1

NASA’s Saturn IB in 1:48 Scale

Part Two –

Ap7-KSC-68PC-185

Fabrication (Cont.)

The S-IVB upper stage consisted of the Aft Interstage Aerodynamic Fairing, the Aft Interstage (which on the actual vehicle is a large hollow structure that houses the J-2 engine and its thrust structure), the S-IVB Aft Skirt, propellant tank skin and the Forward Skirt. On top of this stage was the Instrument Unit (IU). As all of these cylinders had the same diameter I ended up building two similar cage-like structures to which I could attach the cylindrical skins. I originally thought I’d split the model at the interstage-aft skirt joint for transportation purposes so I built a sliding interface connection into the inner frameworks. The exterior skins for the upper part of the vehicle were vacuuformed in two large halves. The vacuuformed pieces for this included all of the above as well as the Spacecraft Lunar Module Adapter (SLA). After attaching the skins to the frames, the exteriors were prepped using the same techniques I had used on the first stage propellant tanks.

The basic vacuuformed shapes for the aft interstage, S-IVB/IU and SLA are in the upper photo while the cylinders for the aft interstage and S-IVB/IU are in the lower photo.

 

In the left image are the lower and upper second-stage support structures. On the right, the stage cylinders are added. The shorter one is the interstage structure and the longer one is the S-IVB and IU cylinder.

 

On the real vehicle, there were 112 external S-IVB interstage and aft skirt stringers, 1.375” by 1.00” in size, for the most part equally spaced around the cylinder. On the model, I chose to replicate these with 112 .030” by .020” Evergreen strips. To space the stringers I generated a plan view drawing of the cylinder with 112 equally spaced lines, sat each cylinder on this plan and ticked off the location for each stringer. Then using a long “L” shaped straight edge I penciled in their locations. Marking these points and transferring these lines introduced some error, which was expected, so to attach the stringers I made three guides. The first had the ideal width, while the other two were slightly thinner and fatter in width. To start attaching the stringers, I glued the four cardinal point stringers in place, being careful to keep these vertical on the cylinder, and then using the ideal width guide began to add the adjacent stringers. As I filled in each of the quadrants I kept a lookout for discrepancies, and when they showed up, which they did, I’d use either the smaller or larger guide to get the stringers “back in line”.

The forward skirt was similarly treated. The number of stringers was less (108) and their size smaller (I used .015” by .030” Evergreen strip) but the attachment technique was the same. On both of the skirts, the areas around the stage’s exterior umbilical connections and cable raceways covers caused the stringers to vary a little from the pattern and this was dealt with as the stringers were applied. All of the fairings, antennas and cable covers that protruded out from the second stage and instrument unit were made either from styrene sheet, vacuuformed shapes or a combination of both, After these odds and ends were created, some of these were applied to the stage prior to painting.

On the left is the S-IVB aft interstage after being marked-up. At the bottom work has started on the aft interstage aerodynamic fairing, a 27-inch tall corrugated structure, which covered the S-IB spider beam. The corrugations are faked using .030” half-round, 36 pieces were used for every 1/8 segment of the fairing. The image on the right shows the finished interstage. The larger fairings house the retro-rockets used to assist in separating the first and second stages during flight.

 

 

On the left is the S-IVB/IU with the upper and lower stringer pattern laid out. The horizontal lines drawn within each skirt indicate the rivet bands of the stage’s interior ring frames. The right image shows the stage in a final test fit after all the external detail has been added. A. forward skirt, B. instrument unit, C. aft skirt, D. external cable raceway, E. aft umbilical connections, F, ullage rocket fairing (1 of 3), G. auxiliary propulsion systems module, H. LH2 fill line faring, I. auxiliary tunnel, J. forward skirt umbilical connections, K. VHF telemetry antenna
On the left is the S-IVB/IU with the upper and lower stringer pattern laid out. The horizontal lines drawn within each skirt indicate the rivet bands of the stage’s interior ring frames. The right image shows the stage in a final test fit after all the external detail has been added. A. forward skirt, B. instrument unit, C. aft skirt, D. external cable raceway, E. aft umbilical connections, F, ullage rocket fairing (1 of 3), G. auxiliary propulsion systems module, H. LH2 fill line faring, I. auxiliary tunnel, J. forward skirt umbilical connections, K. VHF telemetry antenna.

