Sopwith Dolphin - radiators

I've spent the last few days making radiators. I wasn't going to originally. I've got a resin kit of the Dolphin, and my original intention was that the radiators were the only bits I was going to use from it. But when I looked at them closely, I saw that they were, to be honest, little more than blobs. So, as I said to myself more than two years ago when I first got the resin kit, I can do better.

Sopwith Dolphin - seat finished

At last, I've got the seat finished, and here it is:

Sopwith Dolphin - Wings

At last, I've got round to doing some more work on the Dolphin. Before finishing off the fuselage, I thought I'd try to work out how I'm going to make the wings. There are two main features of the wings that are going to be tricky to reproduce: the camber and the aerofoil section. And I don't just have to get it right once: I have to make four of them, all identical.

Sopwith Dolphin Retrospective No. 9 - Fuselage nearly finished

Now that I had got the engine in at last, I could add some final detail:

Yep, that's what 0.0005 horsepower looks like

Sopwith Dolphin Retrospective No. 8 - Project Saved

The project saved

Sopwith Dolphin Retrospective No. 7 - The Engine

The engine for a Dolphin I was a geared Hispano Suiza; which I'm hoping looked very much like this:

The original generated 200hp, apparently, and I remarked to someone, in a jocular manner, that my 1/72nd scale replica would therefore develop 2.8hp. But this can't be right, can it? A model 3 inches long having the power of almost 3 horses at its disposal? That would be simply crazy.

Sopwith Dolphin Retrospective No. 6 - More Fuselage Clutter

Next: the instrument panel and all the clutter behind it.

 I spent a lot of time studying Windsock 54 and the Cosford pictures before doing this bit. It looks as though there was a bit of variation in the layout; it probably depended on the variant. But the Cosford version looks like the Dolphin I, with its geared Hispano engine, and that's the variant I'm making, so I'm probably not too far off.

Sopwith Dolphin Retrospective No. 5 - Rear Decking

Here's how it looks with the rear decking:

The problem here was to represent the effect of canvas over longerons. I knew I could forget right away about trying to carve or mould my way to a decent result, but I thought that a sheet of plastic card, scored on the reverse, might do the trick. I think I've seen this technique mentioned somewhere before. So I tried it out with a bit of scrap and it works a charm. The scoring actually serves a structural purpose in addition to what you could call its mimetic purpose, though the two are closely related. At this scale, a piece of card just doesn't want to conform to a roughly conical surface; but after scoring it curls up like a little kitten.

Sopwith Dolphin Retrospective No. 4 - Interior Detail

This is the fun bit, isn't it? Yeah!

Sopwith Dolphin Retrospective No. 3 - Vac-Forming

Vac-forming is never going to give very precise results with the sort of home-made equipment I'm using, but the key is to be aware of its limitations.

For instance, an injection-moulded kit might represent the forward decking as a single piece, with the fairings for the cylinder heads moulded integrally, but that would never work with my simple techniques. So the fairings have to be moulded separately. And there's no point trying to mould surface detail. You can add that later.

Vac-Forming

For my ambitious Sopwith Dolphin project, there was no avoiding the fact that I had to make some vac-formed bits. I had never tried vac-forming before, but it turned out to be quite easy. All you need is the ability to make a box, and recourse to a vacuum cleaner. And a grill.

Vac-forming box

Stretched Sprue

So, stretched sprue.

One way that you might use stretched sprue: from an abortive SE5A project.

Actually, there's probably not much new to say about stretched sprue, but this is how I do it:

Sopwith Dolphin Retrospective No. 2 - Fuselage Framework

Here are some photos of the first stages of the project. The photo below shows the first cutting of plastic.

First cutting of plastic

Sopwith Dolphin Retrospective No. 1 - The Theory

In my initial posts, I promised more details about my overambitious project to build a Sopwith Dolphin in 1/72nd scale,and now at last here is a post that looks like bearing out that promise, by means of a superb video followed by some no-more-than-adequate explication.

If you're going to scratch-build a fighter plane at all, then a First World War fighter plane is your only man. I think Flann O'Brien once said something of the sort. But what Flann O'Brien didn't make clear is that this is because there are a lot of flat and simple curved surfaces on a typical First World War aircraft, which you can reproduce by the good old method of cutting up bits of plastic and gluing them together. However, it was obvious right from the start that some vac-forming was going to be necessary for the decking and cowling, and so I had to tackle the problem of making sure that the built-up bits matched up with the vac-form bits. Another problem I made up for myself was how to improve on the methods I had used in the past to represent the internal girder structure. What I had done before, and what a modern kit usually does at this scale, is to represent the longerons etc. on the inside of the fuselage. The disadvantage of this is that it's very difficult to paint neatly. Also, it's quite difficult to make all the bits line up properly.

The solution I came up with was as follows:

1. Build up the framework as a freestanding structure, using a lot of Evergreen strip.
2. Build the lower fuselage separately from 0.4mm sheet, standing in for canvas, plywood and aluminium.
3. Carve wooden moulds for the vac-formed bits, sanding them down until they just fit into the fuselage skin.
4. Do the vac-forming
5. Cut the vac-formed bits to size
6. Put everything together

One nice feature of this technique is that it mirrors the construction of the real thing, to some extent, in that the structural bits in real life are structural in the model. And it means that the fuselage skin can be not too far off scale thickness.

That's the theory. How did it work in practice? Pretty well I think, as you will see in subsequent posts.

21/11/10
Post retooled in order to increase fidelity, with recessed panel lines and addition of the word "fighter" before "plane" in Flann O'Brien quote. This makes it sound a bit more like the original, you see.

Current Project

Here are a couple of pictures of my current project: a scratch-built Sopwith Dolphin in 1/72nd scale. More posts soon:

The fuselage box structure

View of engine before forward decking goes on

Fuselage almost complete