Admittedly I was inspired by Andrew Waddell’s big Saturn V construction article. While the Saturn V is impressive, I am much more interested in the smaller Saturn 1b. In the past both Estes and Centuri kitted model rocket versions of this NASA launcher.

Of the two the Centuri version was much easier to build and fly. Estes had re-issued Centuri’s 1/100 version of the Saturn 1b in 1992 but it since has gone out of production. These two past versions were to be the basis for my upscale project.

One of the most troubling features in doing this model is the first stage booster tank tubes. There are very few commercially available body tubes that are sized correctly to evenly space and get a proper circumference for the fist stage booster. I researched and listed all commercially available body tube diameters then sat down at the UniGraphics terminal and built some CAD models.

I eventually found out that a 2x upscale of the 1/100 Estes kit would fit what was available without having to resort to custom ordering. I ended up using Estes BT-56 body tubes for the first stage tanks surrounding a 54mm core tube. The second stage or more correctly the SIV-B stage would be a LOC 5.68" diameter body tube cut down to 4.75" (ala Andrew’s method for the Saturn V) The base of the first stage would be the stock diameter 5.68" body tube.

The hard part was now out of the way. I downloaded the plans for Estes’s 1/70 version of the Saturn from JimZ’s web site. These plans were invaluable for making the command module capsule, LES (launch escape tower) and the fin assemblies. I plotted the shroud for the LEM on the UG and printed it out full size. The pattern was transferred to poster board and cut out. All of the parts I used to construct the Saturn 1b are available through any supplier of high power and model rocket components. (I ordered everything through Magnum)

The kit was constructed very similarly to the Centuri/Estes version where by the rocket is built up and painted in various sub-assemblies then final assembled, detailed and applied decals. I will list each major component and the build process I used.

For me this was probably the second most complicated item to do. If you notice on the Saturn 1b there is a shroud ring on the lower section of the first stage booster that surrounds the first stage fuel tanks. This shroud has scalloped cut outs to accommodate the booster tanks. I used the pattern from the Estes 1/70 plans and enlarged it to the size I thought I would need. I then made a poster board pattern and tried it out. It didn’t work too well. The reason was the lower body tube of the first stage booster needed to be smaller in diameter than the 5.68" one I was using. Since I didn’t want to cut this tube down and make more centering rings I needed to use something else. I finally hit on using thin 1/64" veneer ply. I cut out a single section needed to fair to the booster tank. I then split this in half, made a mirror pattern then glued a rib to the backside that would set the proper angle and setback from the core tube to the edge of the lower body tube. What I had now was one section of lower fairing that would go around one half of a booster tank tube on either side. Now I had to make eight of these.

Veneer ply is very easy to work with and cut. You can use scissors or score with a knife and break it similar to sheet styrene. It is available at most hobby stores. A little pricey though for a sheet since it is so thin. I made my eight sections one at a time. First I cut the lower body tube to the right length, glued in the centering rings and marked out my eight equal sections. Then I started gluing the fairing pieces down using CA. I had little short sections of BT-56 left over from cutting the booster tubes to length and used these for spacing and fit checks. I did each section one at a time checking the fit and trimming where necessary. The total job took about two nights to do. But it was well worth it.

After the unit was filled and sanded I glassed it using ¾ oz glass cloth and epoxy finishing resin. The weave was then filled and sanded smooth.

Main Body Tube:

Next up was the main body tube. This started out as a 5.68" diameter LOC payload section. It was cut to length then run on a table saw lengthwise to remove enough material to reduce the diameter to 4.75" I saved the section I removed to use as a joiner later. To get the tube to hold a circular shape I took the LOC 5.68/54mm centering rings and cut the diameter down to 4.75" I did this by taping the rings together, marking the new circumference and trimming them on the bandsaw. These centering rings were what was used to keep circularity and diameter on the tube. The centering rings were inserted and the splice was epoxied in place with 30-minute epoxy then taped and left to dry. After the splice joint cured the centering rings were glued in place with 30-minute epoxy. There ended up being a gap between sides of the longitudinal cut in the tube. I filled this with scrap balsa and sanded it smooth. I then marked the upper end of the tube to trim off about a 1" section to be used as the base for the LEM Shroud/Command Module Stack.

Now it was time to apply the body wraps. I wanted to have the body corrugations on my model just like the full size Saturn 1b. I used Evergreen Styrene sheets with .10" ribbed spacing on them. These can be found in most hobby shops that sell model railroad supplies. There are many different sizes and styles.

The sheets I bought were 6"x12" and come three to a pack. I used 3 packs for the body wraps. I measured off my 1/100 model and cut the sheets to strips of proper width. Since the sheets are only 6" wide they needed to be put on in sections to do the entire circumference.