 

The conical section that makes the transition from the instrument unit to the service module (the SLA) was treated the same as all the others and after the seams had been dealt with the external detail was added. The eight prominent hinge and upper panel corner fairings were laminated from two layers of an extra SLA piece and then sanded to shape. I used my Dremel drum sander to do most of the basic shaping with finer grit sandpaper blocks to refine the edges. After the shapes were finished they were attached to the SLA. The rest of the detail on the SLA consisted of .005”, .010” and .015” strip, all of which were glued down with Tamiya Extra Thin cement. As before, the locations of all of these details were taken from my original set of drawings and were then transferred onto the cone.

The Spacecraft Lunar Module Adapter (SLA). The image on the left shows the detail locations laid out in pencil. On the right, the detail has been added. The “saw-tooth” reinforcing strip at the bottom of the SLA is cut out of .005” styrene in four sections. Most of the rest of the detail is made out of .010” and .015” strip styrene.

 

The Apollo spacecraft Service Module (SM) started out with the two .040″ thick vacuuformed halves being squared up. A circular ring and disk were cut out of sheet styrene to keep the upper and lower edges of the SM in round. The butt joints of the SM were supported with “T” shaped re-enforcing beams that ran the length of the cylinder. The upper fairing on the SM was created out of a .030″ thick cylindrical section that was set back .040” from the SM exterior and the eight electrical power system (EPS) radiators were cut out of an extra vacuuformed SM skin. The raised radiator “ribs” were cut out of .010” by .030” strip and added to each radiator. I used a strip of .0150” by .020” below and between each of the EPS radiator panels. For the two environmental control system (ECS) radiators I glued two rectangles of .005” sheet to the SM cylinder and used .030” half round for the “ribs”.

On the left, the service module’s EPS radiator backing, outer skin and the upper and lower support rings. On the right the completed EPS radiators ring the upper portion of the CM. While on the lower portion, one of the ECS radiators has yet to have its half round “ribs” installed.

 

The SM RCS panels were cut out of .005” sheet and tiny “rivets” of .005″ styrene were punched and individually glued to each sheet to represent the bracket attach points for the RCS propellant tanks. I took a very fine hypodermic needle and filed the end to make the punch. The RCS quad housings were scratch-built and the 16 reaction control system (RCS) nozzles added, Glenn Johnson of RealSpace Models supplied the nozzles.

Three of the Service  Module’s RCS panel skins are attached to a wooden bock to allow for the raised detail to be added. The RCS panels on the SM are handed so two of these panels will be attached to the SM. The third is a practice or pathfinder panel. The rectangular shape on the right side of each panel is where the RCS quad will be attached.

 

I choose not to replicate the command module as the boost protective cover (PBC) covered the entire CM. The PBC skin was vacuuformed over the original command module (CM) form with a .040″ styrene CM skin in place. The additional thickness at the apex was created with a second, thinned down PBC skin. The external details were cut out from an additional BPC skin and styrene sheet of various thicknesses.

The BPC includes two circular window openings. One over the hatch window and the second over the left-hand rendezvous window. The hatch handle fairing has yet to be attached and the cutout for the CM-SM umbilical has not been made. Note the blow-out ports over the CM RCS Thrusters.

 

The launch escape system (LES) rocket motor skin was also pulled off of a wooden master as was the structural skirt. The external details added included the two jettison motor nozzles, external cable conduits and on the aft skirt, the tower attachment lugs and the four launch escape motor nozzles.

In the upper image are the major parts used to create the structural skit which transitions the LES tower to the LES rocket motor casing. The progression of the skirt in on the left and the LES escape motor nozzles are on upper the right. The lower image shows the underside of the finished structural skirt.

 

On the left are the vacuuformed LES motor casing halves with partially completed casing below. To the right is the shape that was used to create the LES jettison motor nozzles. The right image shows the complete LES motor casing and structural skirt.

 

To construct the lattice-like tower for the escape system, I used Plastruct .080” and .060” rod and made a jig to build the tower sides. I made up four sets with two of them containing the outer legs. I then attached these four sets together using the upright portion of the jig to align the sides. The ring, which is included near the top of the tower was cut out of a solid chunk of .060” sheet stock and when finished, was placed in the upright jig with the pre-assembled tower around it so that the eight upper support tubes could be added. After this had dried I removed the tower from the jig and added the eight lower ring tubes.

