Jock Gill, Vermont, 2011
Jock's new TLUD Design. It has a passing similarity to Lanny Henson's Sidewinder, but instead of 4 symettrical slits, to provide the 'vortex' at the heart of the cooker. The iCan D uses only three secondary air apertures for maximum turbulence and asymmetry. It also uses a more triangular cut arranged such that the resulting tab is at 45 degrees and can, when folded into the can, act as both a vortex generator and a concentrator.
Currently I have only tested the mid-sized coffee can unit with 142 grams of fuel. This gives me a runtime of about 27 minutes -- start to flame out. It has yielded 21.8%% biochar as a percent of weight of fuel -- soft wood pellets.
It gets good results when loaded with 25% of the capacity of the can - in this case about 142 grams of wood pellets. Run time: 27 minutes. Smoke gone in well under two minutes. Biochar was very clean, 100% charred fuel with no floaters in a water quench. Minimal ash. Biochar harvest was 21.8% of the weight of the starting fuel load. Only minimal soot in the stack gases for about 3 minutes at the peak period.