Building an 'Improved' Wallace RC 1/16 scale KAIRYU Suicide
A Report to the Cabal:
Yesterday I invested a great deal of time to tighten up the fit between the upper (access hatch) and lower hull halves. This basically is a process of screeding in catalyzed filler at the seam formed where the two hull pieces fit together, contouring the filler a bit with either a screeding blade or a putty-knife, then quickly running a knife blade along the seam to prevent the filler from permanently bonding the two halves of the hull together. Then contouring the built up filler with files and sandpaper.
I also worked up the fit between the big sail and the top of the hull -- there was a bit of a list of the sail as delivered and I had to shave off some material from one side of the sail to get it to fit straight on the hull. I also worked out a means of securing the sail to the hull with fasteners that would permit me to quickly remove the sail in the field.
And finally I did a quick test fit of the sail and exhaust pipe to check fit of the detail pieces. Here goes:
There was a substantial gap between the upper hull and lower hull where there joined in a radial beak at the stern. I coated the inside surfaces of the upper hull with wax, gopped on some filler to the radial flange of the lower hull, then slammed the two pieces together. Waiting a bit for the filler to cure hard, I pulled them apart and, bingo, I had a nice tight fit between the two at the after radial break.
Further work involved re-contouring the stern with filler as I found that the hull was a bit out-of-round in a few places. Once a mass of filler had cured hard I first attacked it with a bastard file, then a first-cut file, then sanding blocks equipped with #100, then #240, and finally #400. I followed with a heavy shot of 131S primer.
It's amazing how well the Evercoat fillers stick to different substrates -- you can take this stuff down to a fine feather-edge with no evidence of failure. You're looking at the work ready for primer.
Throughout the contouring work on my KAIRYU I used the Evercoat Metal Glaze, a very thin polyester based filler, often referred to as 'icing'. Above demonstrates how I use it at the longitudinal seam between the upper and lower hull to get them into alignment: The stuff is laid on with putty knife, screed blade, or stiff brush. Before it cures hard I run a knife along the seam to keep the filler from bonding the two hull halves together.
Using a disposable brush to apply the just mixed Metal Glaze filler. The knife is sitting on the pallet I use to mix the filler with its cream hardener.
Using a sanding block to smooth out the primed sail
Once all the filler work had been done on the hull and sail, I touched up the filled areas with primer, then blasted the model parts with a heavy, wet, coating of primer.
I made a simple alignment tool from scrap plastic sheet. Setting this gauge on the upper hull, I used it to site the top of the sail, shaving one side of the base of the sail till it sat straight on the hull. I used carbon-paper to identify the low spots on the sail that needed to be shaved with sanding block. You do it like this: Carbon-paper is put down on the hull, carbon side up. The sail is slide on the paper, fore and aft, the sail lifted off and examined -- wherever the black appears on the base of the sail, I attack that area with sandpaper. This work continued until the sail sat straight on the hull.
After installing mounting brackets within the sail, I drilled mating holes in the top of the hull through which 6-32 machine screws would pass, making up to the base of the brackets within the sail. Note that I've marked the big hole that will be cut into the hull -- this will permit examination of the sail mounted wireless video camera WTC without need of removing the sail.
The various brackets used within the sail. The forward 'U' shaped foundation bolts to the bridge well and receives the video camera WTC. Another 'U' shaped strap (not shown) goes around the other half of the WTC, holding it in place. The two brackets back aft mount within the sail and have a hole to receive a fastener that runs up from inside the hull to secure the sail in place.
Testing fitting the WTC equipped sail atop the upper hull. We're looking up through the bottom of the hull. The big hole permits easy examination, even removla/installation, of the WTC without needing to remove the sail. Neat.
Test fitting the sail and exhaust parts for proper fit.
Today I work on getting the control surface linkages to work properly and to affix the three sets of stabilizers.