In the left image is the jig for making the Launch Escape System’s truss tower. The right-hand portion of the jig shows the layout for the truss itself while on the left-hand side is the tower assembly area. The cylinder holds the ring level and at the correct height. The right-hand image shows the Boost Protective Cover (BPC) and LES combination after all detail work was completed.

 

Constant dry fitting of parts and sub-assemblies was essential as the build progressed, and after several overall dry fits I was confident in the procedures that would be necessary to do the final assembly.

Test fitting of all components was done constantly. The left image shows an early test fit of the LES, BPC, SM and the SLA. On the right is the final test fit of these same elements.

 

The left image shows a test fit after all the major sub-assemblies had been built. On the right is the final test fit prior to break down for painting.

 

Painting

The sub-assemblies were primed with a mix of Gunze’s Mr. Surfacer 1000 and Mr. Thinner. Any seam work left was taken care of by brush applications of Mr. Surfacer 500, sanding sticks and the reapplication of the primer where necessary. I used Tamiya Flat White (XF-2), Flat Black (XF-1) and Dark Green (XF-61) for the majority of the model. I was going to blue my white and take the black down a bit but I had no idea how much paint was going to be used to finish this model so I used the colors straight out of the bottles. The engines were painted with Alclad II Steel, buffed out with some SNJ polishing powder and then lightly over sprayed with Alclad II Aluminum. On the service module I used the Tamiya White and a 50/50 mix of Alclad II Dull Aluminum and White Aluminum.

This detail shot of the aft interstage and S-IVB aft skirt includes the following: A. S-IVB auxiliary propulsion system (APS) Modules, B. the S-IVB aft skirt umbilical panel,  C. interstage personnel access panel, D. vertical motion tracking markings, E. aft interstage aerodynamic fairing,  F. ullage rocket motors and fairings, G. camera tracking markings, H. interstage retro-rocket fairings and I. the top of the first stage antenna panels and their antennas. Details A., F., and H. were all painted separately and then added to the finished model.

 

I knew that the paint masking was going to make or break this project and there was quite a bit of it to do. The most challenging involved the horizontal black and white separations that cross the stringers on the S-IVB stage. After I’d gotten the white paint to the state I wanted my first masking attempt involved cutting some intermediate lengths of Tamiya masking tape about 3/16” wide and simply laying it first on the top of a stringer, burnishing it down the side, across the cylinder face up the side of the next stringer and so forth. When I had finished applying one of these masking strips the corners between the stringers and cylinder had all pulled up just a little and I couldn’t get them to sit back down. As I couldn’t figure how I’d fill these little “holes”, even with a liquid masking agent and keep the edges straight, I knew this technique wasn’t going to work.

After a bit of musing I came up with a plan “B”. As the “valleys” between each stringer were made up of three planes, I decided to attach a separate piece of tape to each of those surfaces. This would make for a laborious application but eliminate the corner issue. I ended up cutting Tamiya masking tape to the same height as the stringers and using short segments, about 1/4 “ long, taped each stringer side. The “valleys” were filled with wider pieces cut to fit between the stringers. To complete the edge masking, I added a wider strip along the top of the stringers but set back a little from the actual separation line. I then used liquid latex as a masking agent to fill-in between the areas were there was no tape as well as to seal all the edges between tape pieces. It took over four days to do all of the masking on the S-IVB and Aft Interstage and a little over two days to paint and remove the masking. The results were better than I had figured I would get going in. There were some small over-sprays where I didn’t quite get enough liquid mask and some black touch-up where the tape wasn’t quite straight but overall the process worked quite well.

The steps involved in masking across the stringers. Fig. A shows the three adjacent pieces of tape that defined the “valley” around sides of the stringers. Fig. B shows the larger piece of tape that is placed over the stringers but slightly lower that the actual masking line. Also the liquid masking agent used to “fill in” the lower end of the valley is shown. Fig. C shows the liquid masking agent that is filled-in between the three adjacent tapes on the top of each stringer.

 

The S-IVB forward skirt/IU interface. The results of masking across the stringers can be seen. The metallic gray and white antennae were painted separately and attached during the final assembly. The two adjacent white tracking markings were made out of five separate pieces of white decal film for each rectangle. The two black holes are skirt vents and were made out of .005” styrene sheet with the oval shape cut out. The vents are backed with a light-blocking box

 

Decals and Finishing

Rick Sternbach of Space Model Systems supplied the decals for this project. I did some preliminary research but Rick fleshed out the details and produced a one-off set on his Alps printer. (Later Rick produced a similar set that was printed by Microscale.) For the “UNITED STATES” and “USA” lettering I cut away all the carrier film and using a simple paper guide, spaced the letters on the tanks accordingly. Doing this certainly made these a little harder to apply but the resulting lack of decal silvering more than made up for the extra hassle.

