Saturn 1B - 1/23 Upscale

Spent an evening looking at the LES tower and then proceeded to do a couple of things.
Cut the tower body tube to length and fiberglassed that with two layers of what I had on hand.
Trial fitted a mylar LES skirt and shroud for the nose cone.
The skirt was fairly easy, the online shroud template calculator actually gave a pretty good result for that .
After getting a good trial fit I unfolded it, took a compass and marked a .10 inch radius inset and set a balsa bulkhead/cross grained doubler inside that.
That will be the floor of the LES skirt .
After fiberglass reinforcement - I'll drill some holes for the LES tower struts.
The nose cone took a lot of trial and error cutting and re-cutting but eventually I got a mylar NC shroud that I could use - so I inserted a wood dowel inside and shaped the NC tip.
Some filler and sanding...think I can fiberglass both of these parts this week end.
The red thing near the LES -NC is a tube coupler, which got stuck in the BT and seems to want to stay there.
I'll probably have to reverse the BT , stick that end in the skirt.
I want to be able to load lead ballast in this LES so the NC won't be getting attached anytime soon.

Prepared several layups of FG for the CM shroud, trimmed off the excess.
Nice and solid after curing.
CM assembly will need an internal body tube/central core part and a base.

Got a scrap piece of pink foam, cut out a base for the CM, then took a 3.9 Inch radius to allow a central tube coupler to inset into the base and attach capsule parts.

Test fit looks ok, will probably need cosmetic trim parts for the exterior and a band along the base to extend the CM blast cover to.

Did some work on the CM capsule - forward cone part, and trial fit to the SM. then ...made a shroud template for the capsule blast shield cover and FG'd the forward blast shield cover topped with a small wood nose cone.

Had to number and mark the individual tower legs as they each vary slightly, so after FGlassing the blast cover, I'll need to refit them to pre marked locations to permanently attach them thru the blast cover.

Worked on the Command module and LES tower this evening.

After making registration marks for the tower on the CM blast cover and LES skirt - I drilled holes for the tower legs.
Was worried that the assembly would go together and be plumb...appears to have worked out ok.

Cut out LES nozzle shrouds from card stock and will and fiber glass those, so after they cure I'll probably move on to the overall airframe.
Fin can ring and fins. That will be a challenge.

Man that is going to be a beauty. Keep up the good work Max Q.


Alexander Solis - TRA Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

SinfulDarkLord said:

Man that is going to be a beauty. Keep up the good work Max Q.
Alexander Solis - TRA Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

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Thanks Alexander...I've been trying to keep up the progress on this build, and if I do something every day, even if small, it will get done.

Scratch building is a challenge, doing a scratch built scale model is more so, and building a -big- scratch built scale model, even more so.

No instructions to look at when you get to a stopping point, only your past experiences of previous builds in your head, and whatever observations of others projects you can recall.
I recommend it.

Not looking forward to all the exterior details on the airframe though...all those vertical ribs/detailing, - or the internal electronics bay work.
Still working that one out, but has to be finalized before the airframe gets completed.

But when it starts looking like a scale model it starts getting exciting.

Cut the LES escape tower nozzles shrouds from mylar to match the previous card stock shrouds, then did FG wraps.
Trial fitting to ensure they fit in the spaces between the tower structural part looks ok.

This is going to be so badass!!

marcusSRG said:

This is going to be so badass!!

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Thanks...I hope so.

MaxQ said:

Thanks...I hope so.

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No its you know so


Alexander Solis - TRA Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

SinfulDarkLord said:

No its you know so
Alexander Solis - TRA Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet

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:wink:

she is looking awesome so far!!!

This model is looking very good. Obviously, you have no qualms about working with fiberglass.

Thanks Guys.
Any recommendations of where the electronics might go?

MaxQ said:

Thanks Guys.
Any recommendations of where the electronics might go?

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I've been giving this some thought. Here's my summary of the problem:
1. Electronics in both the upper and lower stage
2. Minimize impact on the look of the rocket
3. Maximize accessibility

For this I recommend taking advantage of the large inner space between the interstage and second stage regions, and the internal airframe.



You're probably going to need something similar to an ebay in the internal airframe, if for no other reason than to make loading your ejection charges simple. There's no need to put the electronics in there though. They can be in the space outside of the internal airframe. The airstart electronics and battery can fit inside the tanks - that's just unused space. For the switches, magnetic is always an option as the don't require external access. Or you can do as I've outlined in the diagram, where you access both the upper and lower electronics through the small access panel on the interstage between points I and II. Here the lower stage switches are located on the lower airframe, with the upper switches on a bracket attached to the upper airframe. That access hatch is less than 2 inches at this scale, so it's small but doable.

