1:93 Scale Saturn 1B

[LithosphereRocketry]

Seeing how well grandcross and Max Q's Saturn 1B projects are turning out, I thought, "why not try my own?" I started fooling around in OpenRocket and, after a bit of obsessive fiddling, came up with a reasonable design. The exterior (S-IVB) airframe is 3" in diameter, with the capsule and service module lining up nicely as BT-60. The first stage is a 29mm tube with 8 BT-20's clustered around it and will hold a 24mm motor mount. My "BT-60" and "29mm" tubes, as well as my motor mount, are tubes from paper towel rolls, etc. that I happened to have lying around. I haven't put together a paint scheme in OpenRocket yet, but here's a few pictures without it:

The build may take a while to get started because I need to do a bunch of part-gathering... I still need a 3" tube, and I'll be laser-cutting & 3D printing parts next week. I'm leaning towards either the Estes 3" tube or the Apogee thin-wall tube, which are about the same.

The other issue is that I'll be doing a cardstock transition for the petal adapter, which I haven't done before. If anyone has advice on making those, I'd love to hear it!

 

[MaxQ]

Alright !
Bring it on!

 

[LithosphereRocketry]

It might be a bit before the build really gets moving, as I still need a few more tubes...

On the bright side, I'll probably be able to do most of the printing & laser-cutting in the next week or so. Hooray for CNC!

 

[LithosphereRocketry]

I readjusted OpenRocket a bit, and really got the design dialed in. It turns out one of the motors I was simming was a reload, so I re-simmed with a DMS equivalent (24mm motors mean no HAZMAT shipping and (relatively) cheap SU motors) and found that I could dump off about 20g of nose weight, bringing my target capsule weight down to a modest 2.4 oz. I'll attach an updated OR file.

I also prepped the parts I have now. More tubes are on the way.



I wrapped a scrounged 24mm tube in a bit of masking tape & added a section off the end of a motor casing as an engine block...



Motor mount done!



I should be able to get a few rings cut either Monday or Tuesday, and the rest of the tubes will come sometime in the next two weeks.

 

[NJRick]

awesome!

 

[LithosphereRocketry]

Thanks NJRick! Glad to hear the pros like it.

Have you done one of these in this scale before? It works out nicely with 3"/BT-60/29mm/BT-20...

 

[LithosphereRocketry]

ignore

 

[LithosphereRocketry]

Good news- I got all of the rings & fins laser-cut today. Here they are:

Bad news- What I thought was a BT-60 was actually a bit smaller, just enough to be a pain. I have a bunch of BT-60 coming for a different project anyway, so I'll just use that.

I did get a bit of assembly work done, though - I glued some rings onto the 29mm booster stuffer, which will attach it to the BT-60 that eventually forms the service module.


Now I'm just waiting for tubes to get here...

 

[NJRick]

Litho,
you are way beyond my skills...I basically build kits. I look on in amazement as you guys make these beautiful scratch builds. My latest 1b was the Fliskits Saturn 1b...its 9.5" tall...lol

Thanks NJRick! Glad to hear the pros like it.

Have you done one of these in this scale before? It works out nicely with 3"/BT-60/29mm/BT-20...

 

[Bat-mite]

If the rocket is as skillfully rendered as the OpenRocket model, that will be might impressive!

 

[LithosphereRocketry]

Litho,
you are way beyond my skills...I basically build kits. I look on in amazement as you guys make these beautiful scratch builds. My latest 1b was the Fliskits Saturn 1b...its 9.5" tall...lol

If the rocket is as skillfully rendered as the OpenRocket model, that will be might impressive!

Thanks guys! Don't expect too much, though. I'm not all that great at this, and I have a habit of making at least one glaring stupid mistake per build...

 

[grandcross]

Just came across this. Please don't be finished before me given that I've got almost a year head start!

 

[LithosphereRocketry]

I still have some tubes coming in the mail, but after that, all bets are off

Yours is a lot more complex than mine, though... The nice thing about a 2 1/2 foot tall rocket is I don't need carbon-fiber wrapped fins.

 

[grandcross]

The other issue is that I'll be doing a cardstock transition for the petal adapter, which I haven't done before. If anyone has advice on making those, I'd love to hear it!

