Here is a picture of a Merlin engine on a test stand. To the right of the nozzle, the black and sooty exhaust of the turbopump can be seen. https://old.reddit.

Here is a picture of a Merlin engine on a test stand. To the right of the nozzle, the black and sooty exhaust of the turbopump can be seen. https://old.reddit.com/r/engineteststands/comments/8f7c1q/merlin_engine_loxrp1_static_fire_test_by_spacex/ https://old.reddit.com/r/engineteststands/comments/8f7c1q/me...