Aircraft designers have often deviated from the conventional in an effort to gain advantages or better suit an aircraft for a particular role. During World War II, one approach taken by a number of engineering teams was to resort to twin booms for a single- or twin-engined aircraft, as, for example, the Lockheed P-38, in order to concentrate forward-firing armament, or with the Fw 189, to maximize visibility for a tactical reconaissance airplane. Designers of medium bombers or transports also sometimes went to a trimotor configuration instead of the more typical twin engines, for the sake of redundancy or to compensate for relatively less powerful engines; the Savoia Marchetti family of aircraft and the Ju 52/3m come to mind. However, there is only one airplane from this period that had both twin booms and three engines, the Blohm und Voss BV 138. Despite, or perhaps because of, this unusual combination, it was effective in its role as a maritime reconaissance flying boat for the Luftwaffe. Not surprisingly, it looked like nothing else; its nickname, 'the flying clog,' was pretty descriptive. One may fairly describe it as ugly, but in an intriguing sort of way.
When I'm inclined to build a big model, it will probably be a flying boat. Three years ago, I built the Mach 2 Do 26; this January, I got the bug for a big model again, a consequence of picking up a copy of Supermodel's 1/72 kit of the BV 138 via E-Bay. This molding, about thirty years old, is the only kit of the BV 138 in 1/72, and given the subject matter, probably will remain so. The good news is that the kit is injection molded, to a much higher standard than Mach 2's Do 26, and the major components are correct in outline. The bad news...well, read on.
As always, research was the first step. Fortunately, there is a decent amount of information on the BV 138. William Green's Warplanes of the Second World War (Volume 5, Flying Boats) (1961), his Warplanes of the Third Reich (1970), and his article with Gordon Swanborough in Air International Vol.17, No.5 (November 1979) have valuable exterior photos and drawings, including a cutaway drawing in the last-mentioned reference. One could rely on these alone if the interior appointments of the kit were more accurate. As the kit interior is both sparse in detail and mostly wrong, I purchased a Polish profile, Wydawictnwo Militaria #64, Blohm und Voss Bv 138 , by Janusz Ledwoch (1998). This gives a half dozen or so interior photos, though of marginal value with regard to the flight deck, two more cutaways, separate double-sided 1/72 scale plans of roughly 17" x 22" dimensions, and various other visual material. Unfortunately, it is written in Polish, with some terse English captions here and there, but we always buy this stuff just for the pictures, right? Apart from the sources I used, there is also a Schiffer book and perhaps another monograph, neither of which I have seen.
Despite the injection molding, this kit has a lot of conspicuous seams which, combined with raised surface detail, promised to require a lot of work to resolve. I began with the twelve-piece beaching trolley included in the kit; this was a harbinger of what was to come, for the tubular components were not well-engineered, requiring substantial amounts of CA to round out the joints. Furthermore, photos showed beaching trolleys completely unlike the one in the kit, so I wonder if it's authentic. Still, once assembled, it looked good, fit the hull, and all four wheels met the ground.
On to the main event; I started with the booms, and immediately saw that I was going to go through a lot of CA. Both booms had a pair of sink marks on the upper front surface of the engine nacelles, and the lengthwise seams also needed work. The radiator intake was a separate 'U'-shape piece of very thin cross-section; both had broken in transit. Fortunately, I was able to piece them and a propeller back together again, but the intakes didn't fit into the nacelles particularly well. I didn't address those seams right away, though, because I wanted to take a close look at photos and drawings first.
Next I put the wings together, top and bottom each side. Again, the seams weren't wonderful, but not as bad as the booms. However, once these dried, dry-fitting the booms to the wings revealed gross alignment problems; the boom assemblies sat so high that the bottom of the nacelles did not match with the wing portion to the tune of about eight scale inches. More on that later.
Four large subassemblies and the beaching trolley to the good now, I was thinking how much better this kit was than the Do 26. Then I took a good look at the components supplied for the interior of the boat. What a horror.
Now, I am not that fond of doing interior detail. If the kit components are even halfway decent, I'm happy. A close look at this kit made me very unhappy. It wasn't just that the cockpit was rudimentary. The kit also comes with two turrets and an open dorsal gun position, and none of the internal bulkheads were included. In fact, from the dorsal position of this kit, it is possible to look forward to the front of the center engine and down to the bottom of the hull. Likewise, each of the turrets are open enough to allow various and sundry views of the extreme nose compartment, the extreme stern, the back side of the instrument panel, and forward into the lower aft hull. The capper is that there is no separation between the flight deck and the navigation/radio compartment; it is inaccurately represented as one gigantic cabin, and what is shown aft of the flight deck in no way resembles the real thing. It was evident that at a minimum I was going to have to fashion several bulkheads to house off interior areas that should not be visible and cut apart some of the parts supplied with the kit. I also discovered on dry-fit that the cockpit glass didn't.
