By the end of my previous post, I’d completed all the necessary revisions to the kit parts to produce an in-flight model of Gidsken Jakobsen‘s ill-fated Junkers F13 floatplane, LN-ABH. (See the previous post for details of its fate.)
Unusually, I painted the fuselage and wing parts before complete assembly—because of the boxy nature of the aircraft, there were no seams that were going to need filling and sanding. One of the challenges was going to be to produce the smooth curve of black paint on either side of the fuselage at the nose of the aircraft, particularly given the very fine corrugations moulded into the kit parts. The kit provides a narrow, curved black decal, intended to act as a demarcation line for this paintwork, but the decal didn’t match the curve of the paint edge on the real aircraft.
First, I coated the kit parts with primer and then airbrushed on my Duralumin paint mix. In a fit of masochism born out of Covid lock-down and impatience, I didn’t use any of the commercial premixed preparations, but blended my own from Humbrol Aluminium and Gloss White, in a 4:1 ratio. (A lot of people complain that Humbrol is practically un-airbrushable, but actually it goes on quite nicely if it’s not thinned as much as usual, and is sprayed at a higher working pressure. I stirred in a little thinner until I got to a paint:thinner ratio of maybe 7:3, which is noticeably thicker than the usual “milk-like” endpoint for most airbrush paints, and then set my airbrush’s working pressure to 30 psi/2 bars.)
Then I scanned the (conveniently flat-sided) kit part and used that image as the basis to construct an appropriate curve using a graphics program, which I printed out at the correct scale, and glued to the back of a sheet of Bare-Metal Foil. I then used this as a guide to cut out the necessary curve in the foil using a new No.11 scalpel blade. Then I laid the foil on as a paint mask on the kit part, and massaged it into the fine corrugations with a cotton bud.
This rigmarole worked out well. (In the view below I’ve also filled the locating holes for the wire-frame step on the port side of the fuselage, which had been removed by the time this aircraft became LN-ABH, and replaced with a ladder. I have, however, not yet removed the little triangular tail-skid support, which was absent from the float-plane version.)
The elderly kit parts had all assumed interesting curves over the years, so it took a bit of effort to get the fuselage floor to fit into one fuselage half. I glued it a little at a time, gradually flexing the parts into alignment, rather than trying to get it done all at once.
The second fuselage half went on more easily.
I found I needed to leave the tail end slightly open, by a fraction of a millimetre, to avoid the roof part overhanging slightly in that region. The slight gap at the rear would be entirely covered by my replacement rudder. Here’s the fuselage largely assembled and painted, complete with new rudder, exhaust pipes and cowling tie-downs:
With Mika’s replacement decals still caught up in an endless Brexit/Covid postal delay somewhere between Finland and Scotland, and heartened by my success with the Bare-Metal Foil paint masks, I decided to make some stencils for the underwing registration letters. I scanned Mika’s original decals, corrected the “N”, and then printed the registration letters in reverse on the back of a sheet of Bare-Metal Foil.
Then I cut them out, and rubbed down the resulting stencils on to the underwing kit part (already primed and coated with Duralumin.
After a coat of black, the result fell into the not-great-but-not-too-bad category. The “B” in particular was going to need a little additional freehand repair work.
The float struts in this kit are notoriously difficult to attach, since there are multiple locating holes that all need to align simultaneously with multiple locating pins. So I decided to fit the floats to the unassembled lower wing section. This let me nudge each float strut into position in its correct hole, and then secure it with a little dab of cyanoacrylate gel from the inside of the wing, before moving on to the next one.
Once the floats were attached, I also added the boarding ladder connecting the float to the wing-root on the port side, putting it together from short pieces of 0.5mm brass rod. There seem to have been two versions of this ladder, one near-vertical and one sloping:
Without any evidence to suggest which was the later version, I went for the more vertical option.
With the fuselage largely completed, I was able to dry-assemble the bulk of the aircraft to check its centre of gravity, because (as an in-flight model) I wanted to put this one on a stand. There was plenty of room inside the thick chord of the wing to place a small neodymium magnet, which I could use to attach the model to a similar magnet on an old transparent Airfix stand.
Then I closed up the wing.
The areas where I’d removed the moulded kit ailerons had a tendency to gap too widely, so I slipped in a little styrene strip as a spacer, and to provide an anchor point for the Master-X resin replacements.
These went on nicely, with only a tiny amount of sanding to get a neat fit along the length of the parts.
At this point, I gave wings and fuselage a coat of gloss enamel varnish and set them aside, still separate, to await the application of decals.
Next time—a much more straightforward build for D 260.