I constructed the chassis for my Aeolus model from several separately printed components:

 

• Outside frames, with rivet detail
• Inside frames, with splasher tops
• Front Buffer beam, linking frames
• Rear drag-bar and footplate, linking frames

 

After printing these parts, I fused them together by welding the seams using a fine-tip soldering iron set to 200°C. This proved easier than I expected, partly because the PLA plastic has low thermal conductivity, so it was possibly to align and hold the parts in place by hand. After softening the plastic, it does not ‘set’ instantly so it is necessary to continue holding the parts together for a few seconds after making each joint. The result of this process when applied to the inside frames is shown below:

 

Frames fused together by means of a soldering iron tip.

 

I created 3D-printed wheels of both 6’ and 3’ (prototype) diameters, using the method I have described in previous posts. Unusually, I couldn’t see a reference to the numbers of spokes on the sketches by E.T.Lane, so made my own judgement – rather more spokes than shown on the Bird drawing, which wasn’t created until the early 20th century.

 

I then added the outside frames, again using a soldering iron to attach them at the ends but leaving some flexibility in the centre, so that they could be pulled out a little, to allow the ends of the driving axle to be passed through since, unusually, the axle is positioned above these frames.

 

The engine was now rapidly reaching completion. As an experiment, I thought I might try using 3D-printing for the guard-rail ‘fences’ on each side of the footplate. I reasoned that these were not so different from the slatted windows I had already created successfully for BG cattle wagons.  In fact, they did print accurately and cleanly and, although they could easily be damaged by rough handling, they were sufficiently robust for a display model.

 

3D-printed guard rails on printer bed

 

I provided ‘feet’ below the end pillars that could be firmly attached to the footplate by using a touch of the soldering iron tip. The appearance of the model was now as shown below:

 

Rear three-quarter view of my Aeolus model

 

 

Air Resistance Experiments

 

In my previous post, I mentioned a pillar or stanchion at the front of the engine, shown on the Lane sketches with no indication of its purpose. I speculated that there might have been a curved rail around the front of the engine.  Since writing that, I have come across the following passage in MacDermot’s ‘History of the GWR’, Vol. One. There is a lengthy chapter about the design and performance of the early broad-gauge locomotives. Concerning the engines supplied by Tayleur, of which Aeolus was one, it records that: “Another interesting suggestion is contained in one of Brunel's letters to Tayleur & Co: 'A bow or round front to take off the direct action of the air against the flat surface of the smokebox.’ Nothing appears in the correspondence or other papers to show whether this was actually fitted to any engines, though it seems likely to have been tried.”

 

Did the stanchion on top of the mounting for the weigh-bar support a curved bar across the font of the engine to carry such a bow front? Was the unusual position of the valve gear also in some way connected with such experiments? With those thoughts in mind, the front of Aeolus could possibly have looked like this at some period:

 

Stanchion and curved rail supporting bow-front

 

… or even, like this (shades of LMS 'Coronation'):

 

My model Aeolus with Bow Front

 

Before this thread merges into ‘Imaginary Locomotives’, I’d better take my model to the paint shop. I shall add the control rods and levers, of which there are several, after painting the main structures.

 

 

Controls and actuating rods on Aeolus (drawings by E.T. Lane) - revised

 

Adding a Tender

 

Unlike her sister engine ‘Vulcan’, which was converted into a tank engine, ‘Aeolus’ was re-built as a tender engine and we are very fortunate that young Lane also made sketches of this tender, as shown below:

 

Aeolus Tender, sketched by E.T. Lane.

 

Like many of Lane’s other sketches, these included his inimitable addition of details; in this case, these appear to be mainly of brake gear not included on the main sketch.

 

The main sketch shows the interesting feature that the sides of the tender extend outside the wheels and there are ‘cut-outs’ to provide access to the springs, presumably for lubrication purposes. This aspect of the design led me to adopt a slightly different method of construction from previous tenders that I have built.

 

I started by drawing the outer sides of the tender, using the sketches and dimensions provided by Lane. The sides have a ‘flare’ at the top and oval cut-outs over the springs, for which the dimensions were helpfully shown by Lane in one of his sub-sketches. I then drew the back of the tender, with curved ends and flare to meet the profile of the sides.  Next, (1) I created a simple flat floor, with cut-outs for the wheels, to hold the sides at the appropriate distance apart for a broad-gauge tender. (2) Using the surface of the floor as a template, I sketched the outlines for an inner frame that (3) I extruded upwards to support the top plate of the tender. I also drew the outlines of the springs on the outer faces of the inner frame and extruded these to form the springs, visible through the openings in the body sides. (4) Finally, I added the top plate of the tender. I illustrate these steps below:

 

Stages in constructing my Model Tender

 

I had broken the tender model into parts such that each had a flat side to lie on the printer bed. After printing these parts appeared as shown below:

 

Printer Tender Components on 3D-printer bed

 

Final assembly of the tender was simply a matter of running a soldering iron, set to 200°C, along the seams, to fuse the various parts together.

 

 

My 3D-printed Tender model

 

So now the tender can join its partner engine in the paint shop…..

 

Mike