As much of the decal carrier film as possible was removed. On the large lettering decals that included all of the internal areas.

Rick also supplied a set of decals for the Apollo Command and Service Module that I used on the payload portion of the build.

After all the decals had been applied I used Testors Metalizer Sealer as the finish coat for the major sub-assemblies. I had used this before on one of my other projects and liked the subtle sheen it gave to the model. The last sub-assemblies constructed were the four sets of air scoops and the eight vehicle hold-down assemblies, which were attached to each fin. With the completion of all of the sub-assemblies I was able to turn to final assembly of the vehicle.

The first stage thrust structure after the engines, air scoops and stainless steel model support rods have been attached.

 

I used several different glues to attach the whole thing together. 90 and 5-minute epoxy attached the major sub-assemblies with Testors squeeze bottle cement and Aleens Tacky White Glue used to adhere the antennas and other smaller bits and pieces. When all was finished, the completed model stood about 57-1/4” tall with the outer diameter of the fins being 10-3/16” and the S-IVB cylinder diameter around 5-7/16”.

While it took over 20 years to see fruition, the actual modeling work was done between 2003 and 2010, with the majority of that over the last two and one half years. The shear size of this model taxed my workspace to the max. I had first stage fuel tanks and fins hanging from nails in the edges of shelving and upper stage cylinders placed on PVC ring stands all over my workbench. During the process I made extensive use of a “Lazy Susan” for both painting and building. In the end I figured I had cut over 3,600 pieces of styrene and used over 12 jars of Tamiya and Gunze paints. I finished the model about two weeks before the 2010 IPMS/USA National Contest and Convention in Phoenix where it won multiple awards including the Judges’ Grand Award “Best of Show”.

 

Reference List –

Just some of the documentation used to create the drawings for this model;

Saturn IB News Reference

GC 1044 September 1968

A PDF copy of this document is available through the University of Alabama at Huntsville Salmon Library.

 

Skylab Saturn IB Flight Manual

September 30, 1971

A PDF copy of this document is available through the NASA Technical Reports Server.

 

Apollo-Saturn AS-207 Vehicle Systems Information Drawings

Chrysler Corp. Space Division – Systems Engineering Branch

A PDF copy of this document is available in the Apogee Book “Saturn 1/1B” by Alan Lawrie.

 

Saturn IB Orientation – Systems Training Manual

Chrysler Corp. Space Division – Systems Engineering Branch

A PDF copy of this document is available through the University of Alabama at Huntsville Salmon Library.

 

NASA Apollo Command Module News Reference

North American Aviation (NAA) 1968

A PDF copy of this document is available through the NASA Technical Reports Server.

 

Rick Sternbach’s Space Model Systems decals are available through –

http://www.culttvmanshop.com




NASA’s Saturn IB in 1:48 Scale

Part One –

Ap7-68HC-561

A brief history and Vehicle Description

The uprated Saturn I (also called the Saturn IB) was the second of three launch vehicles developed to implement the primary goal of Project Apollo, “to put a man on the moon and return him safely to the earth”. By uprating the first stage of the Saturn I and replacing the Saturn I’s S-IV second stage with the S-IVB stage being developed as the third stage of the Saturn V, a launch vehicle with a payload capability of 35,000 Lbs. would be realized. When this launch vehicle was officially introduced to the public in July of 1963, most of the engineering work of mating the proven S-I first stage, whose development started in 1957, to the S-IVB stage had already been accomplished. This vehicle would allow NASA to test several major elements of the Apollo lunar mission on an earlier time frame than if they had waited for full development of the Saturn V. The Saturn IB also pioneered NASA’s Office of Manned Space Flight mandate for “all-up” testing; having all major launch vehicle and payload hardware functional on all flight tests. While first flown in February of 1966, the Saturn IB also had the distinction of boosting the last Apollo hardware flown with the 1975 launch of the United States’ portion of the Apollo/Soyuz Test Project (ASTP). In all, NASA successfully launched 32 out of 32 Saturn vehicles (Saturn Is, Saturn IBs and Saturn Vs) with the Saturn IB contributing nine missions to that total.

