Once upon a time there was a DC-3 in China that had a really, really bad day at the hands of
some Japanese fighter-bombers. In some desperation, mechanics replaced it's shattered
starboard wing with a replacement from a DC-2, turning the poor DC-3 into what became known
as the DC-2-and-a-half. The full tale can be found here.
This aircraft is so unique, and so outright wierd, that building a model of it is inevitable. That, however, is easier said than done. Finding a DC-3 kit to abuse is easy, in fact, I had some surplus. Spare DC-2 wings on the other hand are in short supply. Getting a wing is no problem, as MPM produce a DC-2 kit, but a wing isn't the same thing as a spare wing. The DC-2 kit costs roughly twice as much as the Italeri DC-3, and I hate throwing away most of a perfectly good kit after stealing a few parts from it (this would come back to bite me later on). The nice part of this relatively high cost of the DC-2 kit, is that it gives me an excuse to burn quite a lot of resources on alternative solutions. Time to fire up the spare parts factory.
A quick inventory created a shopping list for this project:
The most obvious part on the shopping list is of course the wing. I bought the MPM DC-2 kit, not
so much as a donor kit, but as a source for masters. I assembled the wing, then cut it off at the
very prominent wing fence just outboard of the engines. The DC-3 then got the same treatment. To
my enormous relief, the wings from the two models lined up every bit as nicely as the wings from
the two real aircraft. The MPM wing was up to the job. I closed off the end, added a pouring block,
built the biggest casing I've ever dealt with to create a mould, and dumped a pount of liquid rubber
over the suspended wing. I should point out that the wing in hollow, and thus very light, while the
rubber is quite heavy and liquid. Quick physics question: what happens when a light body is
submerged in a heavy liquid? Bingo, the sucker floats to the top. The idea of a mould is that the
part sits in the middle, not on top of a huge block of unused rubber with a very thin skin over it.
Enter a bad case of panic, followed by yours truly trying to sit still for over an hour while
holding down the wing with a pair of toothpicks while waiting for the rubber to cure.
The resulting mould obviously was only partly useable. The wing had floated decidedly off-center, making the mould initially useless. I cut away a load of useless rubber, rebuilt the casing, and dumped on another load of rubber to correct the issue. The final mould is useable, although the wings cast in it take a bit of cleaning up. Particularly nasty is the fact that about half of the top surface if peppered with small holes, probably as a result of the original moving about while the rubber was setting. It's fixable, but I wouldn't want to do series production with this mould.
Regardless of it's shortcomings, the mould for the wing alone has cost me as much as the Italeri kit in rubber. There's further moulds involved in other parts of this project, but by and large I think it will work out just a bit cheaper than simply buying a DC-2 just for parts:-)
The Flightpath engine set very helpfully provided a not-to-scale pattern for cutting down the
propellor blades of the base kit to match the early engines. Right, so they expect me to file
down six propellor blades to the exact same shape and dimensions based on nothing more than
an outline. Even I'm not that arrogant, this is a failure waiting to happen.
I do have a DC-2 sitting around of course, and not surprisingly, it has the required propellor blades. Unfortunately, these are not attached to their central axis (a horror scenario in and of itself, given that no jig is supplied to get them to line up), and the axis is of a different shape than that of the DC-3 with these blades. Once again, I had to get creative.
My first attempt a making a jig was a disaster. I used plasticine clay to create a negative of a DC-3 propellor, froze it in order for it to resist deforming while in use, chopped off the blades of a DC-3 propellor, and joined up the axis with three of the blades from the DC-2 kit. This worked nicely, except that the glue disolved the plasticine and made a horrible mess of the propellor blades along with it.
I then remembered that silicone rubber could also be used to make castings with disolved sprue, ergo, was impervious to plastic cement. I made a very fidgitty jig by pouring in effect half a mould for a complete DC-3 propellor. This allowed me to create a nice early propellor with the previously chopped axis and the other three blades from the DC-2, which then became the master used to make a mould for an early DC-3 propellor. Given the very fragile nature of this master, and the fact that I was already on my second and last chance to get this right, I did not dare use plasticine to hold the part while pouring the first half of the mould. Instead, I used molten vaseline poured into the rubber jig, on which I floated the master propellor. This combination was then frozen for extra sturdiness, and the first half of the mould poured on. It was a hot day over here, so I didn't need to heat the vaseline to make it let go of the prop easily, but that would have been an option. From there on, it was just a matter of conventional mould making.
Once I've got a sufficient number of castings from this mould, I'll have to repeat the trick to restore the DC-2 to a buildable state. This will involve removing the still intact blades from the DC-3 axis again, and fitting them to a DC-2 axis. The result will once again become a master for mould making. In a pinch I think I might be able to restore the wrecked set of blades, but I thing this will work better.
