Sopwith Dolphin - Undercarriage

Right, I've just finished the bits for the undercarriage, and this is what they look like.

These pieces were going to be made from a mixture of plastic strip and aerofoil struts, and I decided that they were going to need some precise cutting to fit together properly; in fact, they were going to require a degree of precision that I had not hitherto come close to achieving. So I went to Frome Model Centre (one of the best model shops in the country, in my opinion) and the very helpful lady there sold me a kind of miniature guillotine made by a company called Amati. It was exactly the type of small bench tool that I imagined might be easily available from shops; and to be honest I should have got one a long time ago.

Anyway, now I've got it, it works a treat, but at first I was slightly disappointed because if you try to cut thin plastic strip, the blade pushes it out of alignment and you don't get the accurate cut you want. If you were doing this sort of thing for some joinery project, you would clamp the pieces of wood; but with pieces of plastic measuring 0.75mm that's not really feasible. I soon found out that the easiest solution is to tape the pieces down. Then it's a piece of cake (though this tool is probably not suitable for equitable division of actual cake. Oh, go on then, maybe it could manage half a Jaffa cake).

In the shadow of the guillotine

So I made a start with the spreader bar. I was going to make this from an aerofoil strut; but it has to incorporate trenches for the split axle and there was no chance I was going to be able to cut these out accurately. So instead, I built it up from plastic strip and then sanded it to an aerofoil shape. I made it slightly long, because when sanding a long linear piece, it's easy to round off the ends a bit. Then, when the section was right, I cut the whole thing to length with my new guillotine.

For the undercarriage legs, I drew up a cutting guide in TurboCAD, and added aligment lines corresponding to the fence of the guillotine. The technique was to print out the guide, cut it along the fence alignment line, tape the pieces to the guide and tape the guide to the guillotine.

The first stage was to cut mitres in the aerofoil struts and join them together, with results like this:

The next stage was to tape the pieces to the cutting guide again and trim them to size:

After this, I had to cut the slots for the split axles. I did this by drilling a pilot hole and then opening up with a knife. A rather fiddly job, this, and I had to start again from scratch with one of the pieces.

Finally I added details from 0.3mm plastic rod and that was the undercarriage done.

I've just remembered that I was going to add locating pins. But apart from that  the undercarriage is done.