This forum saved my butt(and many future butts)

[pete10]

While working on my reverse flow offset build, I started pouring through the info linked in the KCQers ROADMAP to the QTALK forum post. I stumbled across the Firebox Calculator

After punching a few numbers, I had a "how many bowls of my usual cereal do I have to eat" moment. My original design had two 3" pipes delivering the heat and smoke to the far side of the cook chamber. The calculator spit out 9 as the number of penetrations of that diameter I would need. NINE! It's funny, I joked about calculating Reynold's numbers and pipe velocities with my work buddies not thinking I would under design the duct!

Back to the drawing board, and I am taking back pipe and blast gates! I am going to go with one 3"X15" rectangular penetration. It will be fabbed from 1/4" steel and be flanged with angle as it meets the firebox and cook chamber. I figure it will have to be around 2.5" long or so to clear the drum base features. I'll continue it inside the cook chamber as an open topped duct. I'll fab four plates to sit atop the duct with the ability to create slots at any place along the duct length by sliding the plates apart wherever I want to tune the smoke/heat.

THANKS to the board for having so much good info!

 

[NorthwestBBQ]

You're welcome!

 

[Ron_L]

I don't know if this helps, but this is the view into the firebox of a Lang model 60 reverse flow. You can see the opening from the firebox to the main chamber.

 

[pete10]

I don't know if this helps, but this is the view into the firebox of a Lang model 60 reverse flow. You can see the opening from the firebox to the main chamber.

Ron, that certainly helps. Mine will have a short transition piece between the two chambers. I am going to minimize it as much as posslble.