Category Archives: Building

Revell 1/96 Saturn V: S-IC Stage – Part 1

Having completed the S-II Aft Interstage for my previous post on this build log, I’ve now progressed to the Big Beast of the S-IC.

This stage is composed of Revell’s usual combination of moulded cylinders for the skirts and intertank, and printed styrene sheets to be rolled into cylinders for the tank sections. The stage also has two service tunnels running along its length, each one provided in two sections in the kit:

Revell 1/96 Saturn V S-IC stage
Click to enlarge

As with previous stages, my plan was to turn the printed sheets inside-out, paint them white to match the other structures, and then detail them using the decals provided in the detail set by New Ware. The kit service tunnels are both too long and too large, so need to be replaced—I’ll come to that in my next post.

For this post, I’m going to describe a small modification to the forward skirt, a rebuild to the aft skirt, and a wide-ranging replacement of the kit’s engines, fairings and heatshield.

As usual for this kit, the S-IC needs to be rotated to bring it into correct alignment with the rest of the stack. So the locating lugs on the forward skirt need to be moved. This is complicated by the fact that I have previously rotated the aft part of the S-II stage through ninety degrees so as to be able to conceal an unrealistic kit feature. Not having undone that rotation when I modified the S-II Aft Interstage (because that kit part is rotationally symmetrical), I need to reverse that rotation now. A corrective quarter turn would amount to moving the locating lugs 3⅜″ clockwise around the rim, looking down. Instead, judging from the position of the S-IC service tunnels, I found I need only three-and-a-sixteenth. (So it seems to me that, if you build this kit without rotating the aft part of the S-II, you’ll need to move the S-IC locating lugs five-sixteenths of an inch anticlockwise to fix the stage alignment. But please check my working.)

Shift locating lugs Revell 1/96 S-IC
Click to enlarge

As usual, the colours of the skirt interior and LOX dome are hard to ascertain. I used zinc chromate yellow-green for the tank on this stage, which matches the colour photos I’ve seen of the stage being assembled, as well as the apparent colour visible in the familiar footage of Apollo 4 staging.

At the other end of the stage, the big problem with the fairings and heatshield provided in the model kit is that they are rimmed with multiple air scoops, designed to drive cooling air across the heatshield between the engines and the fuel tank. These featured in early designs (on which the kit was based), but on operational Saturn V launch vehicles the scoops had largely been removed, leaving only a pair at either side of each engine fairing. So both need to be replaced with much plainer resin versions from New Ware.

Revell 1/96 Saturn V S-IC stage, NewWare replacements
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The kit engines also need to be replaced. Revell provides bare F-1 engine bells of the kind seen on the small number of Saturn V vehicles that are on display. But in reality, the F-1 engines on operational launch vehicles were swathed in external insulation called “batting”, to protect the engine bells from hot gases billowing back from the rocket exhaust. It looked like this view of a test item:

Batted F-1

(This photo rattles around the Internet uncredited, and I’ve so far been unable to find its source. If anyone knows, I’d be glad to give credit appropriately, or to remove a copyrighted item.)

Resin versions of the batted F-1 engines are available from RealSpace Models. Here’s a comparison of the kit version and the resin replacement.

Revell 1/96 Saturn V, F-1 engine and RealSpace replacement
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The batting consisted of both generic pads applied to the bell, and shaped sections which surrounded more complex structures. As the photograph of the real thing shows, there was a slight difference in the reflective properties of these two kinds of batting. I aimed to reproduce this by applying chrome-finish paint to the resin, and then adding bright chrome Bare-Metal Foil detail.

RealSpace’s resin engines are adequately shaped to locate them accurately on the kit heatshield. And New Ware’s resin heatshield is adequately shaped to locate the kit engines correctly. But the two detail kits don’t have enough locating studs to align them precisely with each other. So I sawed the locating studs off the kit engines, and cemented them to the resin parts, ready to engage with the holes in New Ware’s heatshield; and I drilled out the gimbal mounts on the resin heatshield, and added short sections of brass rod to engage with the sockets on RealSpace’s engines.

Then I needed to attach the gimbal actuators to the engines. In reality, these “fueldraulic” pistons steered the outer engines, and were supported on structures concealed inside the engine fairings. Each outer engine had two gimbal actuators, attached to its base by an open pyramidal outrigger. The kit provides each actuator and its engine outrigger as a single, poorly detailed part.

Revell 1/96 Saturn V gimbal actuators
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I used the kit heatshield as a gig to get the correct relative positions of each resin engine and its pair of actuators. Then I filled the open pyramid of each outrigger with clear glue, allowing the glue’s surface tension to gather it into a pyramidal tent-like structure—that was my way of reproducing the appearance of the real engine outriggers, which were wrapped in foil batting along with the rest of the engine.

After painting and the application of foil detail, here’s what the engines looked like:

RealSpace batted F-1 engines
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You can see that the centre engine sports a couple of vertical rods in place of gimbal actuators. This engine was not steerable, but still had outriggers attached, which were supported by rods attached to the heatshield. I scratch-built outriggers and rods for this engine, since the kit neglects that detail.

The New Ware heatshield is light on detail, providing only the outlines of the various tiles. In reality, the heatshield was dotted with rivets and other details, which you can see in this view of the Apollo 11 S-IC:

Apollo 11 S-IC 69-H-365
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NASA image 69-H-365

Guided by this photo, and John Duncan’s excellent reference photos of the heatshield of the S-IC displayed at the Kennedy Space Center, I drew up and printed a set of custom decals, which I applied, tile by tile, to New Ware’s resin part.

NewWare S-IC heatshield, custom decals
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The next problem was the subsidiary heatshields positioned within each engine fairing. Both Revell and New Ware provide simple rectangles, supported at their outer corners by the base of the gimbal actuators. These certainly match the appearance in the Apollo 11 photo, above. But notice how many panels have been removed in the Apollo 11 view—engineers were gaining access to the interior of the Saturn V until late in the pre-launch period. So in fact, the whole interior of each engine fairing was eventually blocked off by a lunate heatshield built up of several panels—the rectangle in the Apollo 11 view is only the central part of a larger structure. The whole structure is visible in the S-IC at Johnson Space Center—see, for instance, this photograph by Kevin A. Boudreaux.

So I scratch-built replacement fairing heatshields using styrene sheet.

NewWare S-IC heatshield and fairing, scratch built additions
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A little experimentation with paper revealed that these needed to be cut from discs 22mm in radius, if they were to fit New Ware’s replacement fairings at heatshield level. (In fact, they should have been slightly elliptical, since the fairing heatshields were tilted a little from the horizontal.) These little lunes then got their own custom decals, reproducing what I could see of the panelling in various views of the JSC Saturn V.

Finally, the whole lot could be assembled:

RealSpace batted F-1 and customized NewWare S-IC heatshield
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The Revell aft skirt also needed to be seriously modified, since it lacks hold-down posts. These were important components of the real launch vehicle, since they supported the entire weight of the Saturn V on the launch-pad, and at launch engaged with hold-down arms which prevented the Saturn V taking off until full engine thrust was achieved.

New Ware provides four resin parts, each of which requires a large, shaped slot to be fashioned to accommodate it. Starting with a series of hand-drilled holes, I expanded and shaped each slot before fitting the hold-down and epoxying it in place, only moving on to the next slot once the glue was dry.

Revell 1/96 Saturn V, preparing aft skirt 1
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Revell 1/96 Saturn V, preparing aft skirt 2
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Revell 1/96 Saturn V, hold down post in place
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Finally, a dry assembly to ensure that everything fitted together. Notice the internal fairing support struts, which are photo-etched parts from New Ware.

