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.
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:
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:
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.
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.
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.
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.)
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.
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.)
And here’s the Position II view with the S-IVB aft interstage on top, just to check alignments.
And that’s it for the S-II. Next up, the S-II aft interstage—which (you guessed it) needs considerable modification.
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.
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.
One 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:
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.
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:
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.
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.
After 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:
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.
Finally, the whole thing fitted together, and I was able to start placing New Ware’s resin and photoetch details.
* 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.
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:
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.)
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.
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.
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”.
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.
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:
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.
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.
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:
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.
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.
I’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:
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.
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.
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:
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:
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.
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.
There’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.
Why 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.
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.)
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.
And that’s where I’ll pick up this build log, next time.
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.
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.
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.
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.
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.
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.
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!
The strange red plastic domes were discarded, and the strange red plastic rocket nozzles were primed and painted.
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.
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.
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.)
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.
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.
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.
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?)
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.
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.
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.
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.
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.
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:
to produce this:
And 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.
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.
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.
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).
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.
For 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.
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:
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.
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:
And here’s the thrust structure under direct illumination to show the colour I’d aimed to achieve:
(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.
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:
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.
This kit was first released fifty years ago. It’s a model of a real aircraft, the Wallis WA-116 Agile autogyro, designed by Ken Wallis and built in extremely limited numbers (five!) in 1962. It achieved fame because one aircraft, G-ARZB, was kitted out with some splendid yellow-and-silver livery and simulated weapons for the 1967 James Bond film, You Only Live Twice.
Wallis’s great innovation was to build an autogyro that was stable “hands off”—he used to make demonstration flights while waving his hands and feet around.
But I doubt if even Wallis could fly hands-off while simultaneously firing guns, rockets and flamethrowers, as Sean Connery is depicted doing in the risible box art.
The original 1967 kit had a rather more sedate illustration (“One weapon at a time, Bond!”):
But when it was reissued in the 1990s (the version I have), the kit had lost a couple of springs (of which more later) and had acquired its mad artwork from one of the original movie posters.
The kit lets you build one of two versions of the WA-116—either a drab and basic Army Air Corps test version, or the brightly coloured and heavily armed movie version, code-named “Little Nellie”. Of all the kits sold, I wonder how many ended up in Army Air Corps livery. I’m guessing that figure is very close to zero. Little Nellie is pretty much the whole object of the exercise.
If you want a look at what I’m aiming to reproduce, you can have a walk-round of the aircraft with Major Boothroyd, followed by a brief test flight, in this clip from the film:
So. The first thing to say about this kit is that, by modern standards, it’s not a great tooling. A lot of flash to be trimmed, a lot of ejector-pin marks and sink holes in awkward places, and some parts that don’t really fit together very well. The second thing to say is that the order of assembly seems to have been designed to thwart anyone aiming to get a smooth paint finish. The fuel tank, in particular, clips on in two halves around a previously assembled central mast, which would make it hard to eliminate a visible seam between the two halves. So I free-styled the assembly order a little.
Here’s what I did with the fuel tank. I dry-assembled the rotor mast, put a big wodge of epoxy inside one of the tank halves, then dry-assembled the tank on to the mast and taped it in place until the epoxy dried. Then I disassembled the mast again, leaving me with one section of the mast entirely embedded inside the fuel tank so that I could assemble, fill, sand and paint the tank before adding it to the mast assembly.
I also needed to do something about the forward weapons pods. In the original kit, these were provided with little spring-loaded rockets that could be shot halfway across the room in a satisfying sort of way, although bearing no resemblance to the weapons depicted in the film. The re-issued kit omits the springs, producing a final effect that is both unrealistic and functionless. So I put together some replacement pods using quarter-inch styrene tube and sheet, married to the original supports from the kit parts.
And I lifted an image from a photograph of the original pods to make myself a pair of custom decals for the front of my replacement pods, depicting the weapons cluster in detail that was too fine for me to model convincingly.Now, I’m used to having a few pre-painted bits and pieces of a kit sitting in a pot waiting to be added to the overall assembly. What’s striking about this kit, though, (especially in the order I built it) is that it consists almost entirely of pre-painted bits and pieces. I had to get some bigger pots.
