets for the core are finished. To be fair, I'll mark lines for 4 clear fins just to be safe.
I was looking at burn times for motors this morning. D12-0 or D12-3 motors for the SRBs have a 1.7s burn time, so the core here should probably be a E16.4 at 2.1s burn time. Alternately I could go with more power and use E12-0 or E12-4 for the SRBs (2.4s burn) and an F15-4 for the core (3.5s burn time)

 

[novahobbies]

Starting to pass into points of no return now! SRB motor mounts glued in. Resin shrouds still not glued (may reprint first.)




Didn't make it to HD tonight for the fin material. So this got done instead. Think I'm going to start tackling the booster mounting hardware soon!

 

[novahobbies]

Well, got the SRB fins cut. Waiting on the 8th inch acrylic that will be used for the fin root. Was supposed to be delivered today, but as per usual Amazon attempted delivery to my 9-5 business address at 7:45pm (despite delivery instructions) and maybe I'll get it tomorrow.
But that's okay! Because fins! These are just balanced in the fin clips here:


Now for the bummer news. The more I think on it, the more I'm sure I should put clip-on fins on the core, too. Sorta stinks because I wanted the core to be as close to the real thing as possible, but....better safe than sorry. I'd like this rocket to stay under power after the SRBs are gone, and the only way to do that will be using fins on the core. So that's pretty much that. It'll still look cool.

 

[novahobbies]

Not pictured but done: the balsa rails that the booster hooks slide into have been glued onto the SRBs. That'll have to do for tonight.

 

[Raptor 2]

Can you take some closeup shots of the balsa rails and booster hooks? Not quite understanding the operation of these.