Italeri's idea of an interior for the DC-3/C-47 is rather insulting. They provide a floorplate with some rectangular blobs on it that are supposed to represent benches. This is ugly for a military C-47, and nowhere near useable for a civilian DC-3. The interior on the Esci kits, although certainly not up to any super-detailer's standards, at least looks like they had the right idea. For the civilian variants, they provide two passable rows of 6x2 airline seats. I chopped off a single pair from one of these rows, and made a mould for that. Since an early DC-3, as well as a DC-2, has single rows of seats, I then reduced that pair to a single seat, and again made a mould. These are now in use to supply a whole bunch of seats, for this project ( seven rows of 2+1 seating), a planned BT-67 conversion (seven or eight pairs), and the DC-2 (two rows of seven seats each).
That pretty much covered everything but the markings. The pictures I have for reference show Chinese lettering that is quite clear enough for anyone reading Chinese to know what's there, but I don't read Chinese. The prospect of copying these markings with Corel Draw from no more than the pictures is daunting. Then it occurred to me that I have several Chinese collegues, who would probably have no problem reading, and then typing these characters into a Chinese language document. This assumtion turned out to be correct, and I now have a document and a bunch of fonts that will allow me to print decals for this. Oddly, the Roman lettering turned out to be the bigger problem, as none of my hundreds of fonts matched the pictures. I ended up drawing the characters by hand..
At the time of writing this, the parts for this model are complete except for some seats, and the undercarriage
legs. I've made a start at building, beginning with the removal of the bench blobs from the floorplate,
and the installation of the civilian side door in the port fuselage side.
The picture to the right shows the current status of the parts production. The grey wing at the top left has seen some postprocessing, making the gazillion little holes easier to see. This particular wing has since been discarded, because to my unpleasant surprise the resin decided to deform after two days of curing (not very visible in the picture) The other grey wings are also copies, and so far show no interest in going funny on me. The grey-and-white propellor is the master I made from DC-3 and DC-2 parts, the grey one with the horrible amount of flash is the first casting. The beige cowlings are from the Flightpath set. The load of seats is the production so far, and will be stuck onto the now flattened cabin floor. I'm always a bit of two minds with these interiors; hardly anything will show on the finished product, but hopefully enough to make it worth my while.
It looks like the replacement undercarriage might turn into a long slog, so I decided to assume none would be forthcoming. I made a mould from the intact leg, and bought a length of 0.6mm spring steel. Pure resin would probably be too weak to bear the weight of the plane, especially with a solid resin starboard wing, and a bar of aluminium under the floor to keep the floorplate straigth; in fact, I had some doubts about plastic in this respect. Resin with a steel core should do nicely though. The first casting with core has been made, and although I don't think this one is good enough yet, the trick shows enough potential that I have faith I'll be able to make this work.
This project has taken a back seat to some group projects for a while, and in the meantime the new Airfix C-47 has come out. For some reason, this kit contains the old style propellers, and since they aren't needed for most builds I might use that kit for, all the hard work that went into the replacement props has been rendered irrelevant.
This project should start getting more attention again from here on, although intially the new Airfix Lilly Bell II will have priority, as I hope to finish that before the Dutch Nationals at the end of October.
Lilly Bell is finally nearing completion, and so this project is becoming more prominent on the workbench. Work has started on cleaning up all the chairs for the interior.
The replacement wing has been joined to the wing centre section. Since the resin wing is quite heavy, I didn't fancy trusting a simple butt join with the task of holding it in place, especially since the two different materials involved made a good sturdy bond challenging. I fitted a pair of metal hooks into holes in the resin section, and made a temporary bond with CA glue. I then made both this join and those between the top part on the original wing and the centre section watertight with filler, and poured PU resin into the cavity so created behind the wheel well. I suspect this is now the strongest bond that will be found anywhere in the model..
The join will take a bit of extra effort though, as the scale model wings are even more mismatched than the originals; the Italeri section in noticably thicker than the MPM part. I expect to spend quite some time fudging this to look good.
Not much activity since the last update; this project once again got eclipsed by others. Nothing seems likely to claim priority for some time now though, so I might actually start getting somewhere..
The picture to the right shows the status of the model earlier today. A whole load of chairs has been cast, finished, and joined with the floor. The colour differences are caused by different batches of resin. The interior has now been primed, and I should be able to start painting later this weekend. The wing has had some further light sanding, and I've mounted the replacement engines.
After playing around a bit with the steel cored resin undercarriage, I've decided to abandon that idea; the result wasn't all that sturdy, and I have some metal aftermarket parts available.
I was hoping to airbrush the interior today, but by the time I got around to working on this, the cat had settled down for a good long nap almost on top of the compressor. I don't think she'll ever forgive me if I fire it up now. Airbrushing postponed until Her Furryness decides to move..
I did get some work in on the engine mountings. The plastic bits were slightly larger in radius than the resin, so a spot of sanding along the edges was needed.
