Pudding Wrestler's Perfidious Projects: Easter Holidays update two

Here we are on the morning of the fourth day of the project and progress has been sadly slow. I felt pretty rotten yesterday afternoon and went to bed early. I'm feeling a bit better today, so I hope to get more work in. Although I am also planning to drive over to Wonthaggi (the nearest large town) to shop for some supplies and sundries. For some reason, I can't find bath toys at all where I live. This has nothing to do with the project, it's just been annoying me.
Anyway - photos.

The basic shapes and details of the engine section are now complete. I still need to add rivets and a lot of details like pipes and runes and smaller parts.

The big stack is actually the second attempt - the drill wrecked the first attempt so I had to get creative. I drilled the three holes three times with different sized drills and with a second tube nested inside to stop the bits tearing things apart. This worked fairly well, but not perfectly.

I have not really integrated the front edge of the engine into the upper bodywork yet. There are still some gaps which need filling.

And once more, the glorious yoghurt tube topper comes to the fore! The PVC pipe connectors along the top turned out to be an unusual size which I could not find any pipe to match meaning it was a problem to get them nice and solidly joined back to back. Then I found a cardboard receipt paper roll which was exactly the right size... To be honest, a lot of time yesterday was spent scrounging round for the right parts.

As usual, feel free to speculate on exactly what this is in the comments. I feel it should be becoming clearer, but then I know what it is so I have an advantage...