>Do oil fired locos have a blast. Do they need to draw the fire.
Yes. The air requirements for a particular rate of energy consumption
are practically the same, no matter what the fuel, so long as it is
carbon-based and produces carbon dioxide and steam as the combustion
products. To achieve the high combustion rates in a steam loco, the
air has to be forced. The forcing of air in a coal-powered loco was
not primarily to force it through the fuel bed against the bed's
inherent resistance (which was fairly low), but simply to provide the
massive amounts needed to support the high specific combustion rate,
which was many times that usually achieved in (e.g.) a static power
plant like that of a power station.
>It seems to
>me that a steam loco without a hearty blast and lots of smoke would not be
>much fun to see work ing hard.
>Bob.
A number of condensing locomotives were built at various times,
principally South Africa and Russia. Their blast was usually provided
by an air turbine. It whined. For some reason, it always sucked,
rather than blowing, probably because of difficulties in hermetically
sealing the grate/ashpan area. "They say" these locos were audibly
unattractive, but I imagine not to a plane enthusiast!
Smoke of course, has little to do with the air method, mainly the
adequacy of the amount supplied. There shouldn't be any at all, of
course, if the fuel is being burned efficiently. Although the
potential for burning liquid fuels at 100% efficiency would seem to be
higher than the potential for coal, oil-fuelled locos were often
smokier than coal-fired ones- you could nearly always tell from a
distance whether it was an oil-fired or coal-fired VR J class that was
chuffing up the track towards you.
Geoff Lambert