RealSpace batted F-1 and customized NewWare S-IC heatshield, dry fit
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Next time, I’ll complete my build of this stage.

Revell 1/96 Saturn V: S-II Aft Interstage

Having completed the S-II stage, I’ve worked my way down the stack as far as the S-II aft interstage—a ring structure interposed between the first and second stages to provide clearance between the S-II’s rocket engines above and the dome of the S-IC’s liquid oxygen tank below. We can see it being dropped astern in this video taken from the second stage of Apollo 4:
Also briefly visible in that video are the ullage rockets on the aft interstage, which were fired to shove the S-II forward just before its own engines fired. The whole stack was in free-fall between the shutdown of the first stage motors and the firing of the second stage engines, and there was concern that liquid hydrogen and oxygen would float around in the S-II’s tanks during this time, allowing gas bubbles to get into the mixture when the S-II engines fired. So the ullage rockets gave a little shove to the S-II, settling its fuel and oxidizer to the bottom of their tanks, next to the drainage piping, before the S-II engines were fired up. (Ullage is a nice old word originally referring to the air-space within a cask or bottle of wine. By extension, the unfilled volume in a rocket’s tanks is called ullage, and ullage rockets are used to make sure the ullage moves to the top, and the contents to the bottom.)

It turned out the S-II didn’t really need this precaution, and the number of ullage rockets on its aft interstage was reduced over time—from the eight visible on the Apollo 4 video, to four by the time of the Apollo 11 launch, and the last few Saturn V launches had no ullage motors at all on this stage.

So that’s the first problem with the Revell kit representation of this interstage—it has eight attachment points for ullage motors, and I only need four for my Apollo 11 launch vehicle. The second problem is that the kit parts for the ullage motors are the wrong size and shape—but I have New Ware resin replacements to deal with that. And the third problem is (predictably enough) that the attachment points are in the wrong places—Revell sites the eight ullage motors exactly on the principal axes of the Saturn V, whereas they were all displaced about 16 inches anticlockwise from those axes (looking down).

So all these mounting points have to go:

Revell 1/96 S-II aft interstage
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It’s a slightly harder job than disposing of the similarly misplaced mounting points on the aft skirt of the S-II, because these are big moulded structures that partially overlap the stringers on either side. So I first had to trim them level with the stringers, and then apply Dymo Tape to guide my razor saw and preserve the remaining stringer structure.

Revell 1/96 S-II aft interstage - removing ullage rocket locating tabs
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Then I used a 2mm chisel to remove all the excess plastic.

The other thing I needed to do was to mount the lower ends of the various fairings that I’d applied to the S-II. Many of these fairings extended across the flight separation line between the S-II and the aft interstage, and their lower ends were discarded along with the aft interstage (you can glimpse them in the Apollo 4 video, above). So I’d had to chop the ends off the New Ware resin parts when I mounted the fairings on the S-II stage. All these ends went into a pot, individually labelled, and now I was able to fit the interstage to the S-II and reunite all the severed parts (after chiseling away small parts of the stringers to make room for their attachment). There was also a personnel access hatch to be added, provided as a photoetch part by New Ware.

After priming, the final result looked like this:

Revell 1/96 S-II aft interstage - resin ullage rockets and fairings in place
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I attached the interstage to the rear of the S-II again at this point, so that I could ensure continuity of the black stripes which begin on the S-II and extend across the interstage to the forward skirt of the S-IC stage. I got all the masking in the correct place, and then separated the interstage again for painting.

The interior colour of the Apollo 11 interstage is another source of doubt. The only colour images I can find come from early Apollo missions. Although the interior looks yellow (or even pink) in the interstage jettison videos of Apollo 4 and Apollo 6, it’s being subjected to the rocket blast of the S-II’s engines in these images. But there’s a clear view of Apollo 6’s aft interstage during the stacking process on the ground, which shows its interior with a metallic finish.

Apollo 6 aft interstage during stacking
Source: Image Ap6-MSFC-6758331

So that’s what I went with.

Revell 1/96 S-II aft interstage + New Ware details 1
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I also added a flight-separation junction to the bottom edge of the interstage, using 0.5mm x 1.5mm styrene strip, which you can see in this view.

Revell 1/96 S-II aft interstage + New Ware details 2
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The lines along which the interstage separated from the S-IC stage below, and the S-II above, were slightly raised ridges, painted white, which provided clear visual lines of demarcation traversing the black stripes, even when the rocket was viewed from a distance:

Apollo 11 interstage
Source: Image Ap11-69-HC-622HR

My original plan had been to add styrene to the top and bottom of the interstage, but it became evident it would be easier and more secure to attach the upper flight separation line to the flanges on the base of the S-II. Here’s the result when the two are stacked together, which I think simulates the appearance of the real thing fairly well:

Revell 1/96 S-II + aft interstage + New Ware details 1
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Revell 1/96 S-II + aft interstage + New Ware details 2
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So now it’s on to the first (and for me, final) stage.

Revell 1/96 Saturn V: S-II Stage – Part 2

In my previous post of this build log, I eventually got the heavily modified parts of the Revell S-II stage assembled, and had replaced all the kit fairings with more correct versions from New Ware. A good coat of white paint brought all the disparate parts to the same shade, and then I added the black chequer pattern to the aft skirt, using the same masking techniques I used for the S-IVB aft interstage. Then it was time to add the five J-2 engines (which I prepared when working on the S-IVB stage) and the aft heat shield, supplied as a resin part by New Ware.

New Ware resin Saturn V S-II stage heat shield
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This heat shield was suspended about halfway down the J-2 engine nozzles, completely surrounding the central engine and housing the outer engines within cut-outs around its edges. Its job was to protect the underside of the liquid oxygen tank from the heat of the engines immediately below. Each engine was attached to the heat shield by a flexible skirt, to accommodate vibration and to allow for the steering of the outer engines. The New Ware resin part imitates these flexible skirts with rigid collars.

As I’d previously discovered when trying to fix up and paint the S-II thrust structure, the heat shield of the S-II is poorly recorded photographically. It seems to have been added in sections after the engines were installed—it’s certainly absent from delivery photographs of the S-II. And it’s omitted from the three surviving S-II stages that are on display.

One of the best photographs we have comes from the stacking of the Apollo 6 launch vehicle, though the flexible curtains are not yet installed:

Apollo 6 S-II heat shield
Click to enlarge
Source: Image Ap6-MSFC-6758331

Here we get a good view of the intricate support lattice that suspended the heat shield below the thrust structure. (You can also see a slab of something dangling off the underside of the heat shield—we can only hope it was a protective cover of some sort, rather than a structural component.)

In terms of colour, we have the interstage separation video from Apollo 4, which shows the upper surface to be brick red:
And for the underside there’s an image from the stacking of the Apollo 13 launch vehicle, slightly obscured by the presence of a work platform around the engines:

Apollo 13 S-II heat shield
Image archived at Ninfinger Productions as S-II_heatshield1_MOD.jpg.
(A screen capture of the Apollo 13 S-II heat shield from Spacecraft Films, originally posted by lindensims and processed to bring out detail by scottbro41.)

So it looks like the aft surface was very dark, if not black, and the flexible curtains were very pale, if not white.

That’s the colour-scheme I used, anyway.

The next problem was figuring out how to get the position of the heat shield correct, while still being able to insert all those support members. The solution I came up with was to epoxy the heat shield to the central engine, at the correct height (taken from David Weeks’s invaluable drawings). I built a little cardboard jig to keep things level while the glue set.

Assembling New Ware S-II heatshield
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A millimetre or so needs to be shaved off the protruding elbow of the engine’s fuel line to allow it to sit centred in the heat shield. I also used the fuel line as my landmark to get the heat shield correctly rotated, so that it would align with the other engines once assembled in place—careful dry fitting and a pencil mark was the low-tech solution to that problem.

