Aeroclub Sea Otter Mk.II

Aeroclub's Sea Otter is a mixed-media kit with vacuum-formed fuselage (hull) halves and canopy; injection-molded wings, empennage, nacelle, wing floats and interior details; and white metal engine, propeller, landing gear, wheels, nacelle and wing float struts and small interior details. The quality of the parts varies. The vacuformed parts look quite good, with light detail on the hull sides. The canopy framing is fairly indistinct, however. The injection parts are well done, with minimal molding flaws. They are molded on very heavy, brittle sprues, and the attachment points and mating surfaces will require a lot of clean up. The interior parts show good detail, considering the limited run molding. The white metal parts are a bit disappointing, given that these are Aeroclub's speciality. Heavy flash is present on many of the parts, and pitting is evident in some prominent areas. Also included are lengths of strut stock, rod and strip for fabricating external details and most of the struts.

Decals are included for a Malta-based FAA machine. Model Art provides suitable markings, with a choice of 2 Indochina-based Sea Otters of Escadrille de Servitude 8S and 9S on sheet 72/031. This sheet also provides an excellent discussion of the relevant colours for the a/c, with the final decision being left up to the modeller.

Instructions are a bit weak, with a three view showing the FAA colour scheme, and a single written sheet describing the assembly process in general terms. The weakness of the instructions is particularly evident in the cockpit, where a general diagram of the parts would be very useful. Careful study of the parts should help sort out what goes where. As far as I can figure, the interior goes together something like the following:

There are three bulkheads mounted on the floor. The frontmost includes the instrument panel and the rudder pedals. This goes at the front of the floor, mounted ahead of the frontmost raised rib. The next bulkhead features an open doorway. This should be mounted in the recessed slot on the floor, with the hatchway to starboard. The hatched area on the forward side of the bulkhead is the mounting for the pilot's seat. The raised rib on the back indicates the location of the navigator's chart table, which is what I eventually decided the mysterious rectangular part was. This should be mounted with the small notch facing outwards, to clear a raised rib on the sidewall. The final bulkhead has a hatched area for the navigator's seat and a curtained hatchway. This should be mounted on to the rear of the floor. The sidewalls can be added to this. The port sidewall features a crude compass and throttle quadrant molded into it. When the white metal seats (with suitable belts from tape) and the control column are added, the result should be a fairly detailed cockpit, considering the nature of the kit.

Clean-up of the kit parts began with removing the mold parting lines from the white metal components, many of which required further filling and sanding to remove pits and other flaws. The injection molded parts have a fairly uneven texture that becomes evident with light sanding. A quick rub down with 1200 grit sorted this out, however. All the tabs and slots molded into the injection parts need a lot of refinement with files to be useful. The wonderfully clear canopy suffers from very faintly molded framework, and the bottom edge of the canopy is poorly defined.

I began assembly with the upper wing/nacelle assembly. After cleaning up the mating surfaces of the nacelle vacuform style (wet and dry taped down), I cleaned-up and enlarged the mounting slots for the upper wings. Lots of trial fitting was required here. When assembled, there was a 1 mm gap at the rear of the horizontally split nacelle, which I filled with scrap plastic. The trailing edges of the wing roots are nearly twice the thickness of the corresponding wing trailing edges, and they lack the appropriate dihedral, so I filed them heavily into shape. I added the rear of the cowling after cleaning up the mold lines and mating surfaces. The rocker valve cover detail on the cowling is a bit soft, so be careful when filling an sanding. I CA-ed the cowl to the nacelle, and then filed the white metal leading edges of the wing roots to match the plastic of the nacelle. To this the wings were added, with some filing of the mounting tabs to give the appropriate dihedral indicated by the assembly drawing. Copious amounts of filler were applied to the seams, and the whole thing was left to set. When hardened, I cleaned-up the wing roots with files and wet and dry paper. I added the carburetor intake and the small intake to the rear of the nacelle. Both scoops were mounted and faired in with CA. I gave the whole assembly a coat of Halford's grey to check for remaining seams, then refilled and sanded. It was evident that the wing assembly was going to be very heavy (and I hadn't added the engine, exhaust collector ring or the prop yet), so I began to wonder about the strength the the strut stock used to support the upper wing. At least there are a pair of white metal struts to bear most of the weight.

