difference batchbox vs shorty bells

dear permies, after having already built a bell for a batchbox I am preparing to build my first bell for a shorty core.
in the batch box bell the statigraphy was to build a double wall in the upper part, from just below the riser outlet up. in the shorty bells that I have seen here on the forum it does not seem to me that this is done. but a double wall is built only on the opposite side to the gas outlet, am I right?

Hi Cedric;
Change the 'double wall' to 'firebricks', and yes, you are correct.
Shorty seems to keep her high heat down low in the bell, unlike the traditional batchbox that shoots it directly toward the top.

Double-wall bells are primarily constructed with regular bricks, except for the inner skin above the riser.
My single-wall brick bell with a Shorty inside has a row of full-size firebricks sitting on top of the core that deflect the heat from the clay brick front wall.
I also use split firebricks as a roof over the core.
Temperatures are much more reasonable using the Shorty design.
The same strong double ram's horn flames as the regular batch, but they slow significantly in the upper portion of the riser.
You will be impressed; Peter has created a new masterpiece.