The basic skeleton of the aircraft is a horizontal strut with the tail at one end and the rudder pedals at the other.
Once I got that painted up and decalled, I was able to close the front fairing around it. Once in place, this needed a lot of filling and sanding, and some work on the holes through which the guns protrude, to create the individual fairings visible in the film. But all this work was made a lot easier by not having the mast assembly and fuel tank in place, which is what the assembly instructions required.
Painting the front fairing is a challenge. The scheme is yellow above and silver below, separated by a tapered black and white stripe that also forms a ring around the nose. The stripes are supplied on the decal sheet, with the nose ring in two halves that need to be married together quite precisely. So the position of the decal is critical, and it in turn determines the extent of the areas to be painted, above and below the stripe. While it’s possible to simply make an approximate paint margin and obscure this by applying the decal on top of it, the yellow paint will shine through the semi-transparent white part of the decal—I’ve seen photographs of various builds of this kit in which the yellow paintwork shows through as an irregular discolouration of the white stripes.
After I bit of pondering, I scanned the decal sheet and printed it out on plain paper. Then I cut out the shape of the stripes, and glued them to some masking tape.
Then I cut out the masking tape in the shape of the stripes, and applied it to model. The copy didn’t need to be precise (and you can see from my photo that it wasn’t!)—it just needed to be good enough to establish the position the decal was going to occupy eventually. The decal stripe has a one-millimetre black edge that obscures any minor deviations in the paint line.
By wedging the rear of the front fairing slightly apart with a length of toothpick (visible in the photo), I was also able to drop in my assembled fuel tank to make sure its stripes and paintwork aligned properly with the fairing stripes and paintwork, and then lift it out again for ease of painting.
After painting, I peeled off the masking tape and simply slide the decals up to the edge of the yellow paint, getting a perfect position very quickly—which is always handy when you’re fiddling about with elderly decals. The nose rings needed some radial slits so that they settled smoothly on to the curve of the nose without wrinkling. And the central black disc within the nose rings needs to be painted. I couldn’t see a good way to mask that on a very curved surface, so I did it by hand, carefully following the edge of the inner white ring of the decals.
Then I opened the rear of the front fairing again and slipped the painted fuel tank into its final position, laying on its decals so that they aligned with the existing stripes. And I also added the painted and decalled front weapons pods. So at this stage I had an exotic-looking yellow-and-silver object, resembling some sort of strange wasp.
In the photo, you can see a couple of cables, made from stretched sprue, which I added before I closed the fairing. These are going to be the rudder cables on the final aircraft, but for the time being their aft ends are secured to the tail with a little masking tape.
Now I just had to add all the parts that the instructions had wanted me to add much earlier. The main mast assembly, complete with engine, slotted easily into the top of my pre-prepared fuel tank. The twin pitch/roll rotor control rods can be slipped into their locating holes next to the control column and then pivoted into position (That is, so long as they’ve been test-fitted and the holes enlarged to provide a slightly loose fit before the fairing is closed in place!)
The kit comes with a pilot figure, but since I wanted to build the model with the rotor supports in place, the pilot just looked daft sitting in an aircraft that was obviously not ready to fly, so I omitted him. Without a pilot, the real aircraft sits on its small rear wheel, and only tips forward on to its tricycle undercarriage when the pilot climbs aboard (you can see this happening in the video clip I included above). However, as the kit assembly proceeded the model showed more and more of a tendency to sit on its front wheel, with or without pilot. There aren’t many places to include some extra weight around the tail, but I slipped some short sections of 2mm brass rod into the hollow tubes of the rear flamethrowers, and that was just enough to give the completed model a realistic tail-down posture.
Once all the kit parts were in place, I added rudder actuator levers and attached the rudder control wires, as well as putting in some of the more obvious other cable runs—to the brakes and to the rotor spin-up drive. Along the way, I’d also added some other small details—a seat cushion and lap belt, spark-plug leads, and a support arm for the rotor spin-up drive. The final detail was the pitot tube in the nose, made from 1mm brass rod, with a little vertical 0.5mm support for a low-tech “drift indicator”. In the real aircraft this was a tuft of wool—I added it using a tiny splotch of epoxy which I stretched into a delicate little thread and painted red after it had dried.