I needed to wait until I had access to the computer with the right bookmarks, but here you go. A great site with great tips on how to do the scallops is here: https://meatballrocketry.com/saturn-construction-tips/

The other tip I have is to use your 3D printer to make a template. Many people think it's used only for parts, but I've found it quite useful for tooling. Make a cone, put your template over it and cut to shape. Or if you're using the tube cutting method shown on the referenced site, put the template over your tube and cut to shape.

Good luck!

 

[LithosphereRocketry]

Thanks grandcross! I'm doing the cardstock shroud for the upper transition, though, not the booster - I 3D printed that one. In this scale, a honeycombed 3D print isn't much heavier than cardstock and extra centering rings. If I ever make a bigger version, though, I'll keep that advice in mind.

 

[Ez2cDave]

Bad news- What I thought was a BT-60 was actually a bit smaller, just enough to be a pain. I have a bunch of BT-60 coming for a different project anyway, so I'll just use that.

Use a length of BT-60 coupler and build it up to whatever diameter you need !

 

[LithosphereRocketry]

That wouldn't help - the tube I have is smaller than a BT-60, so having an even smaller tube wouldn't help. The issue is with inside diameter.

I already have a 3pk of BT-60 tubes on the way for another build, so I'll have plenty of extra.

Thanks though!

 

[LithosphereRocketry]

The tubes arrived yesterday, right on time!



I started by assembling the stuffer tubes. This way, everything else will go over them as a sort of sleeve.



And centering rings on the upper section...



The capsule was 3D printed using a laser-activated acrylic resin printer, which is very accurate but takes hours to print. After a bit of sanding (and way too much fiddling around in CAD), I ended up with a decent looking capsule:



The windows & such on the capsule are not strictly scale, but I added them anyway just for fun.

The capsule then received about 2oz of weight, in the form of ball bearings layered with clay. This just about filled it to the shock cord eyelet, which is in the wall of the shoulder.



With the rings dry, I was able to get a sense of how big the final model is going to be.



I also got started cutting up the booster tubes. Here I have 4 dry fit into their shroud & upper ring - they actually stay together just by friction.



More to come!

 

[LithosphereRocketry]

I've finally gotten around to posting my recent progress.

I did a whole bunch of tube cutting and ended up with 8 9" sections of BT-20:


Of course, I dry-fit everything just for the fun of it.


The first tube is up... I Duco cemented the tube into the ABS part. I've found that Duco cement will stick to just about anything, if not very strongly. The ring just needs to hold them in place until they get wood glued to the tube.


Tube #2... For ease of alignment I'll be assembling the tubes as a sort of sleeve and then slipping that over the main tube rather than putting little tubes on and following them with a ring or two. The ends were rubber-banded together for alignment.


While trying to glue in the 3rd tube I realized this process would be a whole lot easier if I just added the fore ring now. In retrospect, I couldn't really have done it before then, so I stumbled into a pretty efficient order to build this. The other tubes have been snapping into place without any "interesting" results.

 

[LithosphereRocketry]

I decided to paper the fins on this one, which I don't normally do. I thought they would look a little nicer, as well making me feel better about launching on F21 composite motors.

I came up with what I thought was an OK techinque. First each fin was coated on one side with a thin film of wood glue and glued to a sheet of paper, then clamped down:


Then I ran a Xacto blade around each fin to cut the paper layer away form the sheet:


Another round of gluing and trimming, followed by a bunch of sanding, gave me a set of nicely papered fins.


If anyone else has another technique I'd be happy to hear it - this probably isn't the best way to paper fins, it's just what I came up with on the spur of the moment...

 

[Charles_McG]

TRF'r K'Tesh has a detailed tutorial on his papering method.

 

[LithosphereRocketry]

I got a ton of work on the Saturn 1B done yesterday.

I finally finished the fillets on the booster section. Now the parts are ready for final assembly! :w:


The booster section was glued over the 29mm tube with only minor elbow grease, then a centering ring was added to the end:


I realized that the top ring of the booster section wasn't quite in the right place... It's not a huge deal, I just slid the tube over it. That was followed by a short section of tube at the tail:



After that I set about printing the cardstock transition. When I printed it on normal paper, it fit perfectly, the cardstock version ended up about 1/4" short of reaching all the way around. My guess is the printer couldn't feed it as fast as it thought it was, so the image ended up distorted ever so slightly... :eyeroll: Tracing the normal paper version onto cardstock worked fine. I also built in some tabs on the top & bottom to help the cardstock adhere to the tube... I'm not sure how necessary this is, but I decided to just play it safe.