On a related note, having just completed my Level 3, I was at a loss for my next project. This thread inspired me and I've been watching with great interest. I'm going to start a similar build starting from the same point. I already have the 3" mailers and the large sonatube. I'll be doing some things differently though, such as fiberglass instead of CF for the upper airframe as my electronics has telemetry (Altus Metrum TeleMetrum), and I'll be using my 3D printer for things such as the SM mandrel and various detail pieces.

Love the thread, and I miss it when there's no new posts

grandcross said:

I've been giving this some thought. Here's my summary of the problem:
1. Electronics in both the upper and lower stage
2. Minimize impact on the look of the rocket
3. Maximize accessibility

For this I recommend taking advantage of the large inner space between the interstage and second stage regions, and the internal airframe.

View attachment 298184

You're probably going to need something similar to an ebay in the internal airframe, if for no other reason than to make loading your ejection charges simple. There's no need to put the electronics in there though. They can be in the space outside of the internal airframe. The airstart electronics and battery can fit inside the tanks - that's just unused space. For the switches, magnetic is always an option as the don't require external access. Or you can do as I've outlined in the diagram, where you access both the upper and lower electronics through the small access panel on the interstage between points I and II. Here the lower stage switches are located on the lower airframe, with the upper switches on a bracket attached to the upper airframe. That access hatch is less than 2 inches at this scale, so it's small but doable.

On a related note, having just completed my Level 3, I was at a loss for my next project. This thread inspired me and I've been watching with great interest. I'm going to start a similar build starting from the same point. I already have the 3" mailers and the large sonatube. I'll be doing some things differently though, such as fiberglass instead of CF for the upper airframe as my electronics has telemetry (Altus Metrum TeleMetrum), and I'll be using my 3D printer for things such as the SM mandrel and various detail pieces.

Love the thread, and I miss it when there's no new posts

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Hey Thanks David.
I'll take a close look at the suggestions.

(and if you come up with any good ideas as you get into your build, I'd be happy to steal - oops - I mean try them out :smile: Keep us posted! )

Schematic makes a lot of sense, the components appear well organized around the break line between the upper part (main airframe) and the lower part (tube tank/fin can).

I like the access panel/hatch location - the schematic appears to show a common access to both the upper and lower electronics switches. I dread cutting through the CF main airframe to make a hatch, maybe this can be set up to cut through only a band around the lower tube tank /fin can component and coupler.

I currently have several choices for accelerometer based airstart electronics which have batteries on board - a well used GWiz (that has done airstarts and staging on my two stage Aerobee Hi, and airstarts on my large Little Joe II), a newer less used GWiz deluxe, and a Xavien FIST.

All would fit easily into the lower fin can component, and loading them in the tops of any of the four unused 3" dia. tank tubes makes sense .....they would not need to be vented if used only for air starting, and wiring conduit down the tank tube to the other four outboard motor aft ends should be easy.
I need to keep the front ends of the four of the 3" dia. tubes with outboard motors clear and open - as they augment the central core motor mount for motor based back up ejection for the DD drogue.

I planned on having dual barometric altimeters in the main airframe to handle main parachute deployment as shown in the schematic (Electronics Sled 1 and 2).
Locations shown could be workable...and accessible.

The internal location presents the minor challenge of how to vent them through the CF airframe. More significant would be how/where to load the ejection charges conveniently inside the internal extended core tube which houses the main recovery parachute.
Seems it has to come in through the side, since the butt end of the core tube pf the main airframe has to be open to slide easily over the forward extended core tube of the lower tube tank/fin can.

Other work-arounds to locate in the internal spaces of the main airframe are:
- load bearing hard points on core tube of the lower and upper components for the recovery harness
- storage space for the drogue recovery harness with unobstructed deployment
- internal reinforcement for the hard points on the upper and lower airframe for the rail guide buttons (upper rail guide will need a stand off to align with the wider lower fin can ring)


View attachment 298246

Well, you're going to have to vent and yes that means cutting into your CF airframe. There are a few options which can minimize the impact on the scale look of the rocket.

One is to vent through the nozzle of the ullage motors. They seem to have an approximately 8" diameter opening, which at 1/23 scale is 0.35". But they're in the S-IVB stage just forward of where your coupler would be, so that may entail some fancy plumbing tricks, or creating a hole through the coupler that needs to be aligned. You may be able to do something similar at the base of the retro rockets which are on the interstage, but that would impact the scale look.

There are also the photo targets on the interstage that would be about the right size, and there are 8 of them, but that would mean sacrificing a cool detail, at least for some of them.

The last option I see is drilling some holes in the bulkhead where the tanks meet the interstage. This would have a minimal impact on the scale look, but I'm not sure what the impact would be of having them in what might be in a low pressure airflow area.

Personally I'm liking the ullage motor idea.

At the risk of being Captain Obvious, you'll also have to put some pressure relief in the internal airframe to prevent premature separation, so don't forget that.