Here’s the final product, looking almost disturbingly bright and clean compared to the care-worn Second World War fighters I’ve been building recently:
There are a couple of things I hate about “in-flight” models of piston-engine aircraft. One is when the aircraft appear to be flying without a pilot; the other is a stationary propeller.
Modellers have a couple of ways of dealing with this second problem. One is to simply remove the propeller blades, leaving only the filled and smoothed spinner visible—it’s a well-recognized technique which many feel produces the most realistic appearance. But it always makes me think, Where’s the propeller? I find the complete absence of anything in the space where the propeller should be is a little distracting. I’m also not very keen on the photo-etched “prop-blur” option, which aims to produce a blurred sector for each prop blade, reproducing what we see in photos and movies, but not what we see with the naked eye.
So what I want to see is a transparent disc of the correct propeller colour(s), with the colour density at each radius matching the relative amount of prop blade and empty space at that radius. A while ago I posted a tutorial about this on WW2Aircraft.net; now that I have my own website I thought I’d reproduce it here in a slightly revised version.
Here’s what I do:
1) Mark up and measure the kit propeller at regular intervals starting from the centre of the prop boss.
2) Calculate what proportion of the prop disc is composed of prop blade at each measured radius. Multiplying the radius by 2π gives you the circumference at that radius, and the measured blade width times the number of blades gives you the total amount of prop blade at that radius. Divide the latter by the former, and you have the proportion of the circumference at that radius which is occupied by prop blade. I also calculate a relative density—whichever radius has the maximum proportion, I set that proportion equal to one, and work out the value for all the other radii as a proportion of that. Here’s my little spreadsheet, filled out with data.
3) I open GIMP, and create a colour gradient matching the radial densities I calculated above.
GIMP is an open source image manipulation program, available here. There’s a tutorial on building GIMP gradients here.
In this case for a Luftwaffe prop my base colour is RLM71, and I don’t need to worry about adding tip colours. I can consult William Marshall’s excellent Digital Colour Charts page to find the Red/Green/Blue values corresponding to various paints used by various air forces during the Second World War. So I find that RLM71 corresponds to RGB 82/88/86. The alpha channel (“A” in the GIMP tool) should be set to the densities I calculated above. In this case my prop disc becomes steadily more transparent towards the rim. I add a small dense black region at the extreme left end, which will mark the centre of the prop disc – that’ll make it easy to cut out with a scribing tool, and it will be obscured by the spinner in the final assembly.
4) Having built the gradient, I open a new document in GIMP, making sure to set the resolution in pixels per inch to match my printer. Using my newly created gradient, and the “radial” setting, I draw a circular gradient of the correct radius for my propeller—in this case 24mm.
5) I duplicate this disc a few times, and print out. On this occasion, I’ve used overhead-transparency film—it’s a little thin, but makes the job quicker and easier. I’ve sealed the printed side by airbrushing gloss varnish. I’ve also had success using printable decal film which I then transferred to thicker transparent plastic sheet. In either case, use a cutting compass tool set to the prop radius to cut out the disc (this is where that black centre mark comes in useful).
6) Now remove the blades from the kit propeller, sand the spinner smooth, and divide with a razor saw. Some spinners with rear cut-outs will need filled before sanding. Sometimes it’s easier to just remove the rear of the spinner and replace with a new part fashioned from styrene rod or tube of an appropriate diameter. Glue the rear and front parts of the spinner to the centre of the prop disc.
7) And complete. Here are the prop discs fitted to the Planet Models resin kit of the Blohm & Voss P.170 Schnellbomber. (A bizarre design, with the pilot sitting at the back of the aircraft, which never got off the drawing board in real life.)
There are a couple of disadvantages. I’d say that 1/72 is about the largest scale on which this works—beyond that, the disc are too thin to be realistic. And if your propeller has a white stripe in the safety markings at the tip, you’re probably out of luck unless you have a very expensive printer with white toner.