More non-efi Horsepower stuff

[Matthew Prater]

Hello,

First time poster.  Mainly a list lurker.  Not enough money to start a efi
project right now so I am just trying to absorb info.

I'm a senior ME at Michigan Tech Univ.  I don't really care for fluid or
thermodynamic studies, so I haven't learned them well.  I'm more of a
dynamics type guy.

If this is all repetition, please forgive me.  I subscribe to the digest
form of this list.

ANYWAYS, about this horsepower equation issue; the REAL definition of power
is Power=Torque*angular velocity, ie hp=constant*trq(ft-lb)*rpm.
Now, the farthest I've been able to get in decifering this British system
chicanery is that one horsepower = 550 ft-lbs/sec.  That is taking into
account that your measure of angular velocity is in radians per second.
It's pretty hard to get a physical feel for a rad/sec so we do it in
revolutions per minute, which means we have to multiply by 60 to get to
rad/min and we have to divide by 2(pi) to get to rotations because there
are 2(pi) radians in a revolution.  Walla we get the following:
1 hp = 1 trq(ft-lb) * 5252 * 1 rpm.  Equation manipulation shows that the 
hp=trq(ft-lb)*rpm/5252 is true.  That is as far as I can get with the books.
So, as four years of MTU schooling has taught me, I must move on with the
romantic hope of getting a grip on this.

To the persons who work on steam engines or have TLCs (Toyota land cruisers,
which, I might add, are cool little units which have the respect of many 'o
wheeler) don't try and apply this equation to your motor.  It would hold in
space with friction et al = 0, and if you were really board you could
probably make a mathematical model of your motor and show that if it did
indeed rev up to 5252 they would cross _around_ there, and then one of the
big three would pay you millions of dollars for your work, which would
involve roughly 12 variables for every dollar the USA is in debt.

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?
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?

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).

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.

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.

Thanks.
Matt

Matthew L. Prater / prater at mtu.edu / http://www.me.mtu.edu/~prater/
Ford fanatics visit Fo.Mo.Co @ http://www.me.mtu.edu/~prater/ford.html