The very first thing I did after these discoveries was to ask myself if I really wanted a 11" by 16" model of a profoundly ugly German flying boat taking up space in my study. Inexplicably, I still did. So, the next step was to purchase a contour gauge so I could fabricate interior bulkheads with some speed and accuracy. Next, I went on the net searching for aftermarket sets. There isn't much for the BV 138. Fortunately, one of the Falcon vac canopy sets includes the glazing for this beast, but apart from that, all I could find was Aries MG 151s for the turrets and an Aeroclub MG131 for the dorsal position. The guns were a convenience; the glazing absolutely essential. I ordered the stuff, then went back to the bench.
Before beginning my toils over the interior, I had to add a couple of two-inch 'L'-section pieces to fill in the contours of each hull side. I have no idea why the kit was designed this way, but it was impossible to align the pieces to match either the hull surface or the fuselage sides. Okay, I figured I'd just CA and putty them into submission. Unfortunately, the seams would spring just as I had achieved a level of finish I'd desired, requiring more CA, more putty and more sanding. I lost count how often this happened, but I did eventually get it all cleaned up.
I took interior contours of the hull with the contour gauge, and traced the pattern onto .020 plastic card. Cut out, the bulkheads started slightly too big, so it took a little rasping, shaving, sanding and dry-fitting to get them right. I ended up fabricating bulkheads for the following positions: between the nose turret and the flight deck; between the flight deck and the radio/nav compartment; between the crew rest area and the aft turret (two pieces); aft of the rear gunner; both the front and back of the dorsal gunner's position; and, deep within the central nacelle, but still visible, the aft part of the engine firewall. Three of the bulkheads had watertight doors in them, but the only one I had to cut out was in the bulkhead aft of the flight deck, as for the others the door was hinged on the visible side. The flightdeck-to-navigator's-station door was the toughest, requiring a precise cut-out, and then detailing with Plastruct rod of two different small cross-sections. For the others, I generated adequate detail with various types and diameters of rod over oval-shaped doors.
The most bulkhead detailing required was for the the central nacelle firewall backside, which was visible through the opening behind the dorsal gunner. A ladder, various pipes, a hydraulic header tank, frames, stringers, and other fixtures were visible in this passage. The hydraulic lines were made from .005 rod, the header tank was fashioned from a left-over 1/48 resin exhaust stub from the Classic Airframes Westland Whirlwind, the frames were fabricated from 'T' cross-section Plastruct rod, the stringers were from .20 x .40 rod, and the insides of the crew access doors were modified photo-etch dive brakes from an Airwaves set for the Meteor NF 14. The ladder inside the nacelle descending into the flight engineer's station was cut down from an Airfix Catalina, two other fixtures were created out of an aft funnel half of the Airfix 1/600 Cossack, and a number of other anonymous resin and photo-etch bits were stuck on as well.
I used some more plastic card to fabricate the floor of the dorsal gunner's position and the step behind it into the central nacelle. Some areas here and there also had to be built up with CA and microballoons, especially where the bulkheads I fabricated had slight gaps.
I detailed the cockpit by adding PE side panels originally intended for the back cockpit of the Meteor NF14, as well as generic PE rudder pedals, and bits sawn off a 1/48 P-51D radio. It was also necessary to saw off about 11/4 inches from the aft end of the flight deck floor, so that the bulkhead would fit. Part of this sawed-off piece was used to provide a floor under the forward turret, thus hiding the inside of the hull chine. More 'T' rod was used forward to simulate hull stringers, just in case some of this area was visible through the forward turret. I also fabricated a first-aid locker on the right wall of the cockpit, postulating that there would be one there because of the external red cross marking just behind the cockpit glazing on that side.
After working about eighty parts into the interior detailing effort, I started to have a glimmer of hope. Some Dremel work was necessary to get the two fuselage halves to dry-fit together properly, involving sanding edges of bulkheads and the aft end of the flight deck floor. This was only an intermediate fit, though, as I still had interior work to do under and near the bow and stern turrets. I built the crawl-way floor to the extreme nose out of one of the plethora of plastic card scraps that by now littered the bench, and attached it. I did much the same for the area under and aft of the rear turret. By now, I was at the point where I would need the transparency set to get any further in the turret areas. Thus I turned my attention to the flight deck.
First I attached the rudder pedals--at least the kit provided supports for these. The main instrument panel was featureless, a decal being provided to add detail, but the mounting point for the panel is too far aft, leaving a gap along the cockpit front edge. Consequently, I clipped the mounting pin, filled the receiving hole, and mounted the panel as far forward as it would go.
