Been playing around with stove design lately.
A low-pressure sideburner with no preheater (eg. a Supercat Stove) takes so long to warm up that it boils a half-pint in 7:30. By the end, it is roaring.
Adding a pre-heater, ie. a ring of fire around the outside of the stove which burns for the first minute or so, cuts the time to 4:00.
This reminds me of a little experiment I tried last year, using a much hotter and longer pre-heater. I positioned two aluminium foil cake cups, one above the other, below a pot, so that the flame from the lower cup would act directly on the base of the upper cup. I set light to them both, and the lower one made the upper one boil and sizzle so fast that it burnt out in under 2 minutes.
But it wasn't a very controlled experiment, and quite inefficient. The flames leapt up around the pot, and much of the heat was lost to the air above it.
I wonder if this principle could be applied in a controlled way, to cut boil times to 2 minutes. Has anyone tried it?