Fire to crown sheet distance

[cp4449]

Multiple hole style

[JohnHudak]

So should the front row of burners point slightly back? I'm using 6 marty burners, three rows of 2.. I can angle the front row back towards the firedoor, so that they aren't pointing right at the angle on the SS arch.. Or am I overthinking this?
Thanks...

[NP317]

That sounds like a positive idea.
RussN

[ChuckHackett-844]

No disagreement with what you say (been there done that with GE / WESTINGHOUSE, and yes even Zink), but flame on our boilers doesn't realistically hurt...cannot say that I have ever seen a steel (or copper) model boiler that failed as a result of this type of impingement...and cannot say the delam would even be a consideration here.
....
Actively TRYING to keep the flame away from a firebox this size of boiler is a bit like tilting at windmills since the variations in operation will gobble up any dream of clearance control unless you are running the multi-slot / hole furnace type of burner.

The issue in our boilers with propane is that as soon as the flame contacts the water legs or the flues (hence the need for an arch) the flame is quenched below its burning point and does no more heating.

This is also one of the causes of the 'acid' smell coming from some propane engines (unburned hydrocarbons).

One can arrange special burner layout to keep the flame from hitting the water legs ('tube' type burner) but one could also place a stainless steel strip about 1/4" from the water leg and let it glow red hot. The strip will be heated to red hot (thus not quenching the flame) and radiate the heat to the water legs.

Again, an arch prevents the flame from entering the flues too early.

Oh, yes, and the bottom of the flame should be level with the top of the mud ring.

[Harlock]

For Marty Burners / Locoparts / Solarflo burners, they need as much head room as you can give them, put the manifold down at the mug ring. The commercial burners are designed for 18" of headroom for complete combustion, but they obviously do work in our locomotives regardless.

Slot and hole burners are much less tall in the firebox so they automatically get an advantage. They should be fairly low in the box as well, however. There is more room to add an arch plate with those as well.

In regards to baffles and closing up the fire pan - it's different for every locomotive. I found that with the Chloe in order to avoid the flame sucking out, I had to leave the bottom completely open, or face the prospect of killing the draft by adjusting the petticoat or blast pipe height to make it intentionally wrong. Then the engine doesn't sound as good. It steams just fine. My general suspicion is that the small diameter, short boiler has much sharper exhaust drafting qualities than a larger, longer boiler which tends to dampen the effect a little. The Chloe draws quite a vacuum if you try to close up the box even a little bit. I wasn't willing to compromise on messing up the front end to do that.

Try a baffle plate and see what happens. if it doesn't work you can always take it out or start drilling more holes in it. This is one of those '10 live steamers, 10 different opinions' things...

Best,

-Mike