I added a lot of stiffeners to the fuselage halves, particularly directly below the engine and at the wing mounting points. The fuselage is at its widest at this point, and you need a pretty rigid structure to mount everything to. I added some scrap plastic strip below the wing mounting slots to provide a more solid attachment point. After test-fitting the lower wings, I added some stretched sprue to act as a shim and improve the security of the mounting. I decided not to open the horizontal stab mounting slot until the fuselage halves were glued together, to ensure the slot was level. I built the cockpit interior as three subassemblies; the floor and the front and rear bulkheads; the middle bulkhead, port sidewall and the navigator's table; and the starboard sidewall. These were painted separately before assembling the whole. This method made painting the details a bit more difficult, but it allowed a more rigid structure during final assembly of the cockpit components.

With a bit of fiddling and a lot of filing of the cockpit components I managed to get them together and into the fuselage halves. The fuselage went together well, though care must be taken to ensure a nice sharp and straight chine on the underside. Once this was set, I cut out the slot for the horizontal stabiliser and fitted the stabiliser, ensuring that it was mounted far enough forward, and that the opening between the elevators was sufficiently broad for the rudder to fit well. This also required some clean up of the mounting edge of both the fuselage and the rudder. I drilled some small holes in both components to insert fine wires and ensure the rudder remains securely mounted. I cut two notches in the trailing edge of the rudder, and inserted short sections of sprue to simulate ID lights. The wings were secured into the braced slots, and any gaps filled with superglue and sprue and sanded smooth. A notch was cut into the leading edge of the port wing to install the landing light. A hole at the back of the aperture simulated the lamp, while the cover was made from clear sprue, sanded to shape and polished in place.

The next step, and the first part I was dreading (attaching the upper wing was yet to come), was attaching the transparency. The kit part is wonderfully clear, and reasonably thick, so that it has some strength. The framing is very faint, so this will present a problem when masking. A large section at the rear of the canopy is actually a part of the fuselage. this will give you sopme space to work with when fairing the transparency into the fuselage. After carefully trimming from the backing sheet, I established what I though were the edges of the part with thin strips of tape. I then trimmed and sanded the part back to the edge of the tape. Establishing the bottom edge of the windscreen was particularly tough- all I can recommend is lots of trial fitting. Once I was happy with the fit, I dipped the canopy in Klear (Future), and added a 1.5 mm wide scrap plastic shelf at the top of the rear cockpit bulkhead to provide a solid mount for the canopy. The canopy was then superglued in place and left to set for several days. When I came back to the kit, I found to my horror that the rear edge of the canopy ended up about 0.5 mm wider than the fuselage. I didn't really have room to try to widen the fuselage, so I was left with the option of narrowing the transparency at the rear. Conveniently the rear 10 mm or so of the top surface of the transparency is actually a portion of the fuselage, so this can be sanded, cut, etc. without fear of marring the finish. I drilled a small hole in the top of the part, just behind the sloped portion, on the side where the mismatch occurred. I then cut a slot from this hole back to the edge of the canopy. I could then squeeze the part to the correct width at the rear. The drilled hole stopped the slot from cracking the entire canopy. With the canopy held in the correct position, I superglued the slot shut. I was then free to liberally putty the transparency into the fuselage. While I did this I masked off all the portions of the transparency that were to remain clear, including the framing. I planned to add the framing from painted decal film at a later stage.

I next drilled holes for attaching the rigging. I attached the outrigger floats to the lower wing without much fuss, though I did enlarge the mounting holes, and clean up the pins on the struts. While I had planned to install the upper wing prior to painting, I came to the conclusion that this would make painting a nightmare. My eventual strategy was to attach the engine bearer struts to the underside of the nacelle at the appropriate angles, then paint the upper wing and fuselage, combine the two painted assemblies, and finally add the interplane struts and rigging.

