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Post by cplmickey on Jul 19, 2011 22:03:28 GMT
I wondered if anyone has done any mods to the standard blast pipe. My Simplex steams ok but I've found it runs better with the blower just cracked open. This seems to suggest that the blast pipe nozzle is too big and so the exhaust doesn't draw the fire enough.
I'm thinking of making a simple top-hat bush to reduce the diameter but wondered how far to go. Does anyone have any thoughts on this please.
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Post by drjohn on Jul 21, 2011 4:17:33 GMT
Hi Mickey
I have built a couple of Simplexs and used the standard Martin Evans spec for the blast nozzle.
There are two factors here in my opinion - one, if the track you run on is pretty level, the loco will not be working hard and may need a little blower, and the other one is the coal you are using. I have tried a variety of fuels, but always end up with anthracite beans (the sort they use for hopper fed burners, about 3/4 to 1" ) and it works extremely well. My track has a long slow incline followed by a fierce 1 in 20 climb where I've put sand filled epoxy on the rails to get traction, but I can start the slow climb with 30PSI on the clock and by the top, the safeties are blowing, but conversely on the level or slightly downhill gradient, if I don't keep a bit of blower on, the pressure just drops off.
Anyway, it gives you something to do and makes you feel as if you are in control!! ;D ;D ;D
DJ
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Post by cplmickey on Jul 21, 2011 11:38:44 GMT
Interesting. The track is flatish out of the station so the loco doesn't work hard to start with, however there is then a long incline when the regulator is well open. Perhaps the fire loses something in the early stage without the blower, I'll have to experiment a bit.
I'm still trying different coals. I've tried steam coal (the polish stuff tho I believe) and the club coal which is off the shelf anthracite. I'm not sure I'm experienced enough to comment on the merits of either but I wonder if the steam coal is too big - I'm breaking down lumps intended for full size locos.
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smallbrother
Elder Statesman
Errors aplenty, progress slow, but progress nonetheless!
Posts: 2,269
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Post by smallbrother on Jul 21, 2011 11:52:41 GMT
The best coal is anthracite beans from South Wales. Nothing else has the calorific value or low ash content. I have run small 5" locos for 4 hours or so without even having to rake the firebars. The fire would have gone on longer I am sure but my backside just couldn't take any more of the hard seat.
It is 20 years since I worked in the coal mining industry but the geologists I worked with all reckoned there was nothing on the planet to compare with the S Wales anthracite. These guys would know as they had worked all over the globe.
Other fuels will work but not as well.
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