After that, I installed the central engine and levelled the heat shield.

Revell 1/96 Saturn V S-II heat shield installation 1
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Revell 1/96 Saturn V S-II heat shield installation 2
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This gave me a nice space into which I could insert the support structure, a strut at a time, modelled in 0.5mm brass rod.

Revell 1/96 Saturn V S-II heat shield support installation
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Finally, the outer engines were set in place, and I added the various control packages provided by New Ware to the outside of the thrust structure. (In themselves, these are problematic, since there seems to be little consistency between the early Apollo 4 and Apollo 6 photographs and the three surviving S-II stages on display. I went with what New Ware provided, which was consistent with David Weeks’s drawings.)

Revell 1/96 Saturn V S-II aft assembly 1
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Revell 1/96 Saturn V S-II aft assembly 2
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The New Ware decals consisted of the vertical motion target (a black dashed line on the S-II which faced the launch tower) and four vertically printed “UNITED STATES” labels. All of these, being long and narrow, were excruciatingly difficult to get sitting perfectly straight and vertical. Eventually I hung a plumb bob from my modelling light, and used that to give me a vertical alignment against which I could gently nudge the decals into position.

Revell 1/96 Saturn V S-II 1
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Revell 1/96 Saturn V S-II 2
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Finally, I added the LH2 vent lines to the tank dome, so that they aligned correctly with LH2 vent valves on the forward skirt. (I also scratch-built a little rectangular telemetry package to sit on the tank dome.)

Revell 1/96 Saturn V S-II fore end
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And here’s the Position II view with the S-IVB aft interstage on top, just to check alignments.

Revell 1/96 S-II stage + interstage
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And that’s it for the S-II. Next up, the S-II aft interstage—which (you guessed it) needs considerable modification.

Revell 1/96 Saturn V: S-II Stage – Part 1

In histories of the Apollo programme, the S-II stage of the Saturn V is often referred to as “troubled”. There were difficulties with weight reduction that led to a delay in delivery of the first functioning S-IIs. That may be why Revell’s rendering of the S-II is so poor—it’s clear, from the paint scheme and other aspects of the model, that they were working from very early iterations of the Saturn V stack, and perhaps they didn’t get very long to look at the production S-II.

The main body of the Revell S-II comes in three parts—one piece for the forward skirt and the dome of the LH2 tank; one piece for the aft skirt, thrust structure and rear dome of the LOX tank; and a printed styrene sheet to be rolled into a cylinder to form the outer wall of the combined tanks.

The first problem with the forward part is a familiar one, if you’ve been following this build log—the locating strips inside the skirt, which engage with a gap in the flanges of the S-IVB interstage above, are misaligned, and need to be shifted so that the S-II is correctly aligned within the Saturn V stack. Unfortunately, the two features of the forward part that allow its orientation to be checked are in disagreement with each other, too—the notch that marks the location of the service tunnel is in the wrong position relative to the vent tubing on top of the LH2 tank. As described in my previous post in this build log, I chose to move the locating strips 11/16″ (17 mm)  to the right so as to get the service tunnel in the right place, and then went on to fill and smooth the circular depression that is the locating point for the vent tubing, which I’ll position correctly later.

Revell 1/96 S-II locating strips
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I also removed the raised edges of the fifteen gores into which the kit divides the tank dome, and replaced them with the correct number—twelve.

Next, there’s the problem of the appearance of the tank dome. The Revell kit has an odd annular structure surrounding the dome, which doesn’t appear in David Weeks’s excellent Saturn V drawings set. It turns out to be difficult to check against reality, because finding an image of the front end of a complete S-II ready for launch is remarkably difficult. They were generally moved around with something called the Forward Hoisting Frame Assembly attached to the top end (there are some nice images of that in action over at Heroic Relics), which completely obscured the LH2 tank dome. And when the Saturn V was being stacked, the photographic views show the underside of the S-IVB being lowered into position, rather than a top view of the S-II. Two of the three surviving S-IIs on display have the Forward Hoisting Frame still attached, leaving the one at the Kennedy Space Center providing the only clear view. It’s a late model, from the cancelled Apollo 18 mission, by which time the method of insulating the LH2 tank had changed, but it’s the best I can find. There’s no structural ring around the tank dome. (That said, displayed Saturn V stages often omit components, like the S-II heat shield, which were added only late in the stacking process.) I suspect Revell have mistakenly moulded in a removable work platform or handling ring, but unfortunately it’s impossible to remove without having to scratch-build a new tank dome.

New Ware Saturn V Detail KitOne thing I could fix is the fact that the stringers on the kit’s front skirt extend too far back. On the real thing, they disappeared into an odd raised external cuff of insulation surrounding the top of the LH2 tank. So I took my measurements off David Weeks’s plans, created a demarcation line around the forward skirt using Dymo Tape, chiselled and sanded to remove the offending parts of the moulded stringers, and then created the appearance of the insulation by wrapping with a couple of strips of styrene sheet. While I was at it, I removed stringers from a few more areas, so that I could later add New Ware’s photoetched details (a personnel hatch, LH2 vent valves, and telemetry antennae). Here’s what I ended up with:

Revell S-II fore 2
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Finally, a puzzle—the right colour for the tank insulation. Again the lack of contemporary colour photographs makes it difficult to know. The material covering the Kennedy Space Center S-II tank has aged to a shade of brown, but the fresh finish is generally described as having been yellow. Many modellers use a zinc chromate yellow-green finish, which was widely applied as an initial coat to protect the metalwork of Saturn V components, and which was certainly applied to the bare external metal of the fuel tanks. However, David Weeks’s drawings contain this piece of information:

Exterior of LH2 tank dome is covered with insulation and is painted FS 33558 Orange-yellow.

That’d be handy, except for the fact that there is no Federal Standard 33558 colour. There is, however, an FS 33538 orange-yellow, and I assume that’s what was meant. I used the Luftwaffe’s RLM 04 Gelb, which appears to be a close match.

If the front assembly is merely inaccurate, the rear assembly is a disaster. Really, Revell should have moulded this in at least two parts—the aft skirt and tank dome; the hollow conical thrust structure and cruciform engine support. Again, there’s nothing short of massive scratch building that can fix the unrealistic wall within the thrust structure, or the fact the cruciform is plastered on to the tank dome, rather than standing free.

The stringers on the aft skirt extend too far forward, so again there was a need for Dymo Tape, chisel and sandpaper to trim them back to their correct extent.

And the aft skirt should also bear a number of fairings protecting various bits of prominent piping—Revell manage to place a few of these, but of the wrong size, shape and position. I can replace the kit parts with more realistic resin parts from New Ware, but first I needed to get rid of the attachment points for Revell’s aberrant LH2 feed line fairings (only one of which aligns with the pipe on the thrust structure it’s supposed to be supplying), and fill the gap left by Revell’s LOX vent fairing.

For reference, here’s the offending item in its raw state:

Revell S-II aft 1
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Having first trimmed off the forward part of the stringers, I then applied myself to getting rid of the raised fairing attachment points. I protected the stringers on either side with Dymo Tape, then used a razor saw and a 2mm chisel to remove the offending part and restore the gap between the stringers.

Revell S-II aft 2
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Revell S-II aft 3
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Revell S-II aft 4
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The vent fairing gap was repaired with white filler, and the missing stringers rebuilt with 1mm styrene strip.

The thrust structure in the real world bore a number of control packages, which are supplied in resin by New Ware. Unfortunately, the Revell thrust structure has one little moulded package in place (at the left side of the image above, in partial shadow), which bears scant resemblance to anything in the real world. It’s also impossible to fully remove without leaving a hole in the thrust structure.

