Well, time to report back. Yesterday I smoked a chicken in the "earth smoker" as I call it. First I brined the chicken in salt and OJ. Then I rubbed it down with mustard, basil, pepper and a few secret ingredients. I started by putting a good bit of charcoal in the right hand hole. I gave the charcoal plenty of time to get grey ash on the visible pieces...then put the brick over the top. No significant increase of temperature was evident in the center chamber. Lack of Oxygen snuffed it out, despite my air intake pipe.
So, I began a fire in the left side hole. This was more effective in creating an increase in temperature in the center chamber. So, I took the charcoal out of the right side hole, and put it into the other side. With lots of fuss and extra wood, I was able to get the center chamber temp up to 300. It took a long time before I was able to hold it at 250, and could only do so if I kept a lit flame. After an hour of warm up, it seemed to stabilize, and I didn't need to watch it constantly to maintain temp. Lots of stick burning, as charcoal alone didn't seem to get the temp high enough. Smoke was mostly white with occasional black, and seldom blue.
I put the chicken on for three an a half hours, and my grill thermometer stayed between 220 and 260 pretty steady. I turned the chicken twice...finally I removed it to see this:
It was a little crispy, on one side, with an inedible wing and leg...but the remainder was fully cooked, and FANTASTIC...flavor just exploded on the tongue. I'm quite tickled.
Despite this success, I am going to slightly redesign the 'earth smoker.' I am filling the right hand hole entirely, as it was impossible to keep a fire going in it. The left hole is going to be moved closer to the main chamber, and I believe this will decrease the warm up time and, hopefully, allow a charcoal only run.