Last time, I described how I needed to extensively modify the front and back ends of the Revell S-IC stage, using resin parts from RealSpace and New Ware, combined with some custom decals and a little scratch building.
Next, I needed to assemble the component parts of the stage—the fore and aft skirts, the intertank ring, and two styrene sheets that needed to wrapped into cylinders to represent the fuel and oxygen tanks.
As usual, I turned the styrene sheets inside out, so I could prime and paint the stage in a uniform pattern of black and white. (New Ware provides decals for the USA markings and the American flags.) Also visible in the picture above are the parts for the two long service tunnels that carried wiring up the outside of the tanks. The kit parts are undetailed and oversized, and New Ware’s solution to this is to provide a set of photoetch parts, ribbed to reflect the real surface of the service tunnels. These are supposed to be wrapped around the kit parts, and excess plastic pared away. The kit parts don’t really produce the right shape, unfortunately—the original tunnels were pretty close to being hemicylindrical. So I wrapped New Ware’s photoetch around lengths of 7mm half-round rod from Maquett instead, which produced a fairly nice result.
At this point, I noticed that New Ware’s tunnels were a little shorter than the kit parts. I checked against David Weeks’s Saturn V scale drawings and found that New Ware was pretty close to the correct length, and thought no more about it. (In retrospect, I should have thought more about it.)
So I wrapped the styrene, assembled the stage … and discovered that the service tunnels didn’t span as far as they should. I could have one end of the tunnel correctly located, but the other end wouldn’t reach far enough on to the skirt at the opposite end of the stage. More measuring ensued, and it turned out that Revell’s S-IC stage is almost an inch too long for the correct scale, with most of the excess length in the forward tank and the intertank. Well, sigh—they finally caught me out. I couldn’t see a good way to disassemble the pieces and trim them, so I accepted the inevitable and positioned the tunnels so that they leave a larger chunk of forward skirt exposed than they should do.
Note added in retrospect: I’ve had an enquiry about the detail of “almost an inch too long” in the paragraph above. I went back to David Weeks’s plans, and made some less rushed measurements of the kit parts. I ended up with the following little spreadsheet:
The “station” is the distance in inches above datum for the real vehicle. “Height” is the derived height of each vehicle section, which is then converted to 1/96 scale (third column) and compared to the corresponding kit part (fourth column) with the error in the final column. So the forward skirt and intertank are each about a quarter of an inch too long, the forward tank is about a third of an inch too long, and some minor shortfalls in the lower sections reduces the overall error to six tenths of an inch.
The engine fairings I kept separate, and painted in their final pattern of white, black and metallic. They were going to have to go on after I’d added the engine and firewall assembly I completed last time—the structural braces inside the engine fairings meant that each fairing assembly would need to be slid on sideways once its corresponding fairing firewall was in place.
So I primed and painted the cylindrical stage, leaving the final demarcation line between black and white on the aft tank to be completed once the fairings were in place. Then the firewall and engines were put in place, double-checking the correct orientation of the central engine. Then the fairings, then the finalization of the black stripes on the aft structure.
By this time, the whole thing was beginning to take up a lot of room on the workbench. Here it is, waiting for a coat of gloss and the New Ware decal set:
Positioning the American flags on the overlong forward tank needed a bit of calculation to make sure they were positioned in the correct proportion between the top and bottom margins, rather than working from the original measurements.
Finally, before the last coat of varnish, I added the delicate telemetry antennae to the forward skirt. (I knew that, if I added them any earlier, I would knock them off while preoccupied with decal positioning.)
And that was that. The literal final stage of this project:
Except … there’s one more small component to build before the project is complete. That’s what I’ll post about next time.
Addendum: I recently had an enquiry about my placement of the yellow drain labels at the top end of the aft tank. There are eight of these, placed just below the intertank section, at the top of each black and white stripe. They’re often depicted as being centred on the stripes (for instance, in the New Ware decal guide), but that doesn’t actually seem to be the case, at least in the S-IC-6 of Apollo 11. Looking at footage of the real launch vehicle from Apollo 11: Men On The Moon, by Spacecraft Films, I noticed that the labels were a little displaced from the centre line. Here’s a screen-grab to show the real positions, which I reproduced on the model:
And another addendum: When I pronounced this stage finished, I’d forgotten one little detail I planned to add. For some reason, the New Ware detail set doesn’t include a pair of liquid oxygen vents at the upper edge of the forward skirt. I’d planned to scratch-build a depiction of these, but clean forgot.
So, I recently remembered. At the same time as producing the external vents, I thought I’d do something about the bare oxygen tank dome provided in the kit:
This has the advantage of having the right number of gores in the right position (in contrast to the horrible S-II tank), but it omits some prominent pipework—the interior run of the LOX vent pipes, and a gaseous oxygen distribution line that linked the tank dome to one of the service tunnels.
So I put together some extra detail from styrene and brass pieces:
Here are the external LOX vents in position:
(I know, I know, you can hardly see them—look at the upper end of the right edge of each black stripe):
And the tank dome detail:
The match between internal and external detail is not exact, because of the aforementioned length issue with the forward skirt, but it’s an improvement on the previously bland dome.