[Stoves] Extended burn time in TLUD Chinese camp stoves

[neiltm at uwclub.net]

I came across this youtube video by someone claiming a one hour burn time 
with wood in the Chinese wood gas camp stoves:

https://www.youtube.com/watch?v=RdcVqrDMPag

Previous experiments stacking twigs or lengths of wood vertically 
typically made no difference over chunking, snapping and just chucking 
stuff in and shaking it down, but I thought I would try to reproduce what 
was done in the video.

I had some hazel coppice stems which I cut to length and split into 
quarters.  This morning, once thoroughly dried out on top of our gas 
boiler I stacked the chamber much tighter than shown and was immediately 
impressed by how much heavier the stove was over a normal loading.  
Quarter sections like that allow for very efficient loading with minimum 
gaps, but still plenty of room for sufficient primary air.

The 'control' was knowing that the same hazel chunked and zero moisture 
would be a flare up lasting about ten minutes.  What I got was a good 
steady but robust and smokeless flame for between 25 and 30 minutes, and 
no need to refuel as I usually do to complete a breakfast cook.  There 
was some very nice char left over as well.  This is the longest cooking 
time without refuelling I have achieved with this stove, doubling or 
trebling the burn time, but still with a strong fire.  Definitely scope 
there for an air dried moisture content to prolong the burn still further 
at a still usable heat output, and presumably what the author of the 
video did, though she doesn't say.

More fuel preperation involved, but not hard to imagine sustainably 
growing and coppicing wood like hazel, chopping it green in a suitable 
guillotine with a measured stop, and possibly even a simple held blade 
for more even splitting with a hammer.  I seem to recall one of Dr 
Nurhudu's videos showing similar neat vertical stacking of split wood in 
the wood version of the Prime stove, so can definitely appreciate the 
advantages now of vertical stacking, but it must be tight packed split 
wood to confer the extended duration advantage.

Neil Taylor (emerging into a mostly very wet English spring)