Bulldog - control column

Just finished the control column. It's a mixture of brass tube and nickel steel rod, because that's what I had to hand. The spade grip was made by wrapping 0.33mm nickel steel rod around the shank of a drill bit to end up with a tiny helix, then cutting through a few of the turns at once and choosing the best of the resulting pieces. I seem to remember that's how they used to make the links for chain mail.

This is the result. I've got the control column pushed forward slightly relative to the aileron rockshaft, so that I can make the elevators droop a bit when I eventually get round to them:

And that's all the progress I've made this weekend. Not very impressive on the face of it, but it does represent something of a landmark, because the next stage is to do some painting.

But I'm not going to rush into that. First, I've got to decide what paint to use and then I've got to get the hang of using it with an airbrush. So I'm going to have to do a bit of experimentation before making any more progress.

Anyway, more in due course.

 

Bulldog - more work on seat

 After the last post, I realised that the seat wasn't quite right. According to the available kits and aftermarket products, the seat back should have a noticeable taper towards the top. I know, I know. But I thought I might as well go with the consensus.

The next day, I set to to work making a new one. Now that I'd worked out the basic methods, it didn't take too long. But I was a bit hasty with the cutting out, and I ended up with something that was not quite square: the base of the seat was a kind of rhombus, varying in depth by about 0.1mm from side to the other. Not very much, and hard to measure, but the human eye is very good at detecting this sort of anomaly. And it just looked very wrong.

I decided to have another go, and this time make better use of the tools at my disposal. So I drew up a cutting guide in TurboCAD and taped it to a piece of 0.5mm plastic card. Then I cut out the pieces using a steel rule as a guide. In the picture below, the two pieces are separated by a small gap. If you don't have the gap (as I discovered on my first attempt), then when you cut out the second piece, the knife blade can be diverted from its course by the cuts you have already made for the first piece, and you end up with a shape that is not quite as clean as it could be.

Once I'd got the pieces cut out, I cleaned them up and added plastic strip for the sides. This time I made my life easier by adding the pieces and then cutting them to size once the glue had dried. And I remembered to take pictures:

While I was at it, I decided to have another go a the adjustable seat mechanism, using the Airfix 1:48 model as a guide, because I never learn. I ended up with these bits:

But this is where it all started to go wrong. I had a bearer and a sort of tubular framework for each side, but once it came to gluing them together, I took my eye off the ball. In order for the seat to sit properly on the framework, the bearers have to be exactly aligned, but somehow I got one of them almost 1mm out vertically from the other. Also, the struts were much too big and so the seat ended up much too high. I know the seat was adjustable, but even so...

 

I had a couple of hasty attempts at putting things right, but in the end I decided I would have to have another go at the mechanism, and so I called it a day.

 

Next day, I redrafted the mechanism and set to work rebuilding it. For the previous version, I had used 0.4mm Plastruct rod, but I had run out of this, so I used 0.5mm Evergreen instead. I had the feeling this would be a bit over scale; but on the other hand, it was bound to be stronger. As before, I printed out an assembly jig and taped the plastic rod to it as I went along. But this time, I added the bearers before cutting to size.

 

After this, I cut along the baseline of the seat using a guillotine (I forgot to take a picture), and this is what I ended up with:

Then all I had to do was glue the bits together and add the adjustment lever. The lever was made from 0.4mm Albion Alloys brass tube, with 0.1mm nickel rod inserted for the release button. Unfortunately, because I cut it to something like scale length, I don't think you're going to be able to see the button.

 

The next thing was to do a trial fit.

And unfortunately it didn't fit.

The problem, as I discovered, is that the adjustment gear fouls the diagonal cross-bracing at the rear of bay no. 2, and this is probably one result of the compromise that had to be made between scale dimensions and the thickness of the fuselage mouldings. I think a further compromise will be necessary. In all probability, either the cross-bracing or a part of the seat mechanism will have to go. But rest assured, I'm not going to do anything hasty, especially since I've already poured myself a well-earned glass of cab sauv.

But one outcome or other soon!

 

Update: in the end, I removed the cross-bracing. It came away quite easily with just a bit of tweaking so that's a relief. The seat still doesn't fit exactly - the top edge comes up against the bulkhead and so prevents the whole seat from tilting back far enough. As a result, the bearers don't quite meet the cross-strut at the back. But the gap is less than 1mm, so nearly there! If necessary, I could shave a bit off the top of the seat back. Or I could decide that I don't actually mind the gap. More on this later probably. There's no great hurry.

