More non-efi Horsepower stuff

[Ken Mayer]

On Sun, 23 Feb 1997, Matthew Prater wrote:

[snip]
> To those who may know: My official newbie questions...
> Is this brake horsepower?  Methinks it is.  If it is, what is a real
> horsepower?  What is the difference?  How stupid is this question?
> In other words, is a brake horsepower different from a normal horsepower in
> how it's measured, or are they different units?

There's brake horsepower (measured at the flywheel), net horsepower
(accounts for accessory loads and friction losses in the drive train),
shaft horsepower (for turbine engines).  A horsepower is 550 ft-lb/sec of
power. (torque is units of lb-ft)

> For trivia's sake: who decided that 550ft-lb/sec roughly approximated what
> a horse is capable of?  What foul machine produced this?  Did some crazy
> guy give Mr. Ed a big torque wrench and have him spin a few cycles with
> it on some sort of active resistance machine?

Remember Mr. Watt, inventor of the steam engine?  In order to compare what
his machine could do with the power source of his day (the draft horse),
he experimented and determined that the horse could lift 550 pounds 1 foot
in 1 second.

> You'll have to forgive me, I am pretty strongly opinionated about English
> units vs. metric.  I would write more about it, but I am a little tied up
> converting from pound mass to pound force from slugs per gallon, while
> trying to account for solar flares in the equations (a little silliness
> there).

And then there was Mr. Fahrenheit.  He invented a mercury filled tube
with some arbitrary hash marks.  In ice water the mercury column was at
"32".  In boiling water it was at 212.  In his wife's mouth it was at 98.6
(seriously).  It's really not all that bad.  We could be using furlongs,
scruples and fortnights as a measurement system. <g>

> Here's why I like metric units.  1 Newton Meter /sec = 1 Watt = 1 Joule/sec.
> Poetry...  Someone along the lines applied the KISS principle.

The metric system has been the official measurement system in the United
States since the 1700's, under federal law.  The US was one of the first
to adopt it. The abomination of inches, feet, quarts and gallons are
defined in terms of the metric units.

> Sorry for the long letter...  I would have checked the web-page for
> answers but believe it or not I don't have access to a web browser right
> now.

Ken
:-)