tiny rocket mass heater hat

Mud and I came up with this idea a little over a year ago and we are starting to implement it here at wheaton labs.  

Here is an early attempt at the amazing dogstar (photo thanks to stephen):



This is a cottage rocket.  Reports are that you go to bed at 75 and wake up at 55.  That's too cold.  We need to add a mass.

Here are some changes that mud and i are requesting:


opening:
    wider (at least 15 inches wide)
    lower (maybe no more than 5.5 inches from the barrel)
          - this will make the overall thickness of the mass a bit thicker

inside:  want two bits of angle iron riding above the top of the barrel

overall cob mass:
   overall height is perfect
   shape of the top is perfect
   would like the mass to be 3 inches thicker all around
   would like the mass to ride down the side of the barrel 3 inches
   (optional) have the mass cover the back of the barrel
       - a sorta poor man's heat shield plus more mass

That is a nice bit of cob!
Low and wide sounds a lot like the opening to a pizza oven is that what you're aiming at?
It looks a little like some of Matt's earliest work where he was cooking directly over the top of the barrel.

pizza ...   cookies .... pie ...


Mostly, wanna not touch the middle of the barrel - that could lead to spalling.  And instead of sending radiant heat to the ceiling, let's heat a mass and keep the heat a little lower.

I REALLY like the idea of the cob hat, tho I would want an opening big enough so I could still use the top of the bell/barrel to cook or heat water. So a hole large enough to insert a small to medium sauce pot. Does that seem, physics-wise, possible?

Yes, that is a possible path.  

I am looking into making the opening shorter and wider - to better facilitate pizza.