Saturn V axesAfter a bit of pondering, I decided to rotate the entire kit part through 90 degrees anti-clockwise (when looking down from above the Saturn V). This moved the remnant of the unrealistic package from a location next to the A-quadrant engine to the same position in the B quadrant, where it can be almost completely concealed under an engine actuator assembly and an electrical system assembly from the New Ware detail set.

All that was required to achieve this rotation was to fill and sand the locating slot for the service tunnel, and to remove the (in any case unrealistic) attachment points for the central engine, which needed to be counter-rotated through 90 degrees to restore its correct alignment with the rest of the stage. After all I’d already done to this kit part, that was a completely trivial task.

Then I used a grinder to remove the spurious moulded pipework that bedecks Revell’s version of the rear tank dome (just achievable, with care—the plastic was so thin in places that it was translucent by the time I’d finished). I added my own pipework using styrene rod—the LOX fill line, and the LH2 feed for the centre engine, both of which had been omitted by Revell. Then, with the orientation of the aft skirt pinned down, I was able to do a final bit of chiseling to make space for the fairings, umbilical connections and the new position for the service tunnel.

Here’s the final item, still some way from being entirely accurate, but a great deal better than I started with:

Revell S-II aft 5
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The correct colour for the thrust structure was another problem. Again, photographs of the final assembly are rare, and apparently restricted to the S-II stages of Apollo 4 and Apollo 6. The Apollo 6 S-II thrust structure looks sort of white-ish in the NASA image. A good quality photo at Drew Ex Machina (scroll to about halfway down the post) shows the S-II of Apollo 4 with a metallic yellow-green thrust structure. The thrust structure of the very early S-II displayed at Huntsville is flat green, while the late models at Johnson and Kennedy are white.

Essentially, then, I’ve scant idea what colour I should use to realistically depict the SA-506 launch vehicle of Apollo 11. In the end, I mixed up a pleasing yellow-green shade using Tamiya Cockpit Green and Titanium Gold, which ended up about halfway between Apollo 4 and Huntsville*.

The pre-printed styrene sheet that connects the fore and aft skirts was only a little problematic. As with the S-IVB stage, I turned it inside-out so that I could paint it uniformly white and then apply New Ware’s decals. It’s supposed to be held in shape by pins on the service tunnel assembly, but that would leave an exposed edge visible. So (again, as with S-IVB) I glued it together and filled the locating holes, so that I could completely cover the edge with the service tunnel part. At this point, I discovered that aligning the locating holes properly resulted in a part that was very slightly too small to fit on to either the fore or aft skirt. So I pried it gently apart, and reassembled with holes misaligned by a half millimetre or so.

Revell S-II styrene
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Finally, the whole thing fitted together, and I was able to start placing New Ware’s resin and photoetch details.

Revell S-II assembly 1
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Revell S-II assembly 2
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Revell S-II assembly 3
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I’ll pick up the story from there, next time.


* While I was at it, I revisited the thrust structure of the S-IVB stage, which I’d previously left with a greenish metallic tint that looked right in some lights and very wrong in others. The real colour for this structure seems to have been about as variable as that for the S-II. I’m slightly more satisfied with the Tamiya recoat.

Revised S-IVB thrust structure colour
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Tamiya 1/48 P-47D Thunderbolt “Razorback”: Part 3

At the end of my previous post in this build log, I’d got the main body of the aircraft ready for final weathering and the placement of details like the propeller, external fuel tanks, undercarriage and guns.

The propeller is the Hamilton propeller (and associated decals) that comes with the kit, despite the fact it’s not required for either of the aircraft the kit instructions depict. (Thanks for that, Tamiya.) It has a red hub, because the aircraft belonged to ‘A’ Flight of 135 Sq. RAF, who gave their ‘A’ Flight aircraft red hubs, and their ‘B’ Flight aircraft blue hubs.

The external fuel tanks were filched from another kit, Tamiya’s P-47M—I wanted the big 150-gallon (US), rather than the smaller options available with the P-47D kit. The undercarriage was detailed with more Eduard photoetch parts and placards, and a set of resin wheels from Squadron.

They ended up looking like this:

Tamiya P-47D accessories
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I went on to weather the propeller slightly, with gentle metallic dry-brushing along the leading edges to simulate paint wear, and some pale LifeColor Liquid Pigment to the rear surfaces. (Real propellers are counter-intuitively dirtier on the back than on the front—the low pressure airflow across the front surface keeps dirt away from the propeller blade, while the high pressure behind concentrates the airflow and grime.)

I used the Tamiya decals for the fuel cap and label on the external tanks, and immediately regretted the label—it’s quite clearly marked as being for a 75-gallon tank. I went on to dull down the bright metal of the tanks a little—the real items were stored in heaps, sometimes outdoors, so they wouldn’t retain that factory-fresh look for long. And, during the weathering process, I decided I rather not have the labels than have the wrong labels, so they ended up in the bin.

With the tanks fitted to the wing pylons, I had one last detail to add to them. Because of worries about a dropped tank flipping in the airflow and striking the rear edge of the wing, the wing pylons were equipped with spring-loaded fork arms. These were deployed to pressed down on the rear of the tanks, and then they snapped up to a stowed position along the back of the pylon after the tank was released. The Tamiya kit provides these in the stowed position, as part of the pylon moulding. I’d previously removed these, and now I was able to add an Eduard photoetch part to depict the fork arms in their deployed positions. (I’m not convinced the Eduard arms are the right length, when compared to photographs of the real thing, but they were acceptable.)

Tamiya P-47D drop tank with Eduard spring fork arm
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The guns mounted in the wings fired through metal blast tubes. While a photo of 135 Squadron Thunderbolts exists showing the blast tubes painted white to match the SEAC white stripe on the wing, this seems to have been taken very soon after the SEAC markings were first applied.

135 Squadron Thunderbolts
Click to enlarge (You can just make out the spring-loaded fork arm on the drop tank, too)
© Imperial War Museum (CF 201)

I have photographs from later in the war, like the one below from my father’s photo album, which show bare metal tubes—I suspect the paint flaked off the stainless steel tubes fairly quickly.

135 Squadron RAF, 1945
Click to enlarge (Note the casually placed bomb)

Once the blast tubes were in place, I added a little smoke staining to the white SEAC stripe. I concentrated this on the underside, streaming back from the cartridge ejection chutes, and around the muzzles of the two outermost guns, which open almost flush with the wing edge. Some modellers depict four matched, parallel streams of smoke-staining on the upper wing, behind the guns, but this makes little sense when the gun muzzles protrude beyond the wing leading edge. The air stream crossing the upper wing is ascending as it crosses the gun muzzles, and will carry smoke in an arc above the wing, rather than across its surface. Photographs of the real thing generally show minimal staining of the upper wing, for the same reason the front of the propeller tends to stay clean.

Then a little weathering to the wing roots and the fuselage on either side of the cockpit, again with some metallic dry brushing to simulate paint damage. A few flecks of silver around the edges of panels that would be frequently removed (engine cowling, guns) and along the wing leading edges behind the propeller. And then some pale grubbiness at the wing roots and behind the gun panels, where the ground crew would have walked most frequently.

The last touch was to add a strand of stretched sprue to simulate the radio antenna.


