The raptor is a "full flow staged combustion engine" https://en.wikipedia.org/wiki/Staged_combustion_cycle#Full-flow_staged_combustion_cycle https://en.wikipedi

The raptor is a "full flow staged combustion engine" https://en.wikipedia.org/wiki/Staged_combustion_cycle#Full-flow_staged_combustion_cycle https://en.wikipedia.org/wiki/Staged_combustion_cycle#Full-f... AFAIK it's the only flying, non-research example of such an engine.