Yeah, some designs deal with pre-heating the air in a double wall design, kinda sorta like he was doing. But, others simply allow more air into the mix in a directed manner. The first one I played with sound like a jet engine when I was burning cardboard, according to my daughter, but ashes clogged it up easily when I burned limbs. I've since modified it.Basically the smokeless fire pits-burn barrels let in more air. I have a stone fire pit that is 4 layers high. The middle 2 layers have about. A 1.5 inch gap between each stone. The gaps make a huge difference.
In the video, he could have just drilled.some holes in the barrel and been done with it.
Buy it off the shelf, when I can spend more money, time, effort and frustration to create a less efficient and crappy looking product?Just buy the solo stove bonfire or Yukon.