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Britannia 70018 Flying Dutchman

This is another hybrid, having a Hornby body and a modified Comet chassis. It is running on Alan Gibson wheels with Mashima motor and High Level gearbox.

4114

 

Building the Model

The Body

airfix

Although the body is one of the best produced by Hornby, there were changes made by BR(W) to be incorporated as well as a few extra details to be improved or added.


changes
Fig 1 Left hand side alterations and additions


The first things to come off were the smoke deflectors [A]. On the model, these were the original pattern with handrails. Following a serious accident near Didcot in 1955 the Western Region decided to alter the deflectors as it was felt that the handrails restricted the drivers’ visibility which was a contributory factor in the accident. Suitable replacement etched nickel silver deflectors were obtained from ‘Judith Edge’. These were made up and air brushed, new name plates fixed and then set aside for fitting later.
It was also decided that the Ejector Exhaust [B] was also a liability and the Western duly lowered the position of this. The moulding was eased out of the body and refitted in a hole drilled in the body a little lower down. The old hole was filled and new pipework/conduit was made up with fine wire as well as a representation of the solenoid valve that BR(W) added at the same time.   See Fig. 1a.

1a

Fig 1a Ejector Exhaust before and after changes


The earlier members of the class had additional supports added to the Front [C] and Rear [D] Regulator Rods to combat vibration. These were fitted to later locos from new. They are not on the Hornby model, so were added with small sections of black styrene, secured with super glue and touched up with BR green paint.
When I came to match up the chassis with the body, it became apparent that the hole [E] in the valance, to access the lever on the lifting arm on the reversing gear, was too far forward. This was duly filled and touched up and a new hole cut out further back in the valance. This hole was drilled then opened up to the correct shape with a scalpel.
Raised fillers [F] to the sandboxes were added from 1953 onwards. These are very simple objects requiring just two small pieces of black styrene, secured to the footplate with solvent. The pipes connecting them to the front sandbox are attached to the underside of the footplate. As the front sandbox is not visible, it has not been modelled. The rear pipes and sandbox are attached to the chassis and detailed later.
The Hornby model has the AWS warning system fitted whereas the Western engines had ATC. The cabling and footplate mounted battery box were removed. A new cable [G] was mounted the full length of the left hand valance and a new battery box (black styrene) [H] was fabricated and fitted under the cab. The Hornby model has some large cable brackets forward of the cab. These were removed and the holes in the valance filled. New smaller brackets were then fitted. All these small mods were carried out carefully as I did not want to have to repaint the whole loco! See Fig 1b.


1b

Fig 1b New ATC cable and battery box. Note where two small cable brackets have replaced three large ones

Hornby didn’t quite get the firebox and ash pan quite along with all the various bits of pipework and fittings thereon. I think one of the reasons for this is that the cab side is too short as it should project below the valance by another millimetre. It’s possible that everything in this area was therefore set out from an incorrect datum. This came to light firstly when adding extra bits and pieces to the side of the firebox and latterly when I wondered why there was such a large gap between the underside of the cab floor and the tender. Maybe it had something to do with clearances over the Hornby trailing truck. Whatever, I wasn’t going to start carrying out major surgery, so I filled in some of the ‘daylight’ with black styrene [J] and raised the tender under the cab by 1mm, sprinkling a bit of coal on it for good measure [L]. This makes the whole thing look a lot more ‘solid’. I also packed out the firebox to fill the gap between it and the chassis, again with layers of black styrene secured with solvent before trimming to shape and smoothing off. This can be seen in Fig 2a.
One of the changes on the firebox was to remove a moulded on pipe and replace it with one in the correct position for 70018 [K]. This can be seen in Fig 1b.
I drilled out the openings in the supports [M] to the cab floor to make them look more convincing. As the underside of the floor is moulded to the profile of the supports over its full width, I drilled them reasonably deep and painted the inside of the holes matt black.
The glass deflectors [N] between the windows had gone missing so I made replacements, adding a bit more detail to replicate the hinged frame while I was at it. See Fig 1c.


