> The real efficiencies come when you use like an expander cycle or a staged combustion cycle or you feed the gas generator exhaust back into the nozzle like Me

> The real efficiencies come when you use like an expander cycle or a staged combustion cycle or you feed the gas generator exhaust back into the nozzle like Merlin Vacuum or F-1. If I remember correctly, with F-1 the gas generator exhaust was sent to the nozzle to cool the nozzle, not to add efficiency to the engine main cycle. We're still trying to get more efficiency from isochoric combustion, but the expected wins aren't too big. It's good that full-flow combustion becomes more of a norm.