There’s a bunch of videos on the tube of these small scale engines. I can’t imagine the time and money it takes to build these, but they are freaking cool as hell.
used to deal with tank engines back in the late 70s.1790 cubic inches,fuel injected and twin turbos.the recruiters knew a gearhead when they saw one.back then all that was unimagineable.the tank recovery vehicle ran on gas,not diesel,and would shoot 2 foot flames out of the exhausts when you opened the throttle.nice on cold days.