1c

Fig 1c New glass deflector and frame

Pipework was added between the loco and tender from brass rod [O].
An AJ coupling was fixed to the rear of the tender [P] as were a pair of guard irons [Q]. Screw link couplings (Exactoscale) and hoses (brass wire wound with fine copper wire) were fitted to both loco and tender as were BR(W) style lamp irons (left-overs from various kits) to replace the moulded on ones which were carefully removed with a scalpel. When fixing lamp irons, I drill out one rivet and solder in a short length 0.3mm brass wire. The outer end is filed down to represent a rivet head and the other end used to pin the lamp iron to the plastic bodywork.
Shortly before weathering the loco, I noticed that the chimney [R] was a bit crude, so I got to work with a couple of needle files and soon had it looking a lot more like the real thing. See Fig 1d.


1d

Fig 1d Chimney before and after

After weathering, flexible draught screens [S] between the cab and tender were fixed to the tender with super glue. These were made by folding up black tissue paper to form a concertina. Needless to say these are very vulnerable to damage and care is needed when handling loco and tender. They only take about five minutes to make so can always be renewed if necessary.
I also noticed that there was a small gap between the top of the sludge collector [T] so this was filled with a thin strip of black styrene and weathered in.

Turning to the other side of the loco …


2
Fig 2 Right hand side alterations and additions

Photographs show a pipe [U] leaving the smoke box and disappearing below the footplate. I don’t know what this is (I’m sure someone will tell me) but I decided it needed to be there on my model. This was made from soft copper wire soldered into small strip of nickel silver filed to shape to represent a pipe flange and secured with super glue in a hole drilled in the smokebox.
The cable operating the chime whistle was carried inside the tubular handrail. I have modelled it between the handrail and the cab using fine copper wire [V]. I also added a few other bits of small conduit/pipe running on the firebox [W].
The exhaust steam feed to the injector has also been extended and can be seen dropping back down between the frames [X]. A small diameter pipe [Y] has also been attached to the exhaust steam feed pipe. All this work was fabricated from brass wire and shim. An ash pan operating lever [Z] was fabricated from brass strip and pinned to the side of the firebox. See Fig 2a.

2a Fig 2a. Exhaust steam feed pipe and ash pan operating lever.


There were also some basic modifications to carry out on the underside of the body, see Fig 3. I have used the original Hornby mounting at the front but have introduced a new one at the rear. This is basically a 10BA bolt soldered to a piece of n/s sheet and secured to the bodywork with epoxy. It turned out to be slightly high, hence the black styrene packing piece! The bolt is also sleeved to take the tie bar from the tender. There is a lot of lead in the boiler as well as in the firebox. The lead was weighed and carefully positioned so that the centre of gravity was over the centre diving wheels. Fig 3 also shows how the hoses have been soldered to a strip of PCB and secured in place with epoxy. The false bottom to the boiler was made up of laminations of 0.25mm thick styrene sheet over 1.5mm thick styrene formers. The hole in the middle is to clear the retaining nut on the motion bracket (see later). The photo also shows the front sand box feed pipes, the extension to the exhaust steam feed pipe and the packing to the inner faces of the firebox. I did fit bracing to the front steps (see Fig 14) but they were very vulnerable and eventually got knocked off when fitting and removing the chassis. Very late in the day I soldered new bracing onto the chassis which was a much better solution. With the chassis in place, the springiness of the n/s strip holds the braces firmly against the back of the steps.


3
Fig 3. The somewhat less than tidy underside of the body


I also had to carry out a few repairs/replacements. These included a broken step on the tender and a new chime whistle filed up from a bit of brass rod.
Nameplates and shed code plates came from 247 Developments. Replacement cab side number 8 from HMRS. The nameplates came with red backgrounds, these were changed to black. It was not too difficult to change the smokebox number from 0 to 8 with the tip of a scalpel blade and a little white paint.


