Hopefully I can spread a little light on the subject.
I actually designed a burner for the C18 and made a prototype using the two jet principal which works for me. Channing sent my drawings to China and they tried to replicate it but when their prototype arrived, it was not workable so they decided to go with their original design. I was sad that they weren't able to use my design and was hopeful that theirs would work.
First lets talk about ceramic material. There are two types of material I have used. The first one is shown above and in the Bic burners . It is hard and has small ridges and holes. It burns fine but it also gets very hot throughout the plate and will cause a combustion under the plate which will ruin the burner. The second material is softer with pronounced pyramids and larger holes, This material is bullet proof and will handle any temperature. I was getting it from Bruce Engineering in the UK but they are no longer carrying it.
Now to the design.
Accucraft is using a drafted design in the C18 which id not very efficient for ceramic burners. It draws air around the burner then through the tubes and out the stack. This design is great for coal and alcohol where the air is used for combustion but where a ceramic burner gets all of its combustion air from the holes in the jet holder, the additional air drawn in just cools things down.
To have a proper drafted system, the smokebox must be sealed and the firebox needs to have air passages around the burner box. This limits the size of the burner box.
My design uses a sealed firebox where the burner fills the entire bottom of the firebox and is sealed around the edges. The smokebox is vented at the bottom similar to poker burner engines. My larger engines have had burners as large as 15 square inches. Needles to say they produce more steam than would ever be necessary.
As for your tests, the blue flame tells me that the oxygen level is low, This could be caused by the tube length to diameter is off. the length to id should be 6:1 to get the proper venturi effect. A red glow means too low a fuel to plate area and a bright yellow glow is perfect,
Here are photos od the good ceramic and a strong operating burner.
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