Bulldog - Seat

 I've made a start on the seat. Once this is done, it's time for a batch of painting. Then I can start putting everything together. I still have to decide what paints to use, but more on that later.

 The first thing I tackled was the headrest, or rather the bulkhead that the headrest is mounted on. I just carved this from plastic card with my usual trial-and-error technique. As usual, this seemed rather a hopeless task to start with, but in the end it went quite well and I got quite a good fit. I decided to carve the headrest itself separately and add it after painting, so the only other detail to attend to at this stage was the slot for the Sutton harness. This turned out to be pretty simple to do. I just drilled a central pilot hole, then used the same drill bit as a sort of file or router to open it up into a slot, with the result you see here:

This is one item that can be sensibly be treated as an integral part of the fuselage framework, so I've cemented it into place, and this is what it looks like:

 The next job is the seat itself, and this is where it gets slightly difficult. My main printed reference (David Luff, 1987), says that the seat was adjustable, and provides some useful details of the mechanism, but I can't find any photos or diagrams of the seat or the adjustment gear. So in the end, I have had to fall back on existing products. I seem to remember that I warned against this in my previous post, and I am aware of the danger that I will end up effectively making a model of other models; but this is a risk I will have to take in this case.

What I ended up doing was studying the online instructions for the Airfix 1:48 Bulldog and then trying to build something that represented what the Airfix kit is trying to represent. It would have been nice to effectively reverse-engineer the Airfix moulding to understand the workings of the mechanism. But in the end, I just decomposed it (as we say in software engineering), to end up with a set of individual parts that look like this:

 

 I think it should look reasonably convincing once it's in place. But that's enough for one day. More soon.

Bulldog - more work on instrument panel

 I finally decided to correct the opening for the compass. My idea was to plug the hole with plastic rod, cut it flush and then drill the new hole, in the right place this time. I wanted to avoid any type of filler, because I knew this would just flake away when I started drilling. But I was pretty sure that a plug of plastic, cemented into place, would be as strong as the original card.

I tried it on a piece of scrap plastic card first, and it worked perfectly. So I went ahead with the instrument panel, and it worked perfectly again. Phew.

This is the result:

 I also decided to add a bit more detail before painting, particularly the boost gauge and the metal box that I assumed was the map case.

To start with, I had assumed that the boost gauge was mounted on one of the uprights of the fuselage framework. But my internet searches turned up pictures of an aftermarket instrument panel that had the gauge hanging off the instrument panel as though on a bracket. In the absence of other information, I decided to follow this example But then, after starting work, it occurred to me to return to my main printed reference (David Luff, 1987), and actually read some of the relevant sections. Previously, I had skimmed over these and relied mainly on the diagrams and photos (which are invaluable). Anyway, in Chapter 3, he provides the answer. The boost gauge was mounted on the port side strut of frame no. 2. So I tore off the improvised bracket I had made. The gauge will have to be added to the framework after painting. Fiddly, but not too difficult. At least I have an answer.

 I still had to decide about the map case, and here my closer reading of David Luff paid off again. It was a combined map case and diagram box, as it turns out, so I was pretty close.

It was pretty straightforward to model: a piece of plastic strip sawn to length, with a length of 0.3mm nickel steel to show the hinges on the front. (I think they're hinges.) I had to make a guess at the depth, but my map case came out at about 3x4mm or pretty close to A4. I imagine there's information available about the size of maps used by RAF pilots in the 20s and 30s, but this is a reasonable guess I think.

I still wasn't clear how the box was mounted, but I decided to use a simple bracket made out of plastic strip. Later on, the instrument below the panel will be added to this. And on this subject, Luff came good again. It was a Schilovsky-Cooke turn-and-bank indicator.

So here is how the instrument panel looks now:

 Incidentally, what you tend to see in kits and aftermarket products is pretty much just the front of the map and diagram case. In reality, I expect that it would have extended back a bit further to accommodate the maps, and that's what I've shown. But that just illustrates the hazards of relying too much on existing products instead of historical sources.

Anyway, that's all for now. More quite soon.

Bulldog - instrument panel

 This is a job of two halves: one much more fiddly than the other, and the other much more fun. First of all you have to cut out the instrument panel itself and make it fit inside the fuselage mouldings, then you have to add the instruments and various controls.

You can probably work out which stage of the job is which.