As for the ejection charges, I'm still thinking on that. Right now the obvious solution is to use the equivalent of an ebay just to hold the canisters on each end, but that has structural implications as well.

Oh, and while I think about it, download these diagrams. They have great detail information on things like access hatches. I downloaded the larger version, and split it into individual pages to make them usable. Also check out the rest of the site - there's a wealth of information in there!

https://heroicrelics.org/info/saturn-i-and-ib/as-207-drawings.html

So here's the next complication. I was using the vent hole size calculator here: https://www.vernk.com/AltimeterPortSizing.htm

Using the ullage motors for vents, with an 11.5" ID, the altimeter compartment has a maximum length of 6". This ignores the lost volume of the inner airframe, but you get the point. There will have to be bulkheads to restrict the compartment size. Need to rethink this a little...

Hey, if it were easy they wouldn't call it rocket science!

Also for me, I'm not using the motors for back up ejection. I'll be using redundant electronics and dual BP canisters. This will allow me to fly with a 75mm motor on days when I don't want to bother with clustering.

hope this is OK...but I thought I would share some pictures of SA-205...the Apollo 7 Saturn 1b...these pics are from retro space images https://www.retrospaceimages.com/....great resource for builders. I wasn't sure what version you were intending to build but I figured Wally Schirra's booster as pretty as any!

couple more

Keep putting up pictures, I need all the motivation I can get.
...got to keep my energy level up, as the difficult parts of this build are coming up.

I've been looking at the fin can ring and eight fin root attachment points before I assemble the tank tubes in the lower airframe...everything has to make room and give clearance for other components during construction and it does get tight inside the ring, a lot going on in this area.

I've done a template for the upsized fin profile (based on the Semroc kit fins).
I've used the fin template to draw up a dimensioned schematic of both the side view and a plan view of the fin can ring - to size the fin brackets appropriately.

I'd rather not cut eight vertical slots into the CF fin can ring for each fin...it will be a nasty chore and probably weaken the ring.

I've decided to simply drill a hole into the fin can ring at each fin root location...and have a rod attached to the central core motor tube.
Maybe CF rods if hefty enough.
Fins would be constructed with a hole in each, to attach to that.
Looks like the upscale fin profile will hang below the bottom of the fin can ring - which I did not want to have happen.
Landing impact doesn't do low hanging fins any good...

Either the fin profile stays true scale, or I should have made the fin can ring taller in height to accommodate and protect the longer fin.
Or perhaps I can add some scale looking engine bells below the fin can ring to help to take the hit.
- I'll have to think on that one.

Otherwise, I can proceed with assembling the tube tanks on the spacers and tank struts, now that the fin bracket location is determined.

MaxQ said:

Either the fin profile stays true scale, or I should have made the fin can rind taller in height to accommodate the longer fin.
Or perhaps I can add some scale looking engine bells below the fin can ring to help to take the hit.
- I'll have to think on that.

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That shouldn't happen. It's likely the model you used as the base enlarged the fins for stability. I found this dimensioned drawing if you want to double check.

grandcross said:

That shouldn't happen. It's likely the model you used as the base enlarged the fins for stability. I found this dimensioned drawing if you want to double check.
View attachment 298487

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The Semroc Saturn1B kit fins were upsized, if I recall George's earlier postings correctly.

I'll probably go with it, the trade off for smaller scale like fins would probably be moving the CG forward with the attendant weight penalty.

Took a two month break to get back into RC flying while the flying season is active...(got to keep those thumbs in practice for the next two projects, but that's another story).
Unfortunately one of our RC clubs lost their field this season to development, and we had to pull together find another replacement field and move all the structures, sheds to the new site and grade and grass the new field - but that's another story as well.

Upside is, this break allowed me some time to think some things over on this build before proceeeding, and also watch grandcross (Dave) proceed on his Saturn 1B project, and steal some of his better ideas. :lol:
He's moving along, and I'll be tackling that dreaded fin can ring and fins myself soon.

Anyway, after struggling with the main airframe shroud template to fabricate the part that will connect the service module/command module to the main airframe, I finished the internal bracing, test fit the mylar transition template over the internal transition bracing, made registration marks for the overall length, and proceeded to cut fiberglass.

Did the first heavy FG layup ont the transition, test fit that on the CF main airframe - with the excess length at the bottom - marked that, and did the second FG veil lay up last night.

MaxQ said:

,,, also watch grandcross (Dave) proceed on his Saturn 1B project, and steal some of his better ideas. :lol:

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I have good ideas? Who knew?

You'll never catch me sucka! (At least not until the month and a half I spend in Asia)

Seriously glad to see you back. I've missed your updates.

Glad to see your back, I was getting worried. Awesome work on that transition. Keep it up man.


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