Re: Translation...
part of the problem may be the use of H2 rather than kerosene. The Saturn V first stage used kerosene but all other stages used liquid H2.
As I recall some of the problems with using liquid H2 in the first stage has to do with the fact that it's at an extremely low temperature, which causes material problems. Metals get brittle at cryo temperatures, and lubricants "don't". It's not so bad when you're operating in a vacuum or near vacuum, at least as I understand it, but at sea level you have moisture accumulation and the engine nozzle is somewhat of a compromise since it has to operate at atmospheric pressure as well as a near vacuum, and everyplace in between.
To get fuel into the engine at the necessary volume and pressure, you need to have a high volumetric flow turbine-powered pump. And apparently that's what broke. I think they use reaction-style turbines.
(unfortunately this site requires javascript to view the content)
https://airandspace.si.edu/collection-objects/rocket-engine-turbo-pump-cutaway-f-1
Anyway, my understanding is "it's tricksy" and Elon avoided it in the 1st stage, deliberately. And so did NASA back in the 60's. Probably for the same reasons.
I would guess the fuel tanks would be smaller as well, though the 1st stage would weigh quite a bit more when fully fueled, using kerosene rather than liquid H2.
Biting the hand that feeds IT