Saturn IB Cutaway Graphic

 

The complete Saturn IB with an Apollo payload stood approximately 224 feet tall and weighed at launch about 650 tons. The specific vehicle I choose to model represents the one used on the Apollo 7 mission, the first manned Apollo flight. This vehicle consisted of the first and second stages, the instrument unit and the Apollo spacecraft. The first stage (S-IB) included a thrust structure, nine propellant tanks, eight fin assemblies and eight H-1 engines. Manufactured by the Chrysler Corporation, this stage stood 80.3 feet tall and had a diameter of 22.8 feet (40.7 feet if one includes the fins). The center propellant tank, which carried liquid oxygen (LOX) was 105 inches in diameter and was constructed from tooling derived from the Jupiter IRBM (Intermediate Range Ballistic Missile) program while the eight 70 inch diameter outer tanks [four for LOX and four for fuel (RP-1)] used tooling from the Redstone SRBM (Short Range Ballistic Missile) program. The H-1 first stage engines were developed and manufactured by Rocketdyne, a subsidiary of North American Aviation, and were based on the engines (S-3/S-3D) developed for the Jupiter and Thor IRBM programs. For the Apollo 7 mission, each engine developed 200,000 lbs of thrust for a total first stage thrust of 1,600,000 lbs.

The Apollo 7 S-IB First Stage at LC-34 Ap7-68HC-205

The S-IVB second stage, manufactured by the Douglas Aircraft Company, was basically identical to the third stage of the Saturn V and consisted of liquid hydrogen and oxygen propellant tanks and a single 200,000 lb thrust J-2 engine (also developed by Rocketdyne). This stage, which incorporated a common bulkhead between the two propellant tanks, was 21.7 feet in diameter and 58.4 feet in length. The Instrument Unit (IU) built by International Business Machines (IBM), was a three-foot tall, 21.7-foot diameter ring sitting atop the S-IVB stage. This contained the Astrionics system, (the vehicle guidance, control and instrumentation systems) which controlled the entire vehicle during the boosted portion of flight and while the S-IVB was in orbit. It was also nearly identical in layout and equipment to that used on the Saturn V.

The S-IVB stage at LC-37B being stacked for the AS206 mission, January 23, 1967. AS206-67-HC-26

The final element of this version of the Saturn IB was the Apollo payload. North American Aviation’s Space and Information Division was responsible for all elements: the Spacecraft/Lunar Module Adapter (SLA), the Command and Service Module (CSM) and the Launch Escape System (LES).

The NAA Apollo Stack – Apollo 7 mission. Ap7-68HC-564

The Apollo 7 mission, AS-205 was launched on October 11, 1968 from launch complex 34 at Cape Kennedy Air Force Station, Florida and splashed down on October 22, 1968 in the Atlantic Ocean. This mission was the first manned Apollo flight, which was an 11-day Earth Orbital test designed to check out the redesigned Block-II CSM. Commanded by Walter M. Schirra with senior pilot/navigator Donn F. Eisele and pilot/Systems engineer R. Walter Cunningham the flight was considered a complete technical success, which contributed to NASA’s decision to man the third Saturn V flight and launch it into lunar orbit two months later (Apollo 8).

Left to Right: Donn F. Eisele, Walter M. Schirra and R. Walter Cunningham. Ap7-68-HC-206

 

The Model – Fabrication

I’ve always felt that the Saturn IB was the most ascetically pleasing of NASA’s manned launch vehicles and the building of a 1/48 scale model of this vehicle had been a dream of mine for over 20 years. I started active research on the vehicle in the mid ‘80s and by the early 90’s I had enough information to draw up a preliminary set of plans. Soon thereafter I started turning the wooden masters from which the basic cylindrical and conical shapes of the vehicle would be vacuuformed. I used .040” thick styrene sheet for these initial pulls. As the 90’s progressed I would add to my inventory of pulled Saturn IB parts (especially first stage propellant tanks) and continued with my research as other modeling projects occupied my time. In 2003 I started construction on the Apollo spacecraft’s service module, the command module’s boost protective cover and the launch escape motor housing and skirt. Actual work on the launch vehicle began in 2006 with the assembly of the nine first stage propellant tanks.

The nine propellant tanks of the S-IB stage are stacked on their support disk. The tank skins have been sanded but no external details have been added.