The pilot's and observer's chairs were actually usable, as they approximated the right shape (after the mold marks were sanded off the seats). However, they had neither the headrests nor the steel tube shock frames on the back and below. Fortunately, I had lots of styrene rod--six lengths of .010, plus the use of a couple of Frog Me 410 aileron mass balances for the headrest supports, and short bits of CA-filled .060 tube for the headrests themselves, vastly improved the appearance of the chairs.
I had a lot of trouble with the control wheels. Compared with the rather clunky control columns, the wheels were very delicate--so much so that both broke when I removed them from the sprue, despite the use of a sprue cutter. Luckily, they went back together well after I got rid of the attached sprue and fiddled with the shards under magnification for about ten minutes.
I alternated attention to interior details with effort devoted to the wings and booms. Mating each wing to its boom demanded anything but subtlety, as some heavy rasp work was required on the upper mating surface of each wing to get the matching boom assembly to snug down and align properly. And of course, the rift thus created in each case was heroic in its proportions. Aw heck, it's just CA, and a lot of sanding. The sanding put paid to all the raised detail within a kilometer or so of the seam, as well as the exhaust ports for the engine; exhausts fabricated out of styrene tube looked better anyway. I used tube to replace the fuel dump vents underwing for the same reason.
The wing-fuselage joins presented two problems. First, the mounting pins on one side were slightly misaligned, resulting in that wing being about 1mm higher than the corresponding wing root. This was resolved by filing down the already small-diameter mounting pins even further. This exacerbated the second problem: just two small pins on each side were all that distinguished the junction from a butt joint. I felt the strength would be inadequate for so large an aircraft. Consequently, I decided to add some spar support. In order to discourage droop, I drilled a 9/64" hole at a 30¡ upwards angle from the inside of each fuselage half, through the root plate of each wing assembly (between the original mounting pins), and inserted lengths of .15 styrene tube long enough to wedge against the inside of the top wing; the end of each tube was cut at a 60¡ angle for maximum surface contact. To aid alignment, I first painted a blue stripe on the top side of each tube; otherwise, I would have had trouble being sure the angle cut was hitting the inside of the wing correctly.
The propeller assembles require precise work if you desire to have units which will rotate. As I didn't care, I paid primary attention to getting the painting right and the five piece assemblies in alignment. They would not go onto the model until after painting and decals.
The starboard wing went on first; the root seam wasn't too bad, as at least the wing and the root matched well. I then varied from usual practice by attaching the various small bits to the wing. Originally, I thought to paint each half of the model separately, minimizing the amount of masking around the interior gaps, and easing interior repair if something went wrong. Later in the build, I discovered this was unnecessary, since the turrets did not need to be mounted until after sanding and painting.
The port wing was a little worse, as I had had to whittle down the mounting pins to minimize misalignment, but I was able to confine the misfit to the underside of the root. I did not do the small bits on this yet, as I had by now changed my approach.
The aftermarket parts had arrived. The transparencies were far superior to the kit items they replaced, though I still had to use the porthole windows and two sliding panels in the cockpit area. The Aeroclub MG 131 (two came in the package) were lovely white metal castings. On the other hand, the Aires MG 151 (four) consisted of nice resin breech assemblies, and separate barrels that weren't so nice: one was straight, two were severely warped, and the fourth moderately warped. I eventually got the second straightened out with hot water and lots of rolling on the table top. Of course, none of these various bits were designed to work with each other.
The first step for the guns was to take the MG 131 gun mount from the kit and cut the gun away, leaving just the mount. This was a tense bit of surgery, as the arms of the mount weren't very hefty, but I managed by dint of magnifier, X-acto and Dremel to trim it down. I gently hand-drilled with small drill bits, starting with a #80, and eventually working up to a #68, which gave me a hole in the center of the mount in which to lodge the Aeroclub MG 131.
The Falcon windscreen/canopy was easy to cut out and paint. The Falcon turrets were a little trickier, and, though lovely, provide the complication that there are no provisions for mounting the MG 151 inside; this is interesting because the kit transparencies have a projecting bar from one side to mount the kit guns. It looks awful, of course, which is why I decided to go with the vac turrets, but I was now faced with fabricating something convincing to put inside each turret.
As it happened, years ago I parted out an Airfix B-24; I still had the nose and tail turret hulls in my spares box. With a little surgery, some styrene rod and sheet, lengths of 1/48 .50 caliber ammo belt, and some detail painting, I came up with internals that would mount the MG 151 and slide up inside each transparency. The breech assembly front end snugged up against the turret slot; I drilled this out at the appropriate location and attached the barrel, although first both turret transparencies were glued to the respective turret hulls with Aleene's Jewel-It.
