[net.space] Horsepower & rockets

karn (05/13/82)

Can somebody explain to me how the measure "horsepower" is relevant
to rockets?  I guess you could look at the raw energy content of the
propellants, or the kinetic energy/second imparted to the propellants,
but the useful output of a rocket is force, not force*distance/time,
which is power.  For example, if I bolt a rocket to a test stand,
it generates zero horsepower, no matter what the thrust.

Of course, it would be reasonable to measure the output of
fuel pump turbines, APUs, etc in horsepower, since they resemble
conventional engines.

Phil