As this would be the largest modeling project I had ever tackled, I decided to compartmentalize the construction and attempted to complete the majority of each section before moving to the next. Large detailed drawings were done for all of the major elements and smaller drawings were parted out as I progressed through the build. My primary challenges were in managing the numerous sub-assemblies and keeping the entire vehicle in “alignment”. I also incorporated several new modeling techniques during the construction process, these included reproducing the weld beads on the first stage propellant tanks, finding a workable method of reproducing many of the rivets on the vehicle and figuring out how to mask the horizontal portions of the black tracking markings across the stringers when it came time to paint.

Wooden male molds were turned on a lathe and the resultant shapes were vacuuformed. These female plastic parts created the major cylindrical and conical shapes. In the past, when I’d vacuuformed cylindrical tubes I would cut ring frames for the ends and reinforce the inside of the tube seams with “T” shaped styrene strips. For these first stage propellant tanks, I incorporated an additional step. To keep the tanks at the correct diameter throughout their length, I placed one-half of each tank in a simple jig and glued to the “tees” a solid rectangular piece of sheet styrene that ran almost their entire length. After gluing the cylinders halves together I filled the resultant seams with a “slurry” of Testors liquid cement and scrap styrene. This was heavily slathered into the seams and left to cure for several weeks before I began to work on the outside of each cylinder. I started by sanding the entire exterior of each tank with a 100 grit wet-n-dry sanding block. This got rid of the wood grain ghosting on the outside of the cylinders and faired down the seam areas. With finer and finer sandpaper grits, these surfaces become ready for the exterior details which would then be added.

First stage outer propellant tank jig. With tee-sectioned seam supports glued to both sides, one half of the propellant tank is laid in the jig. The long rectangular styrene strip has not yet been added.

Detail work on the outer propellant tanks began with the LOX and fuel vents (near their upper ends). These were created with a series of thin styrene disks punched out with a Waldron Punch and Die set and then glued to “washer type” shapes cut out of an extra vacuuformed propellant tank skin. After the proper size holes were drilled out, the vents were centered and glued on to the inside of the tank walls. The first stage propellant tank weld-lands were created using Plastruct .010” by .010” strip styrene which was glued down with Tamiya extra thin liquid cement carefully applied with a 0/001 brush. First, I drew out the locations for the lands using flexible straight edges. For the horizontal lands I taped one end of a strip at the back of the tank and gently stretched the piece around the circumference on each line and applied the glue. The verticals were cut to length based on the locations of the horizontal pieces. After the lands had set up I applied 3M Blue Painters Masking Tape around all of the strips to protect the cylinder and using a riffer file gently removed over half of the thickness of each land. After cleaning the residue off of the raised edges with the cut end of a toothpick, fine grit sanding sticks were used to gently bevel the remaining thickness. Any little gaps between the beads were then filled and sanded.

A close-up look of the upper end of the S-IB outer propellant tanks. On the left is a LOX vent next to the two antenna panels, to the right of the panels is a fuel tank personnel access hatch and then a LOX tank attach structure for the spider beam. Below the antenna panels can be seen the weld-lands on the propellant tanks.

To properly set the bottom of the tanks in the thrust structure, nine .040” thick disks were cut to the inside diameter of each of the tanks and attached to a larger disk cut from .030” thick sheet. This larger disk became the upper stiffening support for the thrust structure cylinder. A similar disk was cut which would hold the H-1 engine nozzles and between these two disks, 1/8” thick styrene walls were sandwiched to further solidify the thrust structure.

The first stage thrust structure. On the left-hand image the upper support disk is at the top with the 1/8” thick stiffing webs and brass support tubes in place. The lower support disk is below and the paneled heat shield to the right. The right-hand image shows the basic thrust structure assembled with the locating disks for the propellant tanks attached to the upper support disk.

After the exterior of the thrust structure cylinder was cleaned up the external details were added. On the real vehicle, the bottom half of the thrust structure is hollow and the exterior skin consisted of sixteen alternating panels, eight being corrugated and eight smooth. Using .060” half round Evergreen strip I applied them in eight groups of fourteen strips, simulated the corrugations. On the upper half of the thrust structure other exterior details included eight personnel access panels, the openings for the two aft umbilical receptacles and location stubs for the eight fins. On the real vehicle there were many rivets on the outside of this cylinder so I chose to replicate their locations with a quick spin of a micro drill. The tedious part of this process is in the layout while the actual dimpling didn’t take that much time. However the number of rivets does add up, on the entire model I ended up replicating more than 12,500 rivets which is no where near the total on the real vehicle.

