It’s been a while, time for an update on the SA-5 build.
There are quite a few details that need to be added to the S-IV and interstage areas. But before that I needed to add the payload section to the S-IV interstage. There are a lot of details that go on the S-IV interstage and that would make it harder to get a relatively smooth transition from the S-IV interstage to the payload section (which includes the instrument unit). I used CA to bond them and then started filling and sanding the areas to get a fairly smooth joint.
I then added the tunnel that runs down the side of the S-IV just to the left of Pos II. This was made by laminating two strips of .010 x .100 strip stock. I didn’t have any .020 x .100 stock so this worked out fine. I also cut and shaped some .005 styrene sheet to make the antennas and an access hatch for the S-IV interstage.
I added two retrorocket fairings to the top of the S-IV interstage. I thought about making some from styrene rod, but then it hit me to check my spare parts stash. I had built a Saturn V last year from a mash up of the Monogram and Airfix kits, so I had a spare Airfix S-II. It had retrorockets on the S-IVB aft interstage. I pulled it out of the stash and checked it. The angle was similar to the angle of the S-IV interstage and the size of the molded on retrorockets looked good. I got my chisel blade out and shaved two of them off. I then glued them to the S-IV interstage.
I then started adding details to the instrument unit at the base of the payload section. It has several antennas, an access door, a rounded protrusion, and a panel that appears as though it may be somewhat thicker than an access door. There are also a couple of antennas at the base of the payload section just above the instrument unit. The documentation that I could find on the instrument unit is very sparse, but from photos and the few drawings I could find I think I have all the major details added.
I made the semi-spherical detail by sanding down a half pearl from a sheet I bought some time ago from Michaels. I originally used them as rivets for a steam punk rocket I built a couple of years ago. The thick panel was made from .010 sheet stock, the access door came from .005 sheet stock. I made the large antennas at Pos II and Pos IIII with .020 x .040 strip. The medium sized antenna next to the semi-sphere was made from .020 x .030 strip. The small antennas near a couple of the circular openings were made from .020 x .020 strip. The last antennas added were the two tiny antennas at Pos I and Pos III on the payload section. They were made from .015 x .020 strip.
Now it was time to add the fairings for the gaseous hydrogen vent pipes. For this I started with the conical section of the LH2 fairings from the donor S-II. I used white glue to temporarily attach them to a popsicle stick after cutting off the excess length. I then used sanding sticks and a #11 blade to form them to the correct shape. You can see them attached to the popsicle stick in one of the above pictures. I used CA to attach them to the proper positions on the S-IV stage. Then I cut some styrene tube (the same size I used on the S-I stage) to fit between the fairing and the base of the S-I interstage. The base of the S-I interstage has an angle so I needed to try and match that angle on my tubes. I then used Tenax to attach the front of the pipes to the fairings and CA to attach the base of the pipe to the S-I interstage.
Next came adding a small umbilical panel to the left of Pos II at the base of the S-IV. I used small sections of 3/64 rod to represent two of the pipes. I then used a 1/64 drill bit to make the 10 small holes between the pipes. I did not drill to the full diameter of the bit since the holes needed to be quite small. I then used a 1/16 drill bit make the larger umbilical hole above the 10 small holes. I again did not drill to the full diameter of the bit since the hole is smaller than 1/16 and also is not very deep. Once that was done I added the four ullage motors. I had to go the spare parts stash one more time to find a spare ullage motor since one of the ones that came with the conversion kit was not cast well enough to be used. The other two came from the S-IB kit that is the base of this model.
Finally, I could put a coat of primer over the S-IV/payload part and see how it turned out.
The only detail left to add are the four S-I retrorockets. They extend at an angle past the end of the S-IV section so I cannot add them until after I glue the S-I and S-IV sections together. After that it will be time to start painting the white base coat. I will not be using the conversion kit decals and instead will make some of my own. It appears that the checkerboard pattern that goes around the S-I interstage has 10 squares from one Pos to the next. The kit decals are off on that point. There are also some other markings that are not on the decal sheets. It is getting closer, but there is still quite a bit of work to do.
Thanks for looking.