15522Re: [ausnarrowgauge] RE: Australianise an On30 Porter
- Sep 20, 2013This is not correct - many 'Welsh' NG locos have sloping cylinders - albeit not as extreme as the Porter example. Because small NG locos have small diameter wheels it is necessary to have the cylinder bore centre line above the wheel centre for clearance. As a result, to achieve the desirable drive geometry noted, the cylinders slope backward a few degrees. This applies to almost all the Hunslet quarry locos - particularly the 'large' designs such as Linda, Blanche etc. Many other makers of small NG locos, W G Bagnall, all have cylinders set at a slight angle.Once you get a wheel over two foot in diameter it is easier to arrange a cylinder bore on the driving wheel centerline - witness Dolgoch, Talyllyn, the W&L tanks. Even so, the Corris Falcon design, with 30in driving wheels still has sloping cylinders - as do many others.
I agree with you Ian. I think there might be a few welsh locos with sloping cylinders but they are pretty uncommon. The vast majority of manufacturers built locos with horizontal cylinders on the level of the axle centres because that is the most energy efficient geometry.
I'm not really sure why the Porter company put them at an angle.
--- In email@example.com, <ianajng@...> wrote:
Hi Rod & others,
I think one of the significant changes that Roger Hill made to his Porter conversion, with, in my opinion, a very signficant improvement in the visual appearance, was to change the cylinders from the angle they are on the ex factory Bachmann models, to being virtually horizontal. I'm sure someone will prove me wrong, but off the top of my head I can't think of any timber tramway loco that ran in Australia that had cylinders at an angle even close to those the Porter comes fitted with. Dropping these down, and replacing/modifying the valve chests which would then be incorrect, would contribute substantially to a more realistic appearance.
As regards Hornby "Bill & Ben" etc style chassis, I understand from UK based NG forums that the chassis made in China are much better runners at slow speed than those made in the UK. Some also apparently have a metal footplate, others plastic, so it presumably is worthwhile looking around.
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