Keep trying, and failing, to start engine - what am I doing wrong?

[Noah Buttes]

Hellburns work by forming a recursive feedback loop between the gasses in the burn chamber and the gasses in the heat exchanger pipes.

In other words, the pipes transfer more heat into the air than they actually lose. Then the excess heat in the air is transferred back into the pipes, which radiate additional heat, and so on.

Basically, it's a perpetual motion machine of the first order.