The seam between the resin and plastic will double as panel line, so I can't slosh filler over it and sand it smooth. I'll see what happens when I give it a generous dose of thick paint, and sand that smooth. I'm fairly optimistic this will seal the rim just nicely.
The thick paint worked; Humbrol gloss black filled enough of the gap, and closed any holes that were there (the rims weren't completely straight). Sanded off the paint around the trench today.
On the Airfix kits, the propellor shaft is on the engine, and the resin engines assume it's going to be on the propellor itself, so I had to drill the holes in both to a uniform size, and make the shafts from plastic rod. Nothing spectacular of course, but typical of the little bumps you get when mixing parts from all over the place.
While I was at it with the drill bits, I also opened up the ends of the engine exhausts, and dished the remaining DC-3 landing light. The inside of the landing light will be painted black, and drop high shine Alclad will go into the dish, which should give a very credible 'reflector' for the lamp. I expect to leave the wing alone for a while now, until I'm ready to join it to the fuselage.
The floor and walls of the interior have been airbrushed. That leaves the seats and backs of the chairs to be dealt with (the main bodies will be floor colour) before I can close the fuselage.
I closed up the fuselage today. Fit was mostly OK, but some squeezing was in order in some spots, along with a wedge to keep the rear wing join honest. Conveniently, a match turned out to be just the right size for the job.
I've put the fuselage through an initial cycle of filler-sandpaper-rescribing lost lines, and the result looked good enough to proceed to one of my favourite steps in airplane construction: sticking the main parts together and turning a bunch of parts into something that looks like an airplane.
The expected filler and sanding came and went, and I've primed the result. At first glance, it doesn't seem much more work will be needed, but I'll know more once the primer is completely dry.
Even if there are no new issues, I'll have to re-prime later. I know I'll have to restore some panel lines at the least, and right now, the windows are roughly taped over. I'll have to sand smooth the edge of the primer along the path of the tape, put in the windscreen, and mask things properly before further priming and the actual paint cycle.
The trick worked to the extent that the seam has been made nicely uniform. It is, however, bad enough to make the erstwhile Matchbox Trenchdigger weep for envy. This needed fixing..
Other than that the first shot of primer revealed only minor issues. Sanding, fitting of windscreen, proper masking, and next shot of primer scheduled for tomorrow.
I've airbrushed on the first few layers of gloss black, which will form the backdrop for the metallisers that will be the actual paintwork. It's not black enough yet, but I've seen enough of my gasmask for today, and the cat doesn't seem likely to forgive me if I wake her up again with the compressor. Later...
I'll be using some of the dull Alclads for this (probably semi-gloss aluminium for the 'new' wing, and dull aluminium for the rest of the plane, plus some yet-to-be-determined silver metallic for the control surfaces), and theoretically, those should be just as happy with grey primer. I'm not chancing it though; I've never met any metallic paint that didn't look good in thin mists over gloss black, while other undercoats haven't always been kind to me.
I've completed the black basecoat, and shot Alclad "semi-gloss aluminium" on the new wing. The rest of the plane will become "dull aluminium" later.
The older sides of the plane have been given a first several coat of Alclad Dull Aluminium. Right now, the appearance is rather splotchy (these paints take a lot of building up to an even coat), but the airbrush made it quite clear it needed cleaning, so the rest is deferred to tomorrow. That will also give me the opportunity to fix the leading edge of the tail, which now turns out not to be anywhere near as smooth as I thought...
It took a bit longer than expected, but I finally got round to completing the aliminium bits. Once thouroughly dried, I'll mask and paint the (fabric) control surfaces, probably with High Speed Silver, and then we'll see how good or goofy the three tastes of metallic gray paintjob really looks.
I've finished large scale painting, and the model is standing on it's own three feet. Not much longer before this one completes.
The decals are determined to make my life difficult. Given the somewhat rough surface of the dull Alclad, silvering was all but guaranteed to occur; not much you can do with that kind of surface. A generous helping of MicroSol should have been just the thing to limit it though. Some decals insisted on curling up around the edges, rather than lie down flat.
Attempts at correction only made matters worse. I ended up very carefully peeling/scraping some of them off again, and printing new ones (one advantages of home made decals, I guess). Still, after a few days of battling decals, I think I could get to like the result..
I'm guessing the black patches on the control surfaces are field repairs using tape. That would imply more patches on the underside of the plane, but I have no references for those, and so will do without. Exact amount of patches and damage is more or less an approximation; no two reference pictures show the same status.
Lesson of the day: concentrated alcohol is just the thing for removing Alclad...
Almost done. All that remains is dull varnish and glazing. I should be able to do that without further mishap..
She's finished, without further oopies. I'm not entirely satisfied with the combination of the decals and the dull metalliser, but it will do for now. If ever I find a way to do better, I can always build another.