What is the cause of turbojets'/gas turbines' high power to weight ratio compared to piston engines? They certainly use a generally less efficient thermodynamic cycle.
2$\begingroup$ The amount of air/fuel they burn per second... Some jets using full afterburn can empty the fuel reserves in 10 minutes or so... can't do that on a car $\endgroup$– Solar MikeApr 2, 2020 at 16:23
2$\begingroup$ To put a number of Solar Mike's comment, the air flow through a large turbofan a takeoff is more than 1 tonne per second. Try getting that through an IC engine, even with a turbocharger. $\endgroup$– alephzeroApr 2, 2020 at 19:13
Turbojets and turbofans support extremely large mass flow rates of air & fuel through them, relative to their weight. (The majority of the work performed by burning that fuel is taken up by running the compressor stage of the engine and what's left over generates thrust.) In comparison, piston engines cannot support similar fuel burn rates relative to their weight.