At this stage I began painting. After a primer coat of grey, and preshading of the panel lines and shadow areas in black, the undersides of the hull, floats, landing gear and wheel hubs, and both wings were painted Humbrol sky. These areas were then masked with Tamiya tape, and the upper surfaces, along with the underside of the nacelle, and all struts, were painted Humbrol dark sea grey. This was then lightened in selected areas with a coat of dark sea grey mixed with a drop of white. This helped create some visual interest on the drab grey surface. The masking was removed, and the model was glossed with Humbrol gloss clear and left to stand.

Once the clear coat had set, the hinge lines of the control surfaces and flaps were brought out with a watercolour wash of black (on grey areas) and brown-black (on sky areas). The wash was also applied to the wheel recesses in the lower wing and the gear itself. Excess was polished off or removed with a dampened cloth. The wash was sealed with a further coat of clear, and then it was on to the decals.

The markings for Escadrille de Servitude 8S came from Model Art Decals' sheet 72/031. The decals are very well printed, and quite thin. Accurate registration and opacity is ensured on items such as the roundels by building up the final image from multiple layers, ensuring each is given adequate time to set. The only fault I found with the decals is there tendency to stick wherever they first contact plastic- and resist almost all efforts to move them. That being said, most of the markings are quite tough, and can sustain a fair bit of handling. The footprints indicating the wing walkways are supplied as individual decals. This cuts down on carrier film, but it make alignment tricky. There are thin black outlines for inboard walkway area on the lower wing. These became hopelessly tangled when I tried to apply them, and in the end I discarded them. They could be easily replaced with any thin black striping.

With the decals in place, a coat of clear flat was applied, and once set, the hard part began. With lots of adjustment, the upper wing was attached via the engine struts. While I was happy with the wings being parallel, I think I may have introduced a hint of negative stagger. It's hard to be sure, because of the pronounced tail-down attitude of the aircraft on its wheels. The prepainted interplane struts were installed next, after trimming to the appropriate length. All struts were secured with small amounts of superglue. Gaps were filled with Tipp-Ex (White-out). The landing gear was added, along with the rudder. The rudder was deflected slightly, and the tailwheel posed at the same angle. I filed flats onto the bottoms of the white metal wheels. The wheels are canted outwards, so bear this in mind when flattening the tyres. I ended up having to correct a slight tilt to the whole aircraft by sanding one wheel move heavily, and adding a small shim to the other.

I next began the rigging. All rigging was done with monofilament (invisible sewing thread). I had drilled blind (part-through) holes for all the wires, so each line was cut oversize, secured at one end with a touch of superglue, and once set the free end was trimmed slightly overlong and glued into the corresponding hole. The slack was taken out of the rigging by passing a smoking wooden splint near each line. This can be a tricky business- if you get too close, it's easy to snap or melt through the monofilament. The thread also has a tendency to relax and sag after beign stretched, so it make take several passes to get a satisfactory result.

After completing 90% of the rigging, I was still having trouble with a few wires that just did not want to stay in place. At this stage I decided brute force was in order, and I drilled right through the wing in the appropriate locations. I could then pull the thread through and hold it taut while the glue set. The holes in the wing were filled with small sections of stretch sprue, and sanded flush. In hindsight, this was a far superior approach, and IF I ever build another rigged model, this is the way I'll go about it.

The rigging was painted silver and all the attachment points and glue marks were touched up in the appropriate shades. At this stage I started adding some of the details shown in the plans, but not provided in the kit. This included flap hinges on the underside of the upperwing, a pitot tube on the port forward interplane strut, a whip and wire aerial, and yagi radar aerials. These details were scratchbuilt from sprue and more monofilament. Note that the wire aerial should run to the tip of the rudder, in line with the hinge. I made the yagi aerials by cutting notches in some thin sprue, then laying thinner sprue dipoles in the notches. The assemblies were secured with superglue, and painted black once complete. All the touch up and new parts were blended in with an overspray of clear flat.

As a final touch, I added the canopy framing from painted decal film. I sprayed clear film with interior green and then grey or silver, and cut this into thin strips which were then cut to length to fit the model. I couldn't seal them with a clear coat, so I used thinned Krystal Klear to stick down any loose ends.

As is often the case, I obtained excellent reference material after the model is finished! In this case I was given a copy of AFM (Aviation Francaise Magazine) No 4, which has many photos of Sea Otters in service with Escadrille 8.S.

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Last updated 17 May 2001