The final model is as close as I can get to the appearance of HB981 on the morning of 2nd May 1945, when she took off from Akyab Main to perform “cab rank” duties for the Operation Dracula landings at Rangoon. (That is, the aircraft would loiter above the landing zone, using fuel from their external tanks, so that they could be called in at short notice to strafe any Japanese positions resisting the landing.) But instead of carrying on south with the rest of the 135 Squadron aircraft deployed that morning, HB981 lost power on take-off and ground-looped off the end of the runway, tearing off both wings in the process. The pilot (my father) hopped out of the cockpit unscathed, and then hopped back in again to retrieve his parachute (it was a chargeable offence to lose a parachute), before walking back to the end of the runway and having a seat (on the parachute) while he waited for a vehicle to come and get him.

Soon afterwards, he was photographed standing on the wreckage. The photograph then had a hectic life of its own, sustaining a lot of surface damage before being accidentally torn in half. My father then seems to have rephotographed the torn halves, before adding the picture to his wartime photo album, marked “My Crash”.

Crash of HB981, May 1945
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His crash even made it into the textbooks. In Thunderbolt: A Documentary History Of The Republic P-47, Roger Freeman narrates the story with some amusement (p.77):

Roger Freeman, Thunderbolt: A Documentary History Of The Republic P-47, p77
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The squadron number is wrong (135 didn’t renumber to 615 until later in the war), my father’s name is spelt wrongly (a common error) and the story has grown a little in the telling.

But here’s what HB981 would have looked like, I think, before it got so dramatically bent.

Tamiya 1/48 P-47D "Razorback" (5)
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Tamiya 1/48 P-47D "Razorback" (3)
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Tamiya 1/48 P-47D "Razorback" (1)
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Tamiya 1/48 P-47D "Razorback" (4)
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Tamiya 1/48 P-47D "Razorback" (2)
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Tamiya 1/48 P-47D "Razorback" (7)
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Tamiya 1/48 P-47D "Razorback" (6)
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Tamiya 1/48 P-47D "Razorback" (8)
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And finally, a comparison with the Hurricane IIC I built earlier, showing what a brute the Thunderbolt was in comparison, and why RAF pilots, used to Hurricanes and Spitfires, claimed that the easiest way to avoid enemy fire in a Thunderbolt was to get out of your harness and run around the cockpit:

Comparison of Thunderbolt & Hurricane
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Tamiya 1/48 P-47D Thunderbolt “Razorback”: Part 2

So last time I had completed priming, and had masked off the SEAC white identification stripes.

The next task was to apply the camouflage colours of the Temperate Land Scheme—Medium Sea Grey undersides, and an RAF standard pattern of Dark Earth and Dark Green above. It’s always a puzzle how sharp-edged the camouflage patterns should be. Some patterns were reputedly applied using large paint masks, and so could be expected to be extremely sharp-edged at 1/48 scale. On the other hand, if camouflage was applied free-hand with a spray gun, one could expect to see softer edges, even at 1/48 scale. Looking at contemporary photographs wasn’t much help—some of the patterns on RAF Thunderbolts seemed to be very sharply defined, while others were very diffuse. So I decided I’d try for a softer edge by placing my masking a millimetre or so above the surface of the model, in an effort to simulate the effects of a free-hand spray job.

After painting the underside, I applied Dark Earth to the upper parts, and then laid on paper masks supported by thin rolls of Blu Tack. After an immense amount of fussing around getting the paper edges a reasonably uniform distance from the surface of the model, I sprayed on Dark Green. I had to keep reminding myself to keep the spray as much as possible at right angles to the edges of the masks—the last thing I wanted was to spray under the mask and get a thick line of pooled paint along the edge of the Blu Tack.

Masking Tamiya 1/48 Thunderbolt for camouflage
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But this technique certainly removes a lot of the anxieties about paint leaking under the masking by capillary action. Except, of course, for my white SEAC stripes, with their closely applied masking tape—the white would show up any masking leaks all too noticeably. So there was the customary flicker of anxiety as I started to peel off all the layers of paper and Blu Tack and tape. But it worked out pretty well—a couple of tiny trickles along a couple of panel lines were swiftly removed using a little gentle pressure from a wooden cocktail stick, which didn’t disturb the underlying white paint. Then the whole thing was coated with gloss varnish, ready for the decals.

Tamiya 1/48 Thunderbolt, SEAC colours
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SEAC markings are surprisingly difficult to come by—those unobtrusive little Dull Blue and Light Blue roundels seem to be unpopular with model builders. I’ve previously had an unfortunate experience with a rather elderly set of SEAC decals, bought on eBay, which leaked some unpleasant gunk on to the paintwork while simultaneously refusing to bed down properly. But this time I was well served by Xtradecal’s sheet X48115—variously called “P-47D Thunderbolt in RAF/SEAC Service” or “Yanks with Roundels Part 4”. This not only gave me the roundels and flashes I needed, but as a bonus had the tail serial number for HB982, the aircraft immediately after mine in the RAF code sequence. With a “1” stolen from another set of codes, I was able to assemble the serial number I wanted using only two decals, rather than going through the usual performance of teasing five individual characters into alignment.

The WK-H squadron letters for this aircraft posed another. The official Temperate Land Scheme required code letters to be marked in Sky—a sort of duck-egg green shade. However, according to Geoff Thomas’s book, squadrons tended to mix their own paint from Dull Blue and White, “the resulting colours varying from Deep Sky to light grey-blue”. I’ve yet to find a colour photograph showing this, and looking at black and white photographs is of course no help at all. Here’s a 135 Squadron aircraft from a little earlier in the war:

135 squadron Thunderbolts
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© Imperial War Museum (CF 1242)

Are those code letters pale grey-blue or duck-egg green?

The problem was resolved for me, though not to my particular satisfaction, by how difficult it was to obtain RAF letters of the right size (18″) in any shade but Sky. Although pale blue letters are available for particular aircraft on the Xtradecal sheet, they didn’t match what I needed, and I couldn’t track down any white letters of the right size, which I could have tinted. A truly dedicated model maker would have produced his own stencils and sprayed the letters on, or printed them on to white decal backing and cut them out, and I actively considered those options for a while, before deciding that whatever I did, it would not be a match for the unknown original appearance. So I went with the standard Temperate Land Scheme—the letters I used are from Fantasy Printshop.

Tamiya 1/48 Thunderbolt, SEAC colours and markings
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I added the various small stencils for fuel fillers and electrical connections supplied with the Tamiya decal sheet. I couldn’t find any photographs suggesting that a red “No Step” panel on the inboard flaps were used in RAF SEAC aircraft, so I replaced the panel provided on the Tamiya decal sheet with a plain stencil from my decal cache.

Once the decals had bedded in and dried thoroughly, I added another coat of gloss varnish and started marking up the (many, many) panel lines. As with previous kits, I used Lifecolor’s Liquid Pigment for this. It settles neatly into the engraved lines of the kit, and any excess can be removed (even when dry) with Lifecolor’s removal fluid. Careful wiping of partially removed pigment produces a nice preliminary weathering of the aircraft’s surface. The main trick to using this stuff is to keep shaking the bottle—it settles out very quickly, so the black liner will slowly turn blue if you don’t keep remixing the pigment.

Once that had dried, I applied a couple of coats of matt varnish, ready for final weathering and the addition of final bits and pieces like the undercarriage, propeller, guns and external fuel tanks.

Tamiya 1/48 Thunderbolt, SEAC colours and markings, panel lines
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Tamiya 1/48 Thunderbolt, SEAC colours and markings, panel lines underside
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And that’s where I’ll pick up next time.

Tamiya 1/48 P-47D Thunderbolt “Razorback”: Part 1

Tamiya 1/48 P-47D RazorbackI’m using the Tamiya kit to model a specific aircraft, again. This is going to be a Republic P-47D-22-RE Thunderbolt, on the complement of 135 Squadron RAF in Burma from April to May 1945. Its American serial number was 42-25818, with a British serial of HB981. It was what the RAF called a “Thunderbolt I”—what’s commonly referred to as a “razorback”, to distinguish it from the later “bubbletop” models, which the RAF designated the “Thunderbolt II”.

