On 2020-01-18 17:17, Jeff Findley wrote:
In article ,
says...
...

Out of curiosity, how do they measure how much thrust is produced by
each engine? A sensor that measures pressure against the wall of the
engine bell? An electronic scale measuring "weight" of engine against
the mounting brackets of the stage?

Or is thrust assumed from speed of turbopumps (fuel flow)?

You'd have to ask SpaceX.

Indeed, but I would (naively, perhaps) assume that the pressure inside
the combustion chamber can be directly (mathematically) translated into
thrust, as long as the shape of the throat and bell remain as designed.
The thrust is determined by the exhaust flow, which is determined by the
chamber pressure (and the ambient pressure)

Perhaps there are some subtle thermodynamic effects in the
compression-expansion process that depend also on the temperature and
molecular composition of the gases, and on possible last-chance
combustion after the chamber, but I would assume that those are
secondary to the effect of chamber pressure.

--
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
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