# How are the constants in hydraulics calculated? [closed]

I would like to know (out of sheer morbid curiosity) how constants in hydraulics are calculated. The constants are, for good ol' 'Merican units; 63025, 5252,and 231. These constants came out of "Introduction to Fluid Power." The constant 231 is how many cubic inches are in one gallon.

The equation for input HP is HP = (T * N)/63025. Why is '63025' used? Does that make sense? Basically I'd like to know where these units came from? I'm not sure if I explained my question better. I believe one of the responses I got pretty much hit the nail on the head.

## closed as unclear what you're asking by CuriousOne, mpv, John Rennie, Kyle Kanos, Norbert SchuchMar 1 '16 at 18:13

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• Could you please specify what are these constants and where have you seen them? – mpv Feb 29 '16 at 20:13