The only drawback to this whole process was the need for a good seam between joints. It turned out rather well.

I masked off three or four rib spacings on either side of a joint, filled it, then sanded smooth. From three feet away you can’t even tell. Painting made it even less noticeable.

The overall effect with the corrugations is well worth and minor cosmetic issues.

For this assembly I used the ring previously cut from the main body tube, a cut down 5.68" tube coupler, a 3" LOC body tube, a ¼" thick ply 5.68"/3.00" centering ring reduced to 4.75" diameter, a poster board LEM shroud, a paper nose cone and a 3" tube coupler as a nose cone base.

I epoxied the cut down centering ring into one end of the main body tube ring. I left about an 1/8" exposed at the top for the LEM shroud to attach to. I then cut down the 5.68" tube coupler so it would fit in the main body tube. I left about an inch and a half shoulder to seat into the main body tube.

The coupler also has a slot or keyway that fits the doubler in the main body tube. This feature prevents the nose section from rotating on the main body. After the couple tube is set and a good fit achieved I epoxied a solid ply bulkhead at the bottom of the couple ring. The screw eye of the recovery system will pass thru here and it makes a nice solid base.

Next I epoxied in the 3" service module body tube. Alignment was an important issue here so I took my time and made careful measurements. This was to make sure that the completed assembly wouldn’t look crooked when the whole rocket was together.

After the epoxy cured I installed the paper LEM shroud. I had drawn out and cut this pattern earlier then put it together using super tacky glue and an iron. Basically you attach the glue tab to one edge of the seam, let it dry then apply the same glue to the other half of the tab and let it partially dry. Let your iron heat up while you do this, not too hot though, about 300 degrees should be fine (I use a monokote iron for my model airplanes).

You will also need a dowel of some sort to back up the joint when you iron it. I use a scrap piece of closet hanger dowel rod. Let the end of the dowel rod hang over the end of your workbench ans support it so it will take some pressure when you iron. Then tak your shroud, align and join at the seam, slip over the dowel rod and iron the seam. You won’t have to hold the iron there long. Move it up and down the length of the seam for a few seconds. The glue will re-activate from the heat and produce a strong bond.

I then fit checked and aligned the shroud to the body tube and base. When everything was where it needed to be I epoxied the assembly together. To make the shroud more durable I glassed it with ¾ oz. glass cloth and Z-Poxy finishing resin. After sanding to remove excess cloth I filled the weave with lightweight spackle and sanded smooth.

The Command Module capsule came next. I had sized the paper pattern from the Estes 1/70 scale version so it would fit on the 3" body tube. I photocopied it onto cardstock. The pattern has panel lines and details marked on it. Since my model will replicate an actual launch condition vehicle these markings are not required.

The boost protective shroud is all white. The pattern on the Estes sheet is basically an arc and if you cut it out as shown by the lines you will get a conic section with no tip. That’s because the Estes kit used a balsa turning for the top of the cone. I modified the cut by extending the seam edges up to the theoretical center of the arc lines.

When the pattern was folded and ready for joining I had a cone. There was a small hole at the tip due to the nature of trying to make a paper cone. I’ll tell how I dealt with this later. I overlapped and glued the seam with my super tacky glue and let it dry.

I then cut a 3" tube coupler section to about 1" in length. This is the shoulder of the nose cone. Once again I measured carefully to make sure everything was aligned then temporarily CA’d the coupler in place.

I then ran a bead of epoxy around the inside joint between the cone and coupler. A paper cone is a bit flimsy so it needed some reinforcing. I inverted the cone, mixed up a larger than normal amount of 15-minute epoxy and poured it into the inverted coned. This plugged up the small hole at the tip and added some nose weight.

I used my heat gun for monokote to get the epoxy to flow better. Heating epoxy has the addd benefit of making it cure faster. After the epoxy cured I sanded the tip to shape and was ready to glass it. I glassed the outside of the cone with ¾ oz. glass cloth and Z-poxy finishing resin. I made sure to put tape around the coupler so I wouldn’t mess that up. After the epoxy cured I removed the excess cloth, filled the weave with lightweight spackle and sanded smooth.

I now needed to add some base pieces for the LES tower. These were 3/16" dowel sections cut with a matching angle to the capsule so the tops would be parallel to the ground plane. I held some sandpaper on the cone and sanded the mating surfaces of the LES bases to match the cones contour. After they were all shaped and correctly sized I CA’s them in place. I filled any gaps with liteweight spackle and sanded smooth.

Next I located the centers on each dowel top and drilled a 1/16" hole for the support wire I was going to use to attach the LES tower to the nose cone. The basic LEM/Service Module/Command Module stack was now completed. There would be extra detailing to come later.