When it comes to making the basic panel shape, one obvious solution comes to mind: you get an impression of the fuselage with Plasticine, and then just draw round it on a piece of plastic card and cut out. But Plasticine is rather a blunt instrument for forming a tiny part like this, and it would be difficult to get an accurate outline. I think there are purpose-made moulding compounds available now for doing this kind of thing, but I decided just to do it by trial and error, using the following rather ad-hoc technique:

1. Cut out a rectangle of plastic card the right height, that exactly matches the width of the framework.
2. Cut little rebates so that it drops into place (this matches the design of the original)
3. Roughly shape the panel
4. Repeatedly, slot it into position into the framework and offer up to one fuselage half or the other, until it fits exactly

And this, as you will have worked out, is the fiddly bit. One of the problems is that it's difficult to hold the panel in place as you do the fitting. Another is that it's easy for the panel to push the framework out of position when you're doing the fitting, so you think you've got a good fit but in reality the panel is still too large. You've got to be on the alert for this.

Here you see the fitting in progress. You might notice that somewhere along the way I've added the engine bay bulkhead, with a location tab so that the framework just drops into place. This makes the whole test fit procedure much easier and less error-prone.

 And in the end, I got a reasonably good result. This is the basic panel I arrived at:

At this stage, I can be fairly sure that the starboard side is a pretty good fit, and the whole thing is the correct width because it fits into the framework. When it comes to final assembly, I will glue it into place in the framework and then glue the framework into place on the starboard side. Then, when everything is set, I can do a bit more shaping if necessary to make it fit the port side.

So, onto the fun bit.

I have decided to use a two-pronged approach for attaching the instruments and controls.

1. For the larger ones (above 1mm), cut discs of plastic rod and sand them between two pieces of wet and dry. Then cement them into place.
2. For the smaller ones, drill a location hole, push through a length of plastic rod and then cement on the reverse side. When all is set, trim off the excess. To neaten up the ragged cut end, either sand down or just douse in liquid poly. I can decide later about that.

 Also, the build will be a two-stage process. The panel and most of the instruments had a black finish, so I can do all these in one go before painting. Some other things like the brass switches I'll add after painting.

Here is the panel almost ready for painting:

There are still a few additional bits to make:

1. A compass, to be mounted behind the circular cut-out
2. An instrument to be mounted below the panel (an inclinometer?)
3. A boost gauge, to be mounted on the framework
   

 You may notice that the cut-out for the compass is slightly off-centre. I will have to decide whether to do anything about this. I certainly don't want to start again.

Anyway, one way or another, more soon.

Buldog - rudder bar assembly

 I've finished the bits and pieces for the rudder bar assembly.

I wanted to represent the corrugations in the heel troughs. The obvious way to do this is to score a series of parallel lines on a piece of plastic card. To be true to scale, though, there would have to be 6 or 7 scored lines in a space of about 2mm, and I couldn't think of a way of doing this while keeping the spacing regular. But bearing in mind that nobody will be able to see the finished result, I decided to just do a few scored lines by hand. I had a few goes on a piece of plastic card and then when I had got something that looked reasonable, I cut a strip the right width and added side walls from plastic strip, with results very much like this:

I made a single long piece, as you can see above, and then cut off lengths with a guillotine:

The rudder bar is just 0.5mm plastic rod, with tiny little strips of brass sheet bent to shape for the toeholds. The brake pedals are slices of 1mm plastic rod, sanded down between two pieces of wet and dry, and then attached to small lengths of plastic strip. The bits for the adjusting gear are a mixture of plastic card and metal rod (nickel steel and brass).

Here are all the bits, waiting to be painted and assembled:

 Next, the instrument panel. I'm quite looking forward to it.

 

Bulldog - armament

Now that I've made the framework, and got it to fit into the fuselage, I can start adding the other details. Because I've opened up the gun troughs, I need to make Vickers guns to slot into them. And this is also a good time to build the ammo boxes.

The guns will hardly be seen, so I kept them simple. I cut pieces of plastic strip, 0.75x1.5mm, and drilled 0.8mm location holes at the front. Then I cut lengths of Albion Alloys 0.8mm tube for the barrels and glued them into the location holes. I added a tiny bit of 0.4mm square strip bent into shape for the loading handles, which I've decided are Hyland Type B in the absence of any other  information. And that's pretty much it. You won't see the barrels,except for the muzzles, because they are hidden by a louvred cover, so there's no need to represent the perforations in the jackets.