Modifying the Chassis

The chassis is an etched nickel silver kit from Comet Models. This is the 'upgraded' version suitable for building in 00, EM or P4. Marrying up bodies and chassis from different sources is not always straightforward. A third element to enter into the equation is the prototype. There was no way that I was going to make any visible alterations to the body (other than those mentioned above) so any necessary corrections would have to be made on the chassis.

I made detailed measurements of both body and chassis and drew them up in Autocad to highlight any obvious clashes. I had no GA's of the prototype so I extrapolated dimensions from photographs using wheel centres as a base line. For this, I referred to two books from Irwell Press: The Book of the Britannia Pacifics and The Book of the BR Standards:2, as well as an article by Allan Sibley in MRJ Compendium No.1.

This operation highlighted the following immediate problems:

1. The cut outs for the cyliders were too far back and too deep.

The cut outs were extended forward using a piercing saw. I overdid this as I had not at this point apprciated problem no.2! However, when it came to precisely positioning the cylinders, I fabricated a plate the full size of the opening that was then soldered to the underside of the cylinder assembly. This also cured the second half of the problem!

2. The whole chassis sat too far back in relation to the bodywork. This was part of the cause of the first problem and is probably due to the fact that the drop in the footplate is moulded to the full thickness of the valance on the body.

There is not enough material to reduce the sloping front edge of the side frames, so I resorted to chasing grooves in the bodywork. Being over thick in the first place, this was not a problem.

3. The wheel centres were not at the correct height. This could have been a result of providing side frames that were deeper than the prototype.

The wheel centres were removed and hornblocks used on all axles even though the rear axle would be 'fixed' as part of the proposed compensated suspension.

4. The front ends of the side frames were a little too high.

Easily filed down.

5. The cut out at the rear of the side frames was not deep enough to accommodate a mounting plate.

Again, there is insufficient material to reduce the side frames so the body was modified accordingly. The cut out in the bodywork also needed increasing in width to accommodate the P4 frame spacing. This seems a good point to mention frame spacing! the prototype had the narrow frames to place them over the centre line of the hornblocks and this could be replicated by using narrower frame spacers. Unfortunately, this would not have left enough room between the frames for my chosen gearbox!

6. The main springs were far too narrow.

The offending items were removed with a piercing saw. Overlays are provided in the kit; the hangers were removed from these with a piercing saw and soldered in the correct position on the inside face of the side frames.

7. The etched slots in the side frames for the motion and lubricator support brackets were not the correct depth to match the brackets provided in the kit.

Those that were too shallow were deepened with a piercing saw. Those that were to shallow had a support plate soldered to the inside of the chassis.

8. The cut-outs to clear the bogie wheels were far too large.

Fiiled to a more suitable profile with styrene.

Other problems became apparent during construction and these are dealt with below.

Prior to assembly of the frames, decisions had to be made about the bogie and the pony truck as the design of these would affect the location and orientation of of the frame spacers. There is no tab and slot construction on Comet kits, so, although they give guidance as to the location of spacers, the final choice is up tp the builder. I opted to pivot the bogie (using most of the Comet etches) as per the prototype, likewise the pony truck. I was lucky that a friend, Mike G, had already designed an etch for the pony truck and he kindly sent me a pre-production version so that I could establish the exact position of the mounting. In positioning the spacers, I also had to take account of the mountings for power collection from the wheels and the space occupied by the compensation beam and its pivot. This is where time spent planning on the computer pays dividends. Finally the choice and orientation of the motor/gearbox had to be taken into account.

Assembly

The first parts to assemble were the coupling rods as these are needed to set up the chassis jig. I decided to try and make forked connections (as per the prototype) using the components on the etch (designed to be rigid or articulated on the crank pin). While the first one was successful, I decided that it was a bit fragile so decided to start again. Fortunately, I was able to use the other coupling rod (still on the etch) as a master to cut a new one out of n/s sheet.

