NickB
Western Thunderer
When the LNWR decided it needed an eight coupled engine for its heavy coal traffic, before committing to large-scale manufacture, Webb built two prototypes. No. 2524 was simple expansion, and no. 50 was compound. The compound was decided on and no. 50 was followed by the A class, but there was no suggestion that No. 2524 was a failure because it, along with the rest of the class, served for many years and they all, simple and compound, eventually morphed into the simple “Super D”.
So why model a prototype? It was the tender wot dun it. I had most of the parts for a Webb tender (left over from the Precedent described elsewhere on this board), but only the earliest 0-8-0s ran with them. After the excitement of building a loco, I find the tender is, well, a bit humdrum, so there was every incentive to make maximum use of existing parts. So it had to be a loco that hauled a Webb tender.
And why no. 2524? Because I preferred its looks. The compounds (no. 50 and the A class) had outside cylinders which were steeply inclined, and that and the short conn rods gave them almost a toy-like look. I know there are a number of models of the A class in various scales, so I don’t suppose everyone shares that view.
Anyway, the choice was made. I like the clean, purposeful looks of the simple engine, and inside Joy valve gear would be an interesting challenge. Over the years I’ve done most of the major valve gears but Joy gear is missing from my portfolio.
I started the project by creating a CAD model of the chassis parts. It’s not a complete model down to the last nut and bolt, and where there are identical or mirror image copies of the same component I don’t put them all in. It is easy to do in Fusion, but on the screen it just adds to the clutter. I only do enough to help me decide how it should be assembled, check on fits and clearances, and provide me with the data for some of the manufacturing methods.
As with the previous loco, I intend to try out some of the new manufacturing methods that are now available, but we will come to that later. Enough waffle, it’s time to start cutting metal.
If you're sufficiently interested, here is a lo-res animation of the Joy valve gear. I didn't need it, but with Fusion I can do it, and creating it occupied a cold and miserable day last winter when the workshop wasn't in the least bit attractive.
Nick
So why model a prototype? It was the tender wot dun it. I had most of the parts for a Webb tender (left over from the Precedent described elsewhere on this board), but only the earliest 0-8-0s ran with them. After the excitement of building a loco, I find the tender is, well, a bit humdrum, so there was every incentive to make maximum use of existing parts. So it had to be a loco that hauled a Webb tender.
And why no. 2524? Because I preferred its looks. The compounds (no. 50 and the A class) had outside cylinders which were steeply inclined, and that and the short conn rods gave them almost a toy-like look. I know there are a number of models of the A class in various scales, so I don’t suppose everyone shares that view.
Anyway, the choice was made. I like the clean, purposeful looks of the simple engine, and inside Joy valve gear would be an interesting challenge. Over the years I’ve done most of the major valve gears but Joy gear is missing from my portfolio.
I started the project by creating a CAD model of the chassis parts. It’s not a complete model down to the last nut and bolt, and where there are identical or mirror image copies of the same component I don’t put them all in. It is easy to do in Fusion, but on the screen it just adds to the clutter. I only do enough to help me decide how it should be assembled, check on fits and clearances, and provide me with the data for some of the manufacturing methods.
As with the previous loco, I intend to try out some of the new manufacturing methods that are now available, but we will come to that later. Enough waffle, it’s time to start cutting metal.
If you're sufficiently interested, here is a lo-res animation of the Joy valve gear. I didn't need it, but with Fusion I can do it, and creating it occupied a cold and miserable day last winter when the workshop wasn't in the least bit attractive.
Nick
