Originally Posted by Ostrich
Al,
Actually Dynojet is correct.
All they are is measuring horsepower.
Horsepower as a unit of how much work was done. They know how much it weighs, they know how long it took to spin it up to the speed that they know, and from there they can calculate the amount of work (horsepower) done, and where it was done.
This is why you need an RPM reading on an engine to get a correct torque reading.
how the actual force being applied to the roller is torque, but the roller is not measuring the instantaneous rate of change and the torque being applied to it. It only has to measure the amount of time it takes to spin the known mass up, and with that it calculates horsepower.
Exactly....but you cant make a drum that large and fill it with concrete or whatever is in it to extremely close tolerance so that one calibration fits every drum. I am suspecting they have something back at the factory that applies a known Tq to the drum to calibrate each drum. My point is you cant DIRECTLY measure HP like you can TQ. Even the dynojets HP measurement is a calculation of HP based on time and acceleration which in turn was calibrated back at the facory with DIRECT MEASUREMENT of tq applied to that specific drum.
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Last edited by HybridSS; Apr 27, 2005 at 07:10 AM.