This time I made a lapped joint but articulated the coupling rod as per the prototype, not on the crank pin. To do this, everything has to be turned back to front. The Comet coupling rods come in three pieces: a rigid backing piece and two half etched front pieces. The backing piece has a half etched break point for articulation. This break point is ignored and the rod separated as per the prototype. These now become the outside face of the rods with the redundant break point to the rear. The half etched front pieces now become the backing. I used the fluted rods for extra strength. Prior to separating the rods, a complete one was used to drill three holes in a block of hardwood. Drill bits placed in these holes were then used to locate the parts when laminating the rods. As the loco carried plain rods, the bosses at the front were built up with brass shim (I didn't have any nickel silver that thin) and the depth of the top webs of the fluted rods at the back were thinned down a bit. The (now) rear rod has a half etched representation of the articulated joint which weakens it a its most vulnerable point, so a small shim was soldered over this. The joint was made with a brass pin with the head filed flat. I also countersunk the front face of the rod slightly so that the pin sat well. The pin was then soldered at the rear and filed down flush with the adjacent afore mentioned shim. For the soldering process, I separate the two halves of the joint with a slip of tissue paper soaked in clock oil. This can be teased out afterwards and gives a little lateral flexibility to the joint. I subsequently had to reduce the thickness of the front bosses on the coupling rods to match the Ultrascale bushes on the crankpins. This is not shown on the photo below.

rods

Prior to assembling the chassis, the side frames were modified as detailed above and holes were drilled for the compensation beam pivot. The centrelines of the axles were scribed on the frames as were the exact positions of the frame spacers. With the first side frame in place on the jig, High Level hornblock guides were soldered in place, followed by the frame spacers which were located as shown below. This assembly was then replaced on the locating pins by the second frame and the hornblock guides were soldered in place. The other frame was then dropped onto the pins and the spacers soldered to the second frame.

frames

1 is the front body mounting

2 is the mounting for the cylinder assembly and has a 10BA nut soldered to its lower face

3,4&5 are for the PCB strips that will carry the electrical pick ups and have 12BA nuts soldered to their upper sides

6 is the mounting for the pony truck and has a 12BA bolt soldered in place

7 is the rear body mounting

A is the mounting bracket for the lubricators and was soldered in place once the corect height had been established.

B is the motion bracket.

bracketbracketThe frame spacer (4) intended to support this would have clashed with the compensation beam, so the spacer was modified accordingly. The motion bracket was reinforced with 3x1mm brass tube drilled to take a 12BA bolt. The brass tube has the ends recessed to sit between the frames and locates the bracket centrally over them. It is secured to a 12BA bolt soldered into an inverted 3x1mm brass channel section soldered between the frames. This enables the motion bracket to be removable. I have also added a bit of extra detailing on the LH motion bracket to make it look a little more like the prototype.

The final mounting plate is for the front bogie.

bogie mountThis was cut from 0.45mm thick nickel silver plate, reinforced along its edges with 1x1mm brass tube and soldered across the underside of the frames between the cut outs for the bogie wheels. A 10BA bolt was soldered in place prior to fixing. This is sleeved with a short length of brass tube which provides a pivot along which the bogie can slide laterally.

 

 

 

Compensation beam

beamThis was designed to bear on the front and middle axles and comprises two sides cut from scrap n/s etch. The spacers at each end were made slightly over long so that they could be filed to the correct height once all the wheels/axles were in place. The 2.35 o/d brass tube rotates on a 1.5mm dia brass rod.

 

Setting the height of the rear axle

adjustTo enable the height of the rear 'fixed' axle to be set accurately, lengths of 3x1mm brass angle were drilled for 12BA bolts. Nuts were soldered in place and filed to be flush with the edges of the angle. These assemblies were then soldered to the side frames, sitting on top of the hornblock guides. 12BA bolts are then used to set the height of the hornblocks.

contd......

 

 
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