It met its end at Akyab airfield, damaged beyond repair, on 2 May 1945, when it lost power on take-off, crashing and ground-looping some distance beyond the end of the runway. The squadron Operation Record Book has a laconic record of the event:

135 Squadron Operation Record book 2/5/45
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I’ll fill in a bit more detail as we go along.

The Tamiya kit is nominally a P-47D-20, but includes the parts I needed to make the one big change necessary to turn it into a P-47D-22 version—a larger propeller. The RE code indicates that my aeroplane was built at the factory in Farmingdale, Long Island, which fitted Hamilton Standard propellers to their block 22 aircraft. Despite the fact it’s not called for in the kit assembly instructions, a Hamilton propeller is actually included on the kit sprue, with appropriate maker’s marks on the decal sheet, too.

This is my first Tamiya kit, and I have to say I’m seriously impressed. Coming to it after my recent forays into ancient Revell, Airfix and Lindberg toolings, it’s a joy to work with parts that just fit together properly, and mouldings that place the gates in sensible places (rather than slap in the middle of a complicated and highly visible surface).

I added a couple of photoetched sets from Eduard—their P-47D-20 detailing kit, and their P-47D placards. There’s a bit of overlap between these two sets, but they each included something I wanted. I also needed to track down a 1/48 scale Sutton harness—the RAF reportedly (though there’s some debate) replaced the American-style harness in American aircraft with their own standard type. I settled on a “fabric” version from HGW Models, which looked promising but caused me a fair number of problems.

The Tamiya cockpit is nicely detailed, and fits together perfectly. I slightly vandalized it by accidentally setting my airbrush at too high an operating pressure for my Alclad primer, lending the surfaces a slightly pebble-dashed appearance that shows up rather too well in the detailed photos that follow, particularly the bright metal areas. Trying to strip off a laquer layer seemed like too dangerous an enterprise, and the result will anyway be much less visible inside the assembled cockpit, when the light necessarily comes from within a pretty narrow angle to the viewing direction.

I added the Eduard cockpit placards and instrument panel, and a selection of levers and nobs. The HGW harness seems to be made of some sort of stretchy neoprene, admirably detailed, and supposedly thin enough to thread through the various photoetched buckles provided. It comes on a white backing paper. When I tried to remove this, a couple of straps separated into sections; when I tried leaving it in place, it proved too thick to thread through the buckles properly. Eventually I used parts of two harness sets to produce one slightly bodged final result.

Tamiya P-47D cockpit 1
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Tamiya P-47D cockpit 2
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Tamiya P-47D cockpit 3
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I made one modification to the Eduard detail—revising the throttle lever with a couple of plastic strips to produce the brown-and-white object that looks a little like an ice-lolly sticking up from the left side of the cockpit. I’m not entirely sure about this. The P-47 throttle lever went through at least three iterations during production, shown below in details taken from various pilot’s manuals.

P-47D quadrant 1

P-47D quadrant 2

P-47D quadrant 3

The reference works I have are inconsistent with each other, and the manuals sometimes show more than one style of quadrant. Eventually I made a “best guess” to model the middle illustration above, with a large vertical throttle handle supporting a water-injection switch on its top.

Next, the engine. The Hurricanes I’ve been modelling had their engines decently concealed, but the Thunderbolt had a fair part of its complicated air-cooled radial engine on display. The Tamiya kit provides parts for the front half of the engine (all that’s visible in an intact aircraft), to which I added a photoetched ignition harness from the Eduard detailing set. Here it is, during a trial fit, which also demonstrates the lovely moulding Tamiya produces:

Tamiya Pratt & Whitney with Eduard armature
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It’s a challenging object, comprising 36 cables, each of which has to be connected to the front or back of one of the Pratt & Whitney R-2800’s eighteen cylinders.

That came after painting, weathering and detailing the kit engine. Here’s the final assembly, with ignition harness in place:

Tamiya Pratt & Whitney completed 2
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Tamiya Pratt & Whitney completed 1
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Notice the tiny Pratt & Whitney eagle logo on the front, provided by Eduard.

Then it was a matter of masking and priming the aircraft fuselage. I put the undercarriage covers in place with Blu Tack, to mask the wheel wells and prepare them for the underside paint. The cowling has a nice locating mechanism that means it’s easy to paint it separately and put it in place later. I’m also modelling this aircraft with flaps down, so they’re being primed and painted separately.

P-47 primer 1
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P-47 primer 2
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The white primer is chosen because this aircraft sported SEAC stripes—white identification markings on cowling, wings and tail adopted within the South East Asia Command area in 1945. I’ve left my primer a little thin—I didn’t want to layer the stuff on and obscure detail, and any slight variation in the lightness of the overlying paintwork will be compatible with the weathered appearance that’s evident in photographs. I’ve also sprayed the area of the SEAC stripes with a final coat of matt white, which I’ll then mask to protect it from the application of later camouflage paint. That’s a reversal of the order in which this paint would actually have been applied, but again I want to preserve surface detail by avoiding having to apply multiple layers of white on top of dark camouflage colours.

Cover of Royal Air Force ThunderboltsThere’s a bit of a problem with the SEAC stripes for this aeroplane. According to Geoff Thomas’s excellent reference book Royal Air Force Thunderbolts, HB981 was part of a batch delivered between 12 March and 12 May 1944. But it doesn’t appear in 135 Squadron’s Operations Record until 4 April 1945, despite the fact that from the end of the previous year they were operating other HB and HD aircraft delivered in the same time frame. Where had HB981 been prior to its arrival at 135 Squadron? Maybe with another squadron, or perhaps in store, ready to be dispensed as a replacement aircraft. James J. Halley’s history of the H* serials doesn’t list HB981 anywhere else but with 135 Sq., but there are often gaps in the record.

Cover of Royal Air Force Aircraft HA100-HZ999Why is any of this relevant to the SEAC stripes? Because they were first used at the very end of 1944, when the original Instruction stipulated that stripes should span the whole chord of the vertical and horizontal stabilizers. After a protest that this extra layer of paint might interfere with the operation of the control surfaces, a new Instruction was issued in March 1945, stating that the tail stripes should not impinge on the rudder or elevators.

SEAC stripes (from Royal Air Force Thunderbolts, Geoff Thomas)
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Full-chord SEAC stripes

If HB981 had come straight from storage, it would have been painted up with the later pattern of SEAC stripes; but if it had been in operation earlier in the year, it might still sport the full-chord stripes on its tail. (Thomas says that some aircraft had their tail markings stripped and reapplied, but there are plenty of photographs showing full-chord stripes still in place, right up to the end of the war.)

79 Sq RAF, Meiktila, July 1945
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79 Sq. RAF, Meiktila, July 1945. NV-B (third from right) still sports the full-chord SEAC tail stripe. (Photo R.C.B. Ashworth)

So, in the absence of contrary evidence, I decided to give HB981 the later pattern of stripes. I masked off the relevant areas, and then applied another thin layer of white around the edges of the masks, to try to ensure that the subsequent layers of camouflage paint don’t leak into the white areas.

P-47 SEAC masking
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And that’s where I’ll pick up this build log, next time.

Lindberg 1/96 Moon Ship (Revised)

This is a rickety old kit, first issued in 1958 by Lindberg. The version I’m building is a nostalgic reissue by Round2. During its sixty-year history, it has undergone various metamorphoses: shifting its supposed scale between 1:96 and 1:200; changing its name from U.S. Moon Ship (1958) to Star Probe Space Shuttle (1980s) to Lunar Lander (1993) and then back to U.S. Moon Ship (2013); and being issued by at least three different companies—Lindberg, Glencoe and Round2.

