1/144 Saturn I Block II SA-5 Build Update 6

Progress continues on the SA-5 model.  I made the decision to replace the S-IV that came in the upgrade kit with my own that I would make out of some resin that I already had.  This would give me a round S-IV stage that would match the interstage without massive amounts of filler and hours of sanding to get it round.

I started by gluing three rods into the bottom of the interstage part.  Next I glued a circle made from .010 sheet stock to the top of the three rods.  I applied thick CA to the edges to seal the circle to the inside of the interstage.  This would be the bottom of the S-IV mold.  I had previously decided that I was going to be displaying this model as a complete stack without separable stages.  This allowed me to pour the new S-IV to the top of the interstage. I then glued a section of cardboard tube to the top of the styrene circle to make the walls thinner and lighten the model.

Anyway, I also cut a section of cardboard tube that was 1.5 inches in diameter on the inside, which almost exactly matches the interstage diameter.  I glued a strip of styrene to the top of this tube to give me a physical indication of how far to sand down the top when the resin cured.  I coated the inside with thin CA glue to seal the cardboard and then gave it a light sanding to remove some of the surface roughness.  Next I sprayed the inside with some mold release to hopefully make it easier to remove the tube after casting.  I also drew a line on the inside so I would know how far down to push the tube over the interstage to get the correct S-IV length.

Outer tube of S-IV mold.

I slid the outer tube over the interstage and then prepared to mix and pour the resin.  My resin is getting a bit old and part of the resin was starting to separate out.  I stirred it well to get a smooth resin and then measured out equal parts of resin and hardener and mixed them together.  I poured it into the mold to just below the top edge of the styrene strip inside the tube.  Unfortunately there was still too much air in the resin after I had stirred it up and the cured resin expanded and rose up out of the top of the tube.

This was not exactly desirable, but I could just cut off the excess and then remove the outer tube and it would be fine.  Except that after removing the outer tube, I could see that the extra air caused a bunch of bubble holes that would need filling.  Oh well, at least it is round and all I have to do is smooth the outer surface.  I sanded the top down to the indention made by the styrene strip and now I had a round S-IV with the proper length.

At this point I decided to add a few details to the interstage.  It needed standoffs for the three gaseous hydrogen vent pipes and also needed to have the camera canisters added next to the stub fins at positions 1 through 4.

I then sprayed on a first coat of primer.  Then glued on the S-IV interstage and sanded the junction with the S-IV body to a more rounded profile.

S-IV interstage added and sanded.

I sprayed a coat of primer on the S-I stage and did a bit of additional filling and sanding on some of the fins.  Next I sprayed on a final coat of primer to complete the S-I stage.

That’s it for now.  Much more work to be done on the S-IV stage. Thanks for looking.

 

1/144 Saturn I Block II SA-5 Build Update 5

A little more work on the S-I stage.  First I took out my Dremel and thinned the walls of the eight H-1 engines.  The kit engines have nozzle walls that are far too thick.  The picture doesn’t show it well but the walls are much thinner that before.

Engine on the left has been thinned, the right one is original.

Next I glued on the stub fins with CA.  When those were cured I added the large fins at Positions I, II, III and IV.  After those set I added the hydrogen vent extensions to three of the stub fins.

Finally, I glued on the inboard H-1 tubopump exhaust fairings.

Now the S-I stage is now complete and ready for it’s first coat of primer.  That will allow me to see where the final rough spots are and get them corrected before painting.

Here is a summary of what I added/deleted from the kit/upgrade parts.

  • All ribbing was removed from the base of the boat tail replaced with 14 ribs between each of the eight fin locations.
  • Access doors were added between each fin location and umbilical panels were added at two locations.
  • The engine fairings were removed from the base and glued back on after removing excess plastic.
  • Flame curtains were added for the four outboard H-1 engine locations.
  • H-1 nozzle walls were thinned.
  • About 1/8 inch of top of S-I was removed.
  • Kit fuel/LOX tank locators were trimmed before gluing the tanks in place.
  • Kit antennas were removed and antenna panels were added over kit locations and corrected antennas were replaced.
  • Electrical conduits were added to each of the four RP-1 tanks.
  • Gaseous hydrogen vent lines were added at three locations (replacing the update parts).
  • LOX and RP-1 fill and drain lines were added.
  • Vents were drilled at the top of three of the LOX tanks.
  • Vents were drilled at the top of two of the RP-1 tanks.
  • An umbilical door was added at the top of one of the LOX tanks.
  • Hydrogen vents were added to three of the stub fins.

Now it’s time to start on the interstage/S-IV stage.

Thanks for looking.

1/144 Saturn I Block II SA-5 Build Update 4

Here is a quick update of the SA-5 progress.  I glued on the antennas, the umbilical door, and the hydrogen vent pipes.  The umbilical door is cut from .005 sheet stock while the antennas are cut from some strip stock I had that looked close.  The hydrogen vent pipes look a bit different that the last update.  I added the short straight section after the bend at the top of the pipes.  I at first thought I could leave it off, but the more I looked at it the more I knew that the short sections needed to be added.

Some of the details on the upper part of the first stage.

The bottom of the vent pipes needed to have a slit cut into them so they could fit over the stub fins.  Also note that I have glued the fairings back on the base of the vehicle.

Slit for stub fins added.

Here are a couple of pics of the stub fins dry fitted to the hydrogen vent pipes.  Note in the pic on the left that I have also drilled the vent holes in the tops of the fuel and LOX tanks.  The pics also show the LOX and fuel fill and drain ports.

I also fashioned some hydrogen vents for the stub fins that will be glued on later.

Hydrogen vents for stub fins. Just a dry fit here.

I have also filled the areas on the inboard nozzles where Airfix had molded in for the turbopump exhausts.  The inboards on the Block II vehicles exhausted their turbopumps out the sides of the boat tail in aerodynamic ports which are not yet installed.  The outboards will require some modifications to look more like the real thing.  The inboards need some extra details as well, they were not simple curved bells.

That is it for now.  Thanks for looking.