I sent this to SAE in connection with Stan Jakub's letter.
Hope a couple of these messages will begin to reverse the SAE's drift
away from SI to which Stan referred.
Bill
===================
Dear Editor:
Let me second the thoughts of Mr. Stan Jakuba who recently wrote to
you regarding the use of SI metric units in the Automotive Engineering
magazine. More and more Americans (and virtually all non-Americans)
are quite conversant with the SI metric system. Furthermore, the use
of SI units simplifies much of the relevant data and especially
comparisons of one quantity to another.
It might be useful to show some of the material in the Olde English
units, given parenthetically after the SI version, for the benefit of
some of your readers. Those readers may still enjoy using
measurements from the Middle Ages instead of the modern measurement
system used by 95% of the world's population. However, sooner or later
those readers are going to encounter that 95% and they will need to
have at least a passing familiarity with SI metric in order to
communicate.
In particular, for energy, the use of joules (J), and its multiples
and submultiples using the SI prefixes, is recommended, to replace the
confusing plethora of miscellaneous and incommensurable (as well as
incomprehensible) units that are extant. Similarly, watts (W) and its
multiples and submultiples is preferred to the use of non-metric power
units. The use of joules and the use of watts are related, of course,
since power is just energy divided by time (W = J/s). The relations
between the large conglomeration of non-SI power units and the equally
large conglomeration of non-SI energy units makes the use of SI units
even more desirable. There are fewer combinations for comparison and
each combination is related more simply.
Thank you for your attention. I hope that SAE and Automotive
Engineering magazine will continue to make progress in the use of SI
units in all phases of your operation.
Regards,
Bill Hooper
retired professor of Physics and Engineering at
The University of Virginia's
College at Wise.
