[Stoves] Rocket+Woodgas (Hybrid) Stove (Prototype)

[Crispin Pemberton-Pigott]

Dear Dr R

The lower section of this interesting layout is the same as the stoves David
Hancock was working on in the early 80's, a time when it was thought that
the fuel could feed itself downwards.  The problem was that the fire would
work its way back into the fuel magazine.

This combination with a restricted air supply and admitting secondary air
seems to have potential.  You will notice that the flame is much shorted,
and probably much hotter.

I foresee the problem (in general) of the ceramic bricks breaking because
they are heated very differently on oppostite sides, but that is something
that can be addressed separately.


It looks as if the flame is small / short enough to be able top put the pot
on top.  Of course I like the fact that it is a batch loader so it can
operate unattended for some time.

To me it is on the right track.  Concrete on the outside where temperatures
are low, ceramic where they are high, choked primary air supply to a reserve
of fuel, preheated (by the bricks) secondary air below the pot.

My suggestion for a dimensional change is to elevate the pot to about 125mm
above the secondary air inlet to let the flames finish before hitting the
pot.

If you were able (i.e. custom made bricks) angle the secondary air to spin
the upper fire.  This will raise the flame in height (a bit) but give very
good mixing.  You could also [probably reduce the height of the secondary
air holes by half just to see if it made the secondary air reach all the way
to the center.

I suspect it will burn dung very cleanly.

Best regards
Crispin