I was in two minds about the ammo boxes. I thought of cutting them out of plastic card, and got as far as designing the outline in TurboCAD and printing it out. But then I thought better of that idea. It would be almost impossible to cut out the shape neatly. In the end, I just built up the shape from various thicknesses of 1.5mm plastic strip; and for the curved interior corners I just pasted on some Milliput and smoothed it to shape with the shank of a drill bit.

Here are the results:

Not too bad.
 

Bulldog - fuselage framework

 After all that scraping and drilling and general removal of material, at last it's time to start building. And the first thing to build is the fuselage framework. All the other interior detail can be mounted on this.

I seem to remember that on previous projects, I've done this in rather an ad-hoc manner, with a lot of pins. But this time I decided to make things easier for myself with a basic jig. This involved the following steps:

1. Import diagrams of fuselage structure from my reference source into TurboCAD
2. Scale
3. Print out two copies
4. Mount the copies onto thin card, approximately 0.5mm thick, using PVA glue
5. Cut out one copy. This will hold the fuselage structure in place while you're building it up. At this stage, I had to make a decision about the fit. If I made the structure full size, it would not fit into the fuselage because of the thickness of the fuselage halves. I decided to reduce by 1mm vertically because this would just involve cutting along the inner edges of the longerons in the diagram (each approximately 0.5mm in width).
6. Mount this onto the other copy. The lower copy will provide a guide for the placement of the upright struts.
   
7. Mount the whole thing onto a block of MDF, to prevent any curling or wrinkling.
   

This is what I ended up with:

 The framework of the Bulldog was mainly constructed from 1.25" steel tube of one type or another. This corresponds to 0.44mm at 1/72nd scale, so I decided that Evergreen 0.5mm rod would do the job nicely. I bent two pieces into shape for the upper and lower longerons, taped them into place and then set to work cutting out tiny pieces for the uprights and gluing them into place with liquid poly (Slater's Mek-Pak - it has served me well over the years). This is how it looks in situ:

 Then in theory you just pop it out and get a perfect fuselage structure profile; and then repeat for the other side. But in practice, it's surprisingly difficult to get the two sides to match exactly. The thickness of the printed lines allows a certain amount of latitude when it comes to placing the uprights and so you can end up with discrepancies of 0.2mm or so. In the end, I did three frameworks and chose the two that best matched. As you can see, I discarded the one marked B:

 The next step was to build jigs for the plan views, upper and lower, and to assemble the two halves by adding cross-pieces. Again, I made a guess at the reduced width and cut the jigs accordingly:

Then I taped the framework into the fuselage and tried it for size:

It was much too small: there was a 0.5mm gap on the opposite side. So I had to start again. This time, I cut jigs that corresponded to the full width, and it came out almost perfectly. So what it amounted to was that the framework was scale width and 1mm below scale height. Perfectly acceptable. At this point, I could add a few final details such as further cross-bracing and this is what it looked like:

 Looking pretty good so far on the whole. More soon!

 

Bulldog - Work on fuselage

I decided early on that I was going to add a bit of interior detail. The kit doesn't really have any, except a seat and a pilot and a sort of notional cockpit floor. But I decided to follow the example of the newer 1:48 Airfix release by building up a section of the framework and dropping it into place. So a bit of prep work was needed before I could do that.

Also, I decided to add some detail to the fuselage itself, mainly by cutting out apertures here and there. This always helps to bring the model to life and to counteract the impression of a solid lump of plastic. The main features bringing life in this way are:

• Cartridge ejection ports below the gun breeches
• Link ejection ports level with the gun breeches (I think that's what they are)
• Gun troughs
• Handholds at the rear of the fuselage
• Openings to the rear of the tailplane. These seem to accommodate the rear spar of the adjustable tailplane.
• Vents at the rear of the engine bay
• Openings for the plumbing of the Vickers Potts oil cooler
• Various new location holes (some of the existing ones will get filled once the fuselage halves are glued together). 

I ended up carrying out both these jobs in parallel and alternating between the two.

And then, there was the question of panel lines. The kit has raised panel lines, and ideally they should be rescribed, but I'm not very good at this and was reluctant to try it, so I had a bit of a conflict on my hands. You can see the result of that conflict below.

Anyway: to work!

Before doing anything else, I needed to remove the location lugs for the notional floor moulding. In the photo below, I've made a start on the port side.

