I wanted on this model a scale and durable LES (launch escape system) tower. I had previously made one for my Boyce Aerospace Redstone and modified it for flight use. That one had suffered minor damage from time to time but I knew I could build a better one. I decided to use brass tubing.

The Estes 1/70 version came to my aid again. The LES tower for that version used wood dowels glued together. I would substitute brass for wood and solder for glue. I scaled the Estes plans accordingly and built a jig.

All the horizontal crosspieces fit into the vertical legs because I drilled holes to accept them. These would be stronger joints because the parts would physically interlock and be soldered. I built the basic tapered box shape adding one side at a time. When I was done I carefully heated joints and aligned and straightened where needed.

I then started to add all the little diagonal cross members. The central ring was formed around a 3/8" drill bit shank and the ends soldered together. The whole process was not that tedious and took me about two to three hours over two days. The end result was worth it.

For the top of the tower where it attaches to the rocket motor I cut out a brass circle and soldered it to the top.

To this circle would be the lower shroud of the rocket motor and the motor tube and nosecone. The shroud was laid out and drawn on Unigraphics. The original Estes 1/70 kit had this as a balsa turning.

The rocket body was a BT-5 body tube cut to length with a balsa nose cone from my designer’s Special box. The pieces were all test fit and then put aside for assembly later.

The fins for this rocket were built up assemblies using .040" sheet styrene and 1/8" aircraft ply. I used the same technique that Estes’ 1/70 version used with a few modifications. I sized the patterns from the Estes plans.

Since the fins on the Estes 1/70 version were oversized for stability I knew that any enlargement would not be true to scale. This was fine with me since the model is sport scale and the extra fin area would help in stability. (More on this later)

I constructed a 3D model of the fin in Unigraphics and then plotted out all the required ribs full size for my patterns. The fin is a complex shape with tapers both running from leading edge to trailing edge and root to tip.

I then made a flat pattern of the fin skin to use as a template. I cut all the pieces out at once for all eight fins. A tedious process but in the long run it saves time and provides a consistency between fins.

I used CA to glue the ply ribs to the inside skin of one fin then CA’d the other skin on. CA glue does a good job of bonding wood to plastic. The fins are not designed to have TTW construction.

I had toyed with the idea but after careful consideration and weighing my options I decided against it. The root of the fin has a lot of bonding area and attachment to the base unit using 30-minute epoxy should be adequate. (this model will never see rapid acceleration; slow liftoffs are the goal here)

After all the fins were assembled any gaps were filled with lightweight spackle and then sanded smooth. Having fin skins of sheet styrene means less finishing and prep time for painting.

I now marked the lower body unit for the fin locations. The Saturn 1b uses eight fins so careful marking was essential. I then epoxied each fin one at a time.

After the epoxy had started setting I used my finger, dipped in alcohol, to smooth a fillet between the fin and body tube. Eight fins to epoxy on with 30-minute epoxy can take a while. When they were all done I once again looked over all the joints and filled in with spackle and sanded smooth.

The lower body unit has some corrugations on it as well and I duplicated these again with scribed styrene sheets used for the body wraps. These small sections were CA’d in place.

The outer body of the Saturn 1b has numerous conduits, ullage motors and fairings. I made these details from hard balsa carved and sanded to shape.

The grain was filled in, more sanding and then they were primed and painted. These items will be glued to the body tube after it has been painted.

The because of inaccurate body tube size relation ships when the lower fuel tanks are arranged around the core tube there is a gap between the fuel tanks when they are arranged.

To fill this gap and to make sure when I installed the fuel tanks they would be straight I CA’d 1/32" ply strips along the length of the core tube. This filled the gap between the tubes nicely.

The model is intended to be launched off a ¼" rod and that is the lug size I used. I did not feel the need for a larger rod size because the model will not weigh that much when completed and it will not ever be launched in high winds.

I positioned the lugs very similar to my 1/100 model. One lug on the lower body tube section near the fins and another one on the second stage body tube. I had to line up the upper body tube and the lower one because they do require correct orientation to one another for conduit and roll pattern alignment with regards to the fins.

The lugs were spaced off the body tubes to allow for the uneven diameters between them and I used a rod to align them while they were epoxied in place. When the rocket is final assembled a launch rod will be used again for alignment.

The rocket is now ready for paint. It was painted in sections very similar to the 1/100 Centuri version. This method involves less masking and easier handling of the parts. Even though there are only two colors, black and white, the various roll patterns and separation lines require careful masking and prep that a fully assembled model would make much more difficult.

The paint I used was Krylon. It is a good all purpose enamel that goes on well and dries quickly. It also has the advantage of flowing the colors back together between coats because of the solvents used. (this can help if you get sags or minor runs)

I primed the main body tube and the core tube/fin unit. This helped show any defects or areas that needed more sanding or filling. The fuel tubes were painted directly (since they were already white in color and I did not feel the need to prime them), four black and four white.

The capsule was painted glossy white separately as well as the LES tower and the LEM shroud adapter. I then painted the main body tube and core tube/fin unit glossy white. I let these dry for a day then masked and painted those areas glossy black.

It is important to note that on the corrugated areas to get a good seal between the tape and the previous painted surface. This is to prevent the new color from ‘bleeding’ under the tape. It is also important to let the color coat dry for a few hours before removing the tape to prevent lifting or tearing of the new coat.

The actual service module was a polished aluminum in color. It almost looked like chrome. There are no real accurate chrome type paints.

I could have used chrome self-adhesive monokote trim sheet. However, I did not have any and cleaning and use easily scratch the chrome in general. I did cover the service module section with aluminum colored monokote.

This was then detailed with various pieces of white trim monokote to simulate panels and radiators found on the actual vehicle.

Recovery for the Saturn 1b will be very similar to the 1/100 scale version. It will come down in two pieces with the separation line being at the base of the LEM shroud to second stage body tube interface.

The LEM/SM/CM/LES stack will come down in a nearly horizontal position via a single 36" parachute by use of a bridle fashioned from R/C aircraft control cable.

This bridle attaches to an eyebolt at the base of the LEM stack and to an eyebolt screwed into a blind nut at the base of the service module. This eyebolt on the service module is removable for static display.

The main body will come down via dual 36" parachute recovery. For the main body section I wanted to have it descend as close to vertical as possible to reduce stress on the fins at landing. This necessitates that the shock cord mount be as close to the centerline of the rocket as possible.

There are two eyebolts on either side of the core tube in the parachute compartment. A bridle sling made of 3/32" A/C cable connected with quick links connects to an apex point a few inches above the center of the core tube. This is where the shock cord will attach and then continue to the parachutes.

This rocket is not using any sort of altimeter based ejection system. The flight profile I intend will allow for a motor based ejection system. It might be possible to make provisions for one but I have not gone to the trouble to investigate the feasibility.