(Reproduced from Small Scale Aviator magazine: Vol 1 Number 3 - Winter 1997 - Author: Bryan Ribbans)
Ask anyone to name some WW2 flying boats and you should get three or four answers. Ask them to do the same for WW1 'boats and the more knowledgeable might mention the Felixstowe, or maybe the Curtiss types. But ask them to name the first successful all British design and you will be met with silence! Asking for names of Sopwith designs and types such as the Pup, Camel or 1½ Strutter will not be a problem, but that's about it. The answer though should be the Sopwith Bat-Boat of 1913 vintage.
The Sopwith Bat-Boat entered service with the Naval Wing of the Royal Flying Corps in 1913, just before the Admiralty re-designated it as the Royal Naval Air Service, primarily as a patrol craft for the Fleet. Less than half a dozen were built and all varied in design detail, engine type and size and span of the wings. The type was progressively modified including one aircraft being adapted to become amphibious in order to compete in the Mortimer-Singer competition for a series of land and water-borne take off and landings, which it won. This resulted in the German Navy actually buying an example.
But here is not the place for an in-depth appraisal. The most comprehensive coverage and full service history can be found in Aeroplane Monthly - October 1991 issue.
The only kit I know of is this one released by Joystick Models which is a vac-form moulding for the flying boat version but includes additional details and parts for the amphibious version. The first thing one notices when looking at the packaging artwork is an outline drawing of the airframe and frankly, there isn't much to look at, apart from a canoe-like hull and biplane wings. The rest of the aircraft is a mixture of longerons, struts and rigging, lots and lots of it!
The exclamation on the front of the packet "For Experienced Modellers" would certainly seem to be true in this instance. Coupled with single surface wings and tailplane along with a distinct lack of attachment points one would be forgiven for slipping the kit back onto the shelf. But you would be wrong. Firstly, this is an important aircraft and joystick should be praised for tackling it, and, how are you ever going to learn if you don't try!
Just for the record I am a flying boat 'nut' but this is the first single surfaced wing vac-form I have ever built, and only the third rigged in the way described later (I have built more conventional vac-forms though). So if I can do it then so can you! Clear the bench, I feel a vac-attack coming on.
Upon opening the plastic bag one finds a single sheet of mouldings and on holding these up to the light you will see that they are quite deeply drawn. Now would be a good time to back some of them with Milliput to strengthen them and avoid problems later when sanding. A smaller bag contains white metal parts for the engine, an Austro-Daimler 90hp six cylinder water cooled in-line type, propeller, wheels for the amphibious version and other small details. These are very well produced showing a high degree of surface detail. A small but well produced decal sheet gives markings (such as they are) for craft no's 38 and 127. They also include some petite script for the manufacturers stencils.
The instructions consist of two A4 printed sheets, one including titles and header along with a brief history plus technical and colour details. The other has a 1/72nd scale plan as well as references. The plans do require careful study as they are not too clear looking more like multi generation photo-copies so a good number of other reference would be advisable. The multitude of rigging is certainly a good reason for having extra reference material.
Preparation began with marking the outlines of the parts on their carrier sheet with a pencil and then removing them in the traditional manner, scoring around with a sharp blade then breaking away the surplus plastic. The detail moulded onto the wing surfaces is very good, showing just enough to appear realistic under a coat of paint.
Each part is well defined but beware, the plastic is a bit on the thin side (hence the strengthening with Milliput). It would be very easy to crush some of the parts such as the hull. The wings, when removed, require careful handling to ensure that you do not distort them during the sanding process.
Sanding down of the individual was done using the Aeroclub Tee-Al and Sandvic systems, something the kit is perfectly suited for. I had complete control over the parts whilst sanding down and the system was ideal for achieving a very fine trailing edge on the wing surfaces. The system also allows you to get straight leading and trailing edges where required. The tail surfaces were dealt with in a similar fashion.
Once all of the sanding was out of the way it was time to examine what was left. The hull is in two halves, split vertically. Both the upper and lower wings are moulded full span, the rudder is together with the fin, elevators with tailplanes and wing floats each in two halves. These along with two 'bucket' style wicker seats are the sum of plastic parts for the version I was planning to build, no. 38.
Construction was started by adding some interior detail to the hull using various sizes of Evergreen strip and oddments from the spares box. I added a large piece of thick card to the interior of the upper hull which will take the wing mounting points as I deemed this joint to be crucial to the project.
The interior was painted Humbrol Track colour and then washed with Burnt Sienna oil paint, heavily diluted with Turpentine. When this was dry I coated it all with Johnsons Klear wax for a 'mahogany' type sheen. The secret of this method is to leave ample time between the coats and to only brush the oil paint on once. Do not brush it repeatedly as it will dissolve the Humbrol paint. I use a chisel brush for this as it leaves streaks which look like wood grain behind it.
