Re: We Went to the Moon on Feet and Inches

From: Dan DeLong (delongd_at_earthlink.net)
Date: 10/08/04 

Date: 7 Oct 2004 17:56:41 -0700

Joe Strout <joe@strout.net> wrote in message news:<joe-126C35.09015307102004@comcast.dca.giganews.com>...

> It's pretty clear to me that Joann meant "irrational" in the sense of
> "illogical, poorly designed, and Just Plain Silly" (and was referring to
> the measurement *system*, not any particular measurement). It seems
> like a pretty good description of the U.S. (and that tiny African
> country which also uses imperial units, whose name I can't remember) to
> me.
>
How about "irrational" in the sense of having the acceleration of
gravity in the middle of the rocket equation? That's because specific
impulse is in units of lbf thrust per lbm/sec propellant flow.
AAAHHHRRRGGG!! Not only does using exhaust velocity make more sense,
it helps understand what is happening. Personally, I do most of my
calculations in MKS because there is no problem wondering if a Newton
or a kilogram is force or mass. (Rant #1)

Also, it's common to call inches "SAE units" but I don't know how that
started. I am an SAE member and they are just as stuck in both
measurement systems as the rest of us. Their monthly magazine usually
has double units expressed as MKS (inch). Their specifications are
available either way. (Rant #2)

Products made in the U.S. are frequently metric simply because we sell
to the world market. Automobiles switched during the 1970s as new
manufacturing plants came on line. I had a '72 Chevy Van that used
metric engine parts and inch size chassis parts. You just have to have
a full set of tools. I stopped buying Sears hand tools because they
are offered in "Standard and Metric". It just sounds too arrogant to
me.

I buy Coke in 2-liter bottles and 12 oz cans.

Of course, the federal government takes the prize for silliness. They
regulate auto emissions in grams/mile and created a new unit to
measure heat pump efficiency. Before the "energy crisis" of of 1974,
we had COP, or coefficient of performance, expressed as KW heat pumped
per KW electricity used. Most residential air conditioners have a COP
of about 3.5. Suddenly, the feds required manufacturers of heat pumps
to display efficiency in a new invented unit of EER, which is in units
of BTU/hour per watt. (rant #3)

That's what I call irrational.

