When the idea of an engine hacks theme was being kicked ... We’ve never seen a liquid-fuel rocket build before, so that’s what this roundup evolved into. First up is [Robert Watzlavick ...

The trick is to turn the fuel on, remove the air source ... Needless to say – don’t try this particular engine build at home.

Ilmor says the next step is to build another working prototype with targets of 10% better fuel efficiency and 20% less engine weight compared to an equivalent four-stroke engine.