After this the hull was assembled using superglue and a little epoxy. The halves matched well, but all through the building of the model I was worried about the joint splitting, even with card strengtheners inside the hull it flexed to an alarming degree. When the hull has dried out completely it is time to cut open the cockpit opening. Do this VERY slowly as one mistake will be the end of the project. Use a new scalpel blade and make a number of light cuts just inside of the moulded position of the opening. There is not a set guide-line to follow so be careful. Once you are through just work your way outwards taking out small sections of unwanted plastic one at a time. Carefully clean up the cockpit area with the sharp blade, you may not want to sand this area! If you do have to use any filler to correct any slight mistakes don't use Green Stuff as it will eat through the thin plastic.
The seats were then added to the model along with a basic instrument panel and control stick. The exterior of the hull was painted in a similar style to the interior and left aside as I turned my attentions to the wings.
As the wings are single surface, meaning that detail is only carried on one side, the first thing to do was scribe the undersides of each wing to represent the rib positions. This was easily accomplished by laying each one down on my building table, held in place with masking tape, as I ran my scalpel down the edge of a steel rule across the wing following previously made pencils marks transferred from the ribs on the other side.
The bottom wing, when completed, was turned over and positioned on a piece of Tee-Al with masking tape between the strut location points. This ensured that the wing was level. A horizontal line was drawn on the plan across the lower wing bottom which revealed approximately 2 to 3mm of dihedral. I checked this with photos of the full size aircraft and this looked correct so I packed the undersides of the wingtips with card and very light cuts were made at the dihedral break. Further tape was used to hold the wings in position as liquid cement was run into the cuts and allowed to harden. When dry the wing held the correct dihedral.
I opted to build the wings up separate from the hull as a complete assembly so with the lower wings still attached to the Tee-Al I cut lengths of Contrail strut stock to the correct size as shown in the plans and added them to the lower wing, the locations being shown by indentations in the upper surfaces. I made up templates of 90° angles out of spare card and used these to confirm that the struts were vertical, working my way down the wing to check all of the struts. The struts on the full size beast appear to be very slightly tapered but I opted to use the material straight out of the bag and was happy with the result.
When set I painted the inner wing surface and struts as well. I used Humbrol Ivory for the fabric surfaces with gloss Dark Brown for the struts. The Ivory was a gloss paint but once matted down gave me the smooth finish I wanted. The engine mounting points, struts and associated bracing are now added to the central bay of the lower wing, superglue being used for the metal parts. The engine was painted Humbrol Coal Black for a semi-gloss finish, with the struts and bearers being picked out in various shades of Black and Brown. An omission from the kit is the engine mounted upper fuel tank which is very noticeable in photographs. I had thought it would have been included in the white metal components. I built mine after a search through the spares box using a small bomb for the cylindrical portion and capping the end with an odd bit of plasticard. This was then glued onto the top of the engine and painted Brass.
Various pieces of brass wire were added to the assembly to show piping and now I turned to the side radiators! These, on the real thing, consisted of a mass of thin vertical pipes suspended between fatter horizontal pipes, all mounted on the inner side of the engine bay wing struts. now unless you are completely MAD you would not consider the possibility, in 1/72nd scale, of using stretched sprue for this. A close study of the photos shows what a compact arrangement this is, but I thought it was okay for a bit of deception here. I took some spare clear plasticard and scribed a number of lines across it quite close together using a craft knife. They are so close together that any 'fogging' of the card does not show. Then two rectangular pieces were cut out and given a wash of Black oil paint which ran along the grooves, and almost straight away the pipes sprang to life. These assemblies were added to the struts and cross pipes added from the thinnest of Contrail rod I could find. The cross pipes were painted Black and some Copper pipes added at each end, hey presto you have your radiators which really do look the part in this scale.
The underside of the top wing was painted and mounted onto the struts to complete this part of the assembly. This wasn't too difficult applying the glue to two struts at a time and taking care as I made sure that everything was lined up correctly and square. I used epoxy for this as it gave me a little more time to ensure everything was correct but still set but still set in a fairly short time. The empennage and fin were also prepared at this time and put to one side. Now for the tricky part!!!!
FINAL ASSEMBLY AND RIGGING
To build the rear longeron and spar assembly I made a copy of the profile onto a spare piece of waxed card and laid overlong lengths of Contrail rod onto it for the longerons. Then when these had been held down with small pieces of masking tape, I cut the struts from Contrail stock. Again, on the real thing, these should be slightly tapered. When one side was assembled it was carefully removed and another made using the same profile. This way you are certain to get identical sides.