Multiple box art for Linberg Moon Ship
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My interest stems from the fact it was based on a real design by Wernher von Braun, dating from the early 1950s, for a projected flight around the moon. A diagram of von Braun’s original conception appeared in the book Across The Space Frontier (1952), which I’ve previously reviewed. Von Braun’s plan involved assembling the 80-foot-long craft in orbit.

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Chesley Bonestell produced a painting of the craft for a Collier’s magazine article published in March 1952, which was reproduced in Across The Space Frontier.

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For reasons unknown, Lindberg decided to stick a set of landing legs on it, and to remove the crew access module from the personnel sphere, replacing it with an oddly sculpted but apparently functionless base. Even if this thing could land on the moon, the crew would be trapped in their quarters at the top of the stack, with no way to get out, let alone down to the surface.Detail of box art, Lindberg Moon Ship

Lindberg also added some strange red domes to cover the portholes, and discarded the hydrogen peroxide torus at the base of the stack.

So I wanted to migrate this lunatic Lindberg confection some way back towards von Braun’s original idea.

The first thing I did was chop the legs off.

Framework for Lindberg Moon Ship
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Framework for Lindberg Moon Ship, minus legs
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Then I sawed the sculpted base off the personnel module, and replaced it with a scratch-built airlock, built from 20mm pipe and styrene card.

Modified crew compartment, Lindberg Moon Ship
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Finally (and miraculously) I discovered that two inches is a standard diameter for the sort of large curtain rings that slides along a pole, and that a two-inch ring fitted neatly into the base of the model framework. All I had to do was remove the eyelet from the ring, and I had my peroxide tank!

Two-inch curtain ring
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Two-inch curtain ring, modified for peroxide tank
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The strange red plastic domes were discarded, and the strange red plastic rocket nozzles were primed and painted.

Clear parts, Lindberg Moon Ship
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Then it was just a matter of assembling the small number of parts, and shifting the kit’s single nitrogen tank slightly to accommodate the larger volume of the airlock. I discarded or repurposed most of Lindberg’s selection of decals, which didn’t seem to make much sense, and put together a set of markings from my decal stash that I felt fitted the period better—including a 48-star American flag and some late-war aircraft lettering.

Lindberg Moon Ship, modified to von Braun concept
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It’s not a perfect reproduction of von Braun’s concept, but at least it has most of the right parts in approximately the right order.

I wanted to show the spacecraft “in flight”, and I wanted to have an astronaut performing some sort of EVA, as in Bonestell’s painting. So I found an old Airfix stand to attach the craft to, and I modified the legs of one of the kit’s standing astronaut figures to look more like someone working in free-fall. A length of 5-amp fuse wire (remember fuse wire?) provided the EVA tether.

Here’s the final result:

Moon Ship 12
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Moon Ship 13
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Moon Ship 9
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Moon Ship 4
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Moon Ship 10
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Moon Ship 11
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Moon Ship 8
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Revell 1/96 Saturn V: S-IVB Aft Interstage

Having finished building the S-IVB third stage of my Saturn V, I moved on to the S-IVB Aft Interstage—a conical support structure that separated the 6.6m-diameter S-IVB above from the 10-m diameter S-II second stage below. The real thing was assembled into the Saturn V stack as part of the S-IVB, but after launch it remained attached to the spent S-II stage when the S-IVB engine fired. (At the moment of separation of the two stages, the interstage fired four solid fuel retro-rockets that nudged the S-II backwards away from the S-IVB.)

S-IVB and aft interstage
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The S-IVB and its aft interstage (from the Saturn V Flight Manual: AS 503 (19MB pdf)

So you’d think a “building” instalment that involves finishing a single kit part wouldn’t be a problem. But you’d be wrong. The S-IVB Aft Interstage strikes fear into the heart of anyone who has ever painted a Saturn V model kit, because it involves painting horizontal black/white separations around the curve of a ribbed cone. The potential for paint masking to go horribly wrong is high.

There are other, Revell-specific problems. The first is (as with every stage of this model) just getting the orientation of the interstage right. The basic part is symmetrical—a simple conic frustum with four retro-rocket fairings evenly placed around it. But it needs to be painted with a pattern that is strongly asymmetrical—four quadrants each with their own black/white scheme. So its orientation needs to be judged from how it fits to the parts above and below.

The upper end of the interstage contains two locating studs intended to fit between flanges at the base of the S-IVB stage.

Original locator studs on Revell 1/96 S-IVB aft interstage
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But there are a lot of flanges, the kit instruction booklet contains no diagram of the intended fit, and none of the possible orientations make any sense when compared to photographs of the real launch vehicle.

All but one of the slots between flanges are associated with locating points for kit parts to be applied to the S-IVB itself. The remaining slot is a little wider than the others, so it seems likely that it was intended to engage with the wider stud on the aft interstage.

Revell 1/96 S-IVB locator slot
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After a little deliberation, I sanded off both studs, with the intention of placing one of my own later, to engage with this slot on the S-IVB.

The base of the kit interstage has flanges of its own, with a broad locating gap intended to engage with a pair of locating strips moulded into the forward skirt of the S-II kit part. So that looks promising. There are two visible landmarks on the kit’s S-II forward skirt—a notch that marks the location of the service tunnel, and a circular depression that marks the location of the liquid hydrogen vent pipes. Unfortunately, these two landmarks aren’t even properly aligned with each other, and neither of them is in a correct relationship with the axes of the interstage as defined by its retro-rocket fairings.

Revell 1/96 Saturn V - S-II forward skirt
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S-II forward skirt

After checking with David Weeks’s jawdroppingly lovely Saturn V technical drawings, I sanded off the locating strips of my S-II forward skirt, and added styrene replacements 11/16″ (17 mm) to the right (as viewed from inside the skirt). This brings the S-II service tunnel into an appropriate orientation with the retro-rockets of the interstage, and I can deal with the LH2 vents as a separate issue when I get to that stage.

OK. With the relative orientation of the interstage and S-II nailed down, I now knew which quadrant of the interstage was which. Before I lost track of this, I scribed in a surface detail missing from the kit—a personnel access hatch that allowed workers to enter the interstage space. After measuring from Weeks’s drawings, I stuck Dymo Tape in place to act as a guide for my scribing tool. (Does anyone use Dymo Tape for its original purpose any more?)

Revell 1/96 Saturn V - scribing hatch on S-IVB aft interstage
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Next I needed to think about the kit’s depiction of the retro-rocket fairings, which isn’t great. New Ware’s detailing set provides a set of resin replacement parts, which are slimmer than the kit detail, and include a moulded depiction of the detachable front covers of the fairings.

Revell 1/96 Saturn V - retrorocket fairing on S-IVB aft interstage + resin replacements
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However, I would need to chisel out the moulded kit detail and refill smoothly around the resin replacements. After a bit of consideration, I decided not to risk the potential carnage I could wreak during such a replacement. Instead, I compromised by adding the front covers to the existing kit moulding, using epoxy resin and a little bit of masking tape.

Revell 1/96 Saturn V - adding cover to retrorocket fairing on S-IVB aft interstage
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Adding the resin to the kit fairing
Revell 1/96 Saturn V - cover added to retrorocket fairing on S-IVB aft interstage
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The final result

On, then, to the paint masking. Having sworn off using Bare-Metal Foil after my struggle with it while building the Instrument Unit, I suddenly became enamoured of it again. I couldn’t think of any better way to mask the corrugated surface created by the interstage stringers. So for the arc of the model that requires a black/white horizontal demarcation, I measured along the length of each stringer with a precut length of styrene strip, marked with a pencil, and then masked with an individually patch of Bare-Metal Foil, carefully bedded into the space on either side of the stringer using a tooth-pick and a cotton bud.

