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.

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.