All this time the wings were still attached to the Tee-Al and using this as a firm handhold I decided to attach the the rear 'fuselage' to the wings. I pre-painted the ends of this using gloss Dark Brown and, after trimming to fit, carefully applied superglue to the attachment points for the cross members, then fitted these into place on the longerons. The plans were used for gauging the correct lengths. When this complete 'box' style assembly was completed it was offered up to the wings and glued in place, the empennage assembly was also added to the rear of the fuselage 'box' in the same way. It all seemed a bit shaky at times but as the assembly proceeded the model gained strength.
All of the pre-painting was now finished and at this point I decided to add most of the rigging now whilst the 'fuselage' was still held on the Tee-Al. For this I had considered using the fishing line method to avoid lots of cutting and gluing but I could not be sure that the fragile assemblies would stand up to the drilling and pulling stresses. In the end I opted to use good old stretched clear sprue.
I started pulling over a candle flame a large amount of the stuff and selecting from this the strands which were of a similar thickness. These were hung up with a clothes peg for weight to keep them straight until they were ready for use. By using dividers, and working from the inner bays outwards, each strand was cut just over-length and a drop of superglue placed at a junction of the wing and strut. Once the sprue was in place a further drop of superglue was added. To ensure that the glue went only where I wanted I applied it using a thin piece of florists wire pushed into an eraser end of a propelling pencil, the end of the wire was bent over similarly to a fishing hook which retains a drop of glue.
When you have done a few of the wires they will require heat applied to make them go taunt. At this point six years ago I would have used a cigarette (shame on me!) but having given up the dreaded weed, I looked round for a better way, and found it using in-sence sticks. They burn with a much lower heat and can be cut to length, they also make the house small very pleasant! A packet cost me around £1 and will last for ages.
Working my way around the rear 'fuselage' in a logical fashion I found that the model became much more rigid and had a much stronger feel to it. All the over-length pieces of the rigging had the ends cut with a new scalpel blade and touched in with a dab of paint.
Whilst this had been going on I had applied the oil paint wash to the hull exterior and a final wax coat as before. The wing mounting stubs were added just behind the cockpit, and now the wing/'fuselage' assembly was removed from the Tee-Al to be mounted onto the hull. I was pleased to note that the wing dihedral held perfectly.
The lower wing undersurface and upper wing upper surface were painted exactly as before, allowed to dry, and then the hull and wings were glued together. Card jigs were used, together with the plans, to ensure all remained square. The front hull to wing struts were cut and fitted and the whole lot laid aside to set completely. I now turned to the floats which were assembled and painted. The metal propeller was painted to represent laminated wood. A scratchbuilt beaching trolley was constructed from various Plastruct shaped pieces and scrap card using contemporary photos from the references. I used wheels supplied for the amphibious version to finish off the trolley before giving it a coat of Humbrol and oil paint treatment but using different shades than those used on the hull. When dry the kit was glued to the trolley using white glue so as not to damage the paintwork.
The decals were now added to the fin and these went on without any problems.
The floats were glued into place and almost the final act was to add the propeller, and it was at this point I came across the only snag in the whole kit. The propeller supplied is simply too large. By this I mean too long, by about 3mm or so if one mounts it as per the plans. Having built the wing gap as per the plans the propeller would detach the rear struts on the first time of turning. I did not think to place the prop over the plans as all had gone so well. Having pondered the problem for a while I decided to add it as it was, for two reasons. Firstly, I had spent enough time getting a good laminated wood effect and was not about to chopping up a nice piece of casting, and secondly, I felt it would not really show on the completed model.
The rest of the rigging was now finished, including the aileron guides on the wings. The elevator controls were attached and rigged, and the paintwork touched up where necessary. The last thing was to check all the rigging to ensure it had remained taunt throughout the final phase of construction, and that was that!
Looking back I have to say that Joystick Models are to be congratulated on producing this kit to such a high standard. For the price this kit stands up well against it's competitors and the white metal parts are first class. It wasn't too difficult to build, it just required a different approach to my usual building methods along with one or two new skills picked up along the way.
I now know that having built the model most people can do the same, don't be put off by lots of struts and rigging, just take your time. As for my next project - well the Sunderland can wait until later and I think I'll have a crack at another stick'n'string creation, must be the in-sence!
Sopwith - The man and his aircraft: Harleyfords
Sampson Low Guides - Origins:WW1
War in the Air 1914-18 by G.R. Duvall - pub by Bradford Barton
British Flying boats by G.R. Duvall - pub by Bradford Barton
World Flying Boats by G.R. Duvall - pub by Bradford Barton
Cross and Cockade GB. Vol 15 No.4, Vol 16 No.2, Vol 13 No.3
Aeroplane Monthly - October 1991