After this, I sanded down the interior to try to reduce the thickness of the moulding a bit. I was going to have to reduce the size of the framework slightly to make it fit, but I wanted it as close to the scale dimensions as possible. At this stage, I also started opening up some of the apertures, particularly the cartridge ejection ports. This helped me gauge how much thickness was left. (Holding the pieces up to the light helps as well.) Here you see the process under way. The starboard side is further advanced than the port side; look how nice and thin it is at the cockpit opening.

When most of this work was complete, I decided I could not put off the question of the panel lines, and so I took the plunge. I decided to start with the access hatch for the W/T equipment and then review progress. But fundamentally, I was not convinced it was a great idea, so the following ensued:

1. Started out with the wrong frame of mind
2. Didn't take much care planning how I was going to do it and just plunged in
3. Made a mess of it
   

 There were a couple of obvious choices after this:

1. Fill the gouged-out panel lines and try again. But in my experience, if you try to do this, the filler just flakes off when you try to scribe over it. At least, this is what happens with Milliput, which is what I always use.
2. Buy another Bulldog, and start again with the port fuselage half. But this would be wasteful, and perhaps go against the spirit of building my Christmas present.

In the end, I went for another option: cut out the access panel and make another from card. Pretty drastic, but then again (I reasoned) I could always fall back on option 2 above, Christmas or no Christmas. This is the what it looked like after the initial butchery:

 

Then neatened up:

With new hatch cover in place:

Phew! I think that's just about OK.

This is what the fuselage halves looked like at the end of this stage. You'll see I also fabricated the little panel near the link ejection port on the port side. It's well above scale thickness, but an improvement on the moulded item.

Anyway, that's enough excitement for one post, I think.
 

Bristol Bulldog - IIA or not IIA?

 The first question I'm facing is which version to build. It seems that the IIA was the main production version (268 built according to Wikipedia), and so that's the one I'm going with. The Airfix kit also represents the IIA, which is a good start, but then there is the fact that several alterations were made to the IIA during production, and so I need to decide fairly early on which particular aircraft or at least which batch I am going to build.

The main alterations (that will affect a model at this scale) seem to have been as follows:

• Oil System: the Mk. II oil tank was mounted on the underside of the fuselage, with cooling vanes. In the Mk. IIA, it was moved to the upper side of the fuselage, and an external Vickers Potts cooler was added to the underside. The Airfix kit has cooling vanes and also the external cooler. The restored IIA at the RAF museum at Hendon has the external cooler and a plain aluminium panel, with no cooling vanes.
  
• Fuselage: circular access hatch added to the underside. This is shown in the Airfix kit.
• Tailskid: replaced with a tailwheel. The Airfix kit includes a tailskid.

Then there is the question of fuel lines. My main reference (David Luff), has a photo on page 100 showing aircraft of 41 Squadron with four fuel lines. The restored IIA at Hendon also has four fuel lines. I'm not sure if this was a feature of the Mk IIA or some special adaptation.

Anyway, here is my plan:

• Sand off cooling vanes. Add pipework to the external cooler provided with the kit (which is quite a nice moulding), and remove location lug. Drill out holes for the pipework. Fill the original location hole.
• Maybe add a bit of detail to the access hatch, by drilling out and then adding the hatch cover from plastic card.
• Decide later whether to have a tailskid or tailwheel. For instance, I could have a Bulldog from 41 Squadron, with a tailskid, or one from 32 Squadron, with a tailwheel.
• Decide later whether to have four fuel lines. I might have more information by then.

I think that's enough to be going on with. I am happy to be corrected on any of this waffle, by the way.

A Bulldog is not just for Christmas, or lockdown for that matter

 A while ago, I started a scratch-building project and recorded its progress in this blog. Since then, I have been meaning to get on with another project, but have never quite got round to it. Then, for Christmas 2020, my brother sent me an Airfix Bristol Bulldog, probably for something to do during lockdown. In that spirit, I was planning to build it straight out of the box, but when it came down to it I couldn't quite bring myself to do that, and I couldn't quite find the time to make a proper job of it. Anyway, a few years later, I have finallly made time and made a a start.

The box art in this issue is by the late Roy Cross:

And this is what you get in the box (there are transparencies, but I seem to have lost them):

And this will be my main reference (I got it used from Amazon, ex Nottingham Central Library):

 

Incidentally, when I logged in to create this post, I noticed that the last one was in 2013. Scary how time flies. Must get a move on. Also, I remember predicting at the outset that this blog would soon outlive its title, and so it has proved, because this Bulldog will have the classic interwar aluminium finish. But if all goes well, I will soon be mixing up a new batch of PC10 for some new project.

More soon.