I painted all the interior areas with a coat of Polly Scale RLM 02, then added detail in other colors, mostly NATO tri-black. I also used a wash based on RLM 74 to bring out detail, especially around bulkhead doors. I added a Red Cross decal on the first-aid kit in the cockpit, and the decal for the main instrument panel.
It was now time to mate the two halves of the hull, with wings already attached. Because the alignment was equivocal, and required some force to achieve, I used CA as the bonding agent. Except for the area between the cockpit and the center engine, things went together pretty well. There was only about two inches of seam on the planing bottom, though this kit has a reputation for trouble there. The one hard-to-resolve seam, behind the cockpit, is so because the top of the fuslage decking goes underneath the central engine radiator housing, thus giving a 'U'-shaped seam with a very narrow access area. The same seam goes through the central engine nacelle and radiator as well. Resolving the seams took a while, though except for the area aft of the cockpit the seam reduction was unremarkable. I had some trouble finding a tool narrow enough to sand down the CA I used at the deepest part of the aforementioned 'U'; I eventually resorted to using a Zona saw. That worked reasonably well, as I managed not to saw the central engine off the rest of the model. As for the radiator seam, I had anticipated this problem, and had previously cut a piece of sheet styrene to fit the face of the radiator--you don't have to fill what you can hide.
I now realized that there was an alignment problem. The stabilzer, when dry fitted, was marginally higher on one side. After looking the whole model over for the source of the error, I concluded that the left boom might be 2mm higher than the right. Short of sawing through and remounting a boom, the only solution I saw was to sand down the stabilizer mounting pins so that it could mount a little up on one side and a little down on the other. I did this; it made the misalignment much less obvious.
I was pleased to find that the turrets as assembled now would pop right into the holes, and the Falcon cockpit transparency fit well too. I added most of the remaining small detail pieces to the wings, and the skeg on the underside of the aft hull. It was now time to begin painting.
The beaching trolley received a coat of RLM 70 black green, with RLM 66 black-gray wheel hubs and NATO tri-color black for the tires. This looked better than what I imagined it would look like if painted black per the kit instructions.
The basic scheme I chose for the aircraft itself was a 72/73/65 splinter, a typical German over-ocean scheme, but the particular aircraft I was doing also had yellow wingtips on the underside and yellow bands on the booms. So, the first order of business was to airbrush the yellow on. Next I airbrushed the wing floats with RLM 72. I then masked over the portion of the yellow for the wingtips and bands and RLM 72 for the floats that I wished to retain, and airbrushed the underside coat of RLM 65. The first coat revealed a plethora of small flaws, which I expunged before repainting.
With the underside coat applied, I masked further and airbrushed RLM 73 on the sides and top. Again, some flaws were revealed, and dealt with. Still further masking established the splinter pattern I wanted, and I applied the RLM 72. The difference between the two topside colors was so small that I wasn't sure I'd even used the right color until I peeled back the masking. Finally, I removed all of the masking; a few places required touch-up, but the most grueling part of the painting was done.
The control column and seat assemblies went into the cockpit next, followed by three 50 Kg bombs underwing. The kit bombs were so misshapen that I raided the spares box for some better-looking ones. This required that the existing bomb-mounting holes be filled, sanded out and painted over. The new bombs with integral pylons were then attached with CA and the paint touched up. I also did detail painting of the cleats, exhaust pipes, fuel dump pipes and intake interiors now.
After airbrushing on a gloss coat with Future, I was ready to add the decals. The kit decals did not cover the specific aircraft I was modeling, 7R+RL of 3./SAGr 125, and the carrier for the kit decals had discolored, so I needed some supplementary decals. Only the external red cross marker and the two unit badges came from the kit sheet. Various leftover kit decal sheets and aftermarket 10mm Luftwaffe code sheets provided me with everything else. Once again, this hobby has demonstrated the value of being a packrat! I also used some black strip decals to simulate the cowling face intakes.
With the decals on, I shot another coat of Future, followed by a coat of Railroad Flat after two days of curing. Then the last bits went on: seat belts in the cockpit, dorsal MG 131, the two turrets, the cockpit glazing, pitot, D/F loop, antenna mast and the three propeller assemblies. The wingtip landing lights were painted next, then highlighted with Future. I also cleaned up the port hole windows, which were masked over at the start of the painting, and highlighted them with Future as well.
I'm not necessarily done at this point. I'll probably add antenna wires, and I'm considering some pastel work to highlight exhaust patterns, but for the purposes of this article, the model is done.
Though I bemoaned the truly horrible interior, getting there on my own has certainly been fun, and I managed to overcome most of the fit problems. In short, I'm happy with the result. And I think I've got the large-aircraft bug out of my system for a while. On the other hand, the closet still contains a PBY, a Do 24, a Stranraer, a PB2Y and a PBM...