All of the outer detail on the thrust structure has been finished. The “corrugated” panels, access hatches, one of the umbilical ports and the fin attach details can be seen. Barely visible are the rivet patterns on the cylinder. One fin and its attachment gussets are temporarily attached. The construction details of the 60° fairing can be seen as well as the attached fin extensions.

The fitting of the 60 ° fairings, which fairs in the area between the thrust structure and the outer propellant tanks, turned out to be a bit of a challenge. Originally I was gong to fit eight individual fairings, one around each outer tank. And then during the final assembly of the model attach them to the tanks and each other. However, as I couldn’t figure out a fail-safe method of accomplishing this I ended up gluing the entire fairing to the thrust structure and then cutting out the location for each of the eight exterior tanks. This allowed me to deal with any variations in fit around each tank. A paper pattern was drawn to indicate where each propellant should fit and those lines were transferred to the fairing. Using my Dremel motor tool with a small diameter drum sander, the plastic was carefully removed. Each of the openings’ final shape was refined with needle files and sand paper attached to wooden dowels.

Clockwise from the upper left, the 60° fairing fitted to the thrust structure and then the process of fitting each outer propellant tank.

I decided to replicate all eight first stage fins as opposed to making a master and having it cast. The sides for each fin were cut out of .015” sheet stock with the rest of the pieces cut out of .030” sheet.  To keep the fins consistent, I made a .015” plastic master taken off the fin drawing to make all of the fin sides. A similar technique was used to replicate the other fin parts. The outer surface of each fin side had panel lines inscribed while the interior upper edge was beveled to remove the excess thickness.

Build-up of the fins. The image on the left shows the major fin parts. The lowest piece is an internal stiffener to help prevent twisting. The right image shows three basic fins ready to be fitted to the thrust structure.

The bottom of the thrust structure was enclosed with a paneled heat shield. This was also cut out of .030” sheet stock, and after making the openings for the engines, panel lines were scribed. Two sets of masters were created for the eight engine nozzles that extend below this heat shield. The inboard engines included a sinuous turbopump exhaust duct while the outboard ones had an aspirator attached to the lower section of the nozzle. The one common piece of equipment for all of the engines was the heat exchanger itself. I made masters for these and asked Glenn Johnson of RealSpace Models to resin cast them. After I got the engine parts back from Glenn, I began the process of attaching the engines to the bottom thrust structure. The gimbaled outboard engine’s flame curtains, which kept the intense heat from the exhaust out of the thrust structure were made from Miliput Superfine two-part epoxy putty.

On the left is an inboard engine assembly with an outboard engine on the right. The outboard engine has a large hole drilled into it to accept one of the models four support tubes.

 

The H-1 engines are placed on the heat shield in a final test fit.

 

The top of the first stage propellant tanks were aligned by a structural element called a “spider beam”, similar to what was used on the actual vehicle. This assembly was also the support for the upper stage and Apollo spacecraft. I chose to replicate the majority of this transitional piece of hardware because I wasn’t sure how much of it would show when the model was done. I built up all the major “I” beam parts out of .015” strip stock and added additional detail. A plan view drawing of the finished spider beam was glued to a wooden base and a jig was created to keep all of the parts in alignment during their assembly.

The spider beam’s jig on the left with the three major beams being constructed. On the right is the drawing that was used to fabricate the various pieces that make-up the beams.

 

The left image shows the finished spider beam in its assembly jig. On the right the spider beam is shown attached to the propellant tanks. The styrene blocks on the top on the beam will be used to locate the upper parts of the model.

Part 2 –

NASA’s Saturn IB in 1:48 Scale – Part 2NASA’s Saturn IB in 1:48 Scale – Part 2




August 2019 Meeting

Our August meeting took place on Friday, August 30 at 6:30 PM at the Girl Scouts of America Campus on Upas Street. Manny Gutsche gave a presentation on the special and best of awards from IPMS Nationals in Chattanooga. We also had a lot of show n’ tell models.

Just a quick note – if attending a meeting and bringing a model for show n’ tell, please make sure to fill out a model information form and give it to Ethan, the webmaster, so that he knows what you built.