Revell 1/96 Saturn V - paint masking S-IVB aft interstage
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The interstage was also marked with contrasting sway targets—little 2×2 checkerboards that allowed launchpad cameras to track any swaying of the launch vehicle. I masked these off, too, but ran into a couple of problems. The first is that the Revell kit’s stringers are notoriously overscale, and if I tried to stick to the correct size for the sway targets, they were just too distorted by the relatively large stringers and didn’t look square. So I ended up making them a little oversize, copying the dimensions of the sway target decals provided with the kit. The other problem is that David Weeks’s otherwise excellent technical drawings show two very slightly different positions for the sway target in quadrant B of the interstage—I didn’t notice this until after I’d masked and painted, and it looks like I chose the wrong diagram to follow.

The Bare-Metal Foil was as hard as ever to remove, and again needed a little white spirit to remove a dark residue from the white paintwork it had masked—but I got away without significant leaks, which was a major triumph.

Revell 1/96 Saturn V - S-IVB aft interstage (1)
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Revell 1/96 Saturn V - S-IVB aft interstage (2)
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With the interstage properly coloured, I put the S-IVB in place, correctly aligned, and made a light pencil mark where I needed to add a new locating stud to the interstage to register the flanges of the S-IVB stage correctly.

Revell 1/96 Saturn V - S-IVB and aft interstage
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Tracing backwards through all the fiddling around to get things lined up, it turns out that the correct location is 1/8″ (3 mm) to the left of the slimmer original stud. So I needed to do this:

Moving locator studs on Revell 1/96 S-IVB aft interstage
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to produce this:

Revised locating stud on Revell 1/96 S-IVB aft interstageAnd that was that. The Saturn V stack grows ever higher, but I’m going to take a break and do something else before I tackle the travesty that is Revell’s S-II stage.

Revell 1/96 Saturn V - Apollo stack, S-IVB and aft interstage
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Revell 1/96 Saturn V: S-IVB Stage

It’s been a while since I made any progress on this kit. Last time, I described building the Spacecraft/Lunar Module Adapter and Instrument Unit assembly. Moving down the launch vehicle, this time I’m building the S-IVB stage, which was the third stage of the Saturn V—the “small” one that pushed the Apollo stack into Earth orbit and then into translunar orbit.

The Revell kit has three parts for the main body of the S-IVB: moulded pieces representing the forward bulkhead and forward skirt; the aft bulkhead, thrust structure and aft skirt; and a printed piece of styrene card to connect the two, representing the hydrogen tank external wall. The styrene card is intended to be wrapped into a cylinder, and held together by a plastic strip representing the systems tunnel, which in the real rocket carried all the electrical connections between the aft and forward skirts—so it handily spans the full length between the two skirts.

Revell 1/96 Saturn V, S-IVB stage basic parts
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There are a few problems with this basic assembly. One is that the styrene sheet is “helpfully” printed with the letters U S A. The only Saturn V S-IVB stage to be lettered in this way was the 500F Facilities Integration Vehicle, a dummy that never flew. (Unfortunately, that’s the Saturn V from which Revell derived the markings for its model, which it has never updated through numerous reissues.) So this needs to be flipped inside-out to conceal these markings. I blocked the locating holes with pieces of styrene card, so that they could be filled and sanded.

Revell 1/96 Saturn V, S-IVB stage styrene inside out
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Another problem is that the moulded locating strips within the forward skirt, which fit into the Instrument Unit above, are (as I reported last time) out of place by about 10º, and need to be relocated so that the SIV-B is correctly aligned with the Apollo stack. The necessary displacement is by a quarter inch (six millimetres), to the right as you look at the inside of the skirt. This moves the systems tunnel of the S-IVB two scale feet to the right of the -Y marker on the Instrument Unit, and the same distance away from the Position II coordinate of the launch vehicle (which faces the launch tower).

Shift in locating strips for Revell 1/96 S-IVB stage
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And finally, the systems tunnel provided in the kit is the wrong shape and size, and needs to be replaced—the replacement part being carefully aligned so that it conceals the seam in the styrene cylinder, above.

New Ware Saturn V Detail KitFor replacement parts, and additional detailing, I’ve been using New Ware’s Saturn V Detail Set. As well as a properly shaped systems tunnel, this also provides replacement and additional parts for various fairings in the aft skirt, and photo-etched parts for the umbilical attachments, fore and aft.

Getting these parts into position requires a degree of chipping away at the moulded stringers in the kit parts, to create space for the new resin and photo-etch parts. I first marked up the parts to be excised with reference to photographs and plans, and by dry-fitting the new parts. The curvature of the kit parts was just sufficient to allow careful paring of one stringer using a sharp blade, without damaging neighbouring stringers. The number of new gaps and new parts began to get a little difficult to keep track of, so I ended up numbering the spaces and parts with a felt pen.

Revell 1/96 Saturn V, S-IVB stage aft skirt marked up for detailing
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Once all the parts that were going to be white on a white background were in place, I placed bits of masking tape to protect areas where parts were going to be attached that have colours that contrasted with the fuselage, then primed the model. The bulkheads, thrust structure and inner skirts were primed with white Alclad, because they were going to have a metallic finish applied. The outer surface was primed with Tamiya white primer, which was also going to be my basic white colour. Here it is with the masking partially in place for the black paintwork on the forward skirt:

Revell 1/96 Saturn V, S-IVB stage partially masked
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Once the black paint was in place, I added four white antenna fairings to the forward skirt, and then gave the whole thing a coat of silk varnish.

While I was doing this, I assembled the J-2 engine. In fact, I assembled six J-2 engines, because the second stage requires five, and I thought I might as well do them all at once. There were problems with the seams where the two halves of each engine bell come together—I thought I’d done a reasonable job of concealing them, but they’re unfortunately still quite visible in some lights, courtesy of the metallic finish.

Revell 1/96 Saturn V, J-2 engines
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The colour of the thrust structure is a bit of a vexed problem. The Revell painting instructions suggest a matt mid-green finish, but the photos I find online, of S-IVB stages on display, suggest a sort of brassy metallic sheen to the green. I ended up applying Alclad brass, with a transparent green Alclad lacquer on top. The end result was a bit of a mixed blessing—looking satisfactory under direct illumination, but too dark a green when it’s in shadow. Here’s the final effect (looking too dark!), with the stage waiting for its final details to be added—the silver metallic Auxiliary Propulsion System modules and umbilical connectors:

Revell 1/96 Saturn V, S-IVB stage awaiting final detailing
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And here’s the thrust structure under direct illumination to show the colour I’d aimed to achieve:

Revell 1/96 S-IVB stage thrust structure
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(In reality, the thrust structure was partially covered by a complex tangle of wires and pipes, but my enthusiasm faltered at the prospect of spending so much time detailing an area that will be hidden inside the final model, most of the time.)

Here’s the completed model, with the Instrument Unit and lower part of the Spacecraft/Lunar Module Adapter attached, which is the way we see it in photographs taken in orbit.

Revell 1/96 Saturn V, S-IVB stage with IU & SLA (1)
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Revell 1/96 Saturn V, S-IVB stage with IU & SLA (2)
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And here’s the kit’s astronaut figure, to give a sense of scale to what we often think of as a “small” rocket stage:

Revell 1/96 Saturn V, S-IVB stage astronaut comparison
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Next time, the S-IVB aft interstage—which despite being just one kit part promises to be a real pain in the neck to model.