Re: Alisan plume?

[Landon Solomon]

It has been my understanding (through various online conversations) that no 
plume means that the heat of the exhaust draught is keeping the steam too 
hot to show a plume (until it's spread wide enough that you can't see it 
anymore.)  This means that less energy is getting into the boiler than is 
possible due to a less than perfectly efficient boiler.  Basically, the 
other locos are more efficient than the shay, or you're running the fire 
too hot.  :)  Note that you shouldn't have to keep the safeties popping to 
run her well, doing so is a waste of fuel and water...

Or at least that's what I remember being told.  ;]

Trot, the fox who's no design engineer, but is an equipment tech...

At 07:38 PM 2/25/03, Gary wrote:
OK, another naieve question.

The Steamlines Shay, Ted's Roundhouse 7/8th scale Porter, and the Frank S
all have obvious plumes from the smokestack during cold weather. This Alisan
Shay runs almost plume free. The pop offs offer evidence that steam is
powering the critter, but only episodic plumes occur from the smoke stack
and those usually when the engine starts from a stop.  Any hypothesis occur
to any of you, let me know.  Is it a real efficient engine? Does the exhaust
cool too much to cause a plume or could the exhaust be too hot and the steam
dry?
Curious in Oregon

Gary - Photos of Alisan shay look like the loco is cold except for the pop
offs.


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