The transition glued on with relative ease... However, I didn't like the look of all the little tabs, so I decided to glue a paper wrap over them. However, I've used my allotted 10 pictures, so that'll have to wait until my next post...

 

[Charles_McG]

I find that I have to print cardstock 1-2% bigger than plain paper to get transitions to fit right.

At some level it makes sense - thicker paper means larger radius. I don't know that the math works with the empirical adjustment, though.

 

[LithosphereRocketry]

I find that I have to print cardstock 1-2% bigger than plain paper to get transitions to fit right.

At some level it makes sense - thicker paper means larger radius. I don't know that the math works with the empirical adjustment, though.

I don't think that was the problem - even laid flat, the cardstock and paper versions were noticeably different, and the circumference distance was a lot farther off than one would expect from just the thickness of the paper. Tracing around the paper, like I did for my final version, does add a tiny bit of width though, which might be closer to a sheet-of-cardstock order of magnitude...

 

[LithosphereRocketry]

I don't have time to document all of my recent building work just at the moment, but I can at least show the wraps.

I'm wrapping the SM & upper tube in plain paper just for appearance's sake. No fancy prints, just plain white paper...

The SM wrap worked fine, but the upper tube one wrinkled up a ton. Since then it flattened out a bit, but still not incredible.

Because I was basically doing these with scrap paper, I decided to only do the larger one down to where the interstage corrugations would be on the real thing, about 2/3 of the way down.


I was a bit worried about the edges of the wraps peeling up all the time. So once both wraps were on, I smeared some glue around the seams using the sophisticated method of "dip finger in glue, wipe onto rocket". You can clearly see the seams in the pic:

I don't have space to upload all my pics in this post, but I have one more thing to add: I finally got a decent rendering in OR together...

 

[LithosphereRocketry]

I found some time to sort through my backlog of build pics... Here goes.

Some lines were marked on the bottom ring, along with one all the way up for the launch lug... And the fin-attaching process begins!

My fin technique was a little weird to account for the plastic transition. I woud smear the "flat" root with wood glue and the "angled" one with Duco cement. It seemed to turn out pretty well.


I was debating which, if any surface features to add. I settled on doing the one main wire conduit on the S-IVB (upper) stage and not much else. I'm just not that picky about everything being perfectly to scale, and the other parts are really just too small to bother with for me at this level of detail.

Anyway, I made it out of a bit of scrap wood and glued it on, along with a few more fins...


Aaaaand the unpainted assembly is, more or less, done!

 

[LithosphereRocketry]

So, despite my best efforts with my other two current projects, I couldn't distract myself from doing the first coat of paint...

The capsule came out good, but the booster fuzzed in several places. The paint I use does fine without a primer, so I don't use one and use white as my "primer". Feel free to yell at me.

 

[LithosphereRocketry]

First, a bit of easy stuff: the SM was painted. The silver paint wrinkled up like crazy and pulled up the white, so I just wiped the whole thing off with a rag and re-painted. It came out fine. Yes, I know, I didn't use primer, but I've used these exact paints before and never had a wrinkle.


Now for the hard part. Masking for the roll pattern.

This was... interesting.

Most of the pattern is fairly straightforward, like the simple stripes on the upper half. Not so much with the booster. The tubes themselves weren't bad - I just used a strip of tape with a pleat to take up the extra width. The hard part was the scalloped transition from the booster tubes to the bottom ring. I came up with what seemed to be a decent method: First, I would stick a big piece of tape over the area to be masked. Then I would run a razor blade around the seam a few times to cut through the various layers of tape and attempt to pull off one side. More often than not, though, I'd only get the top layer, so I'd do another round of razoring.


I slapped a coat of white on top to seal it, but I don't have a picture of it as a) it's not that interesting b) my camera has about 5 pictures of space left on its card.

 

[LithosphereRocketry]

Aaaaand... the rocket is just about done!

It's about the size of an Estes Interceptor, but much heavier. (Yes, my Interceptor has blue pods. What a rebel.)


My masking job worked pretty well, with just a few minor runs. However, it seems I entirely forgot one side of one of the fins when I was masking. That will probably get a bit of white label paper at some point, but it looks OK for now.


I couldn't resist... All it needs now is a launch tower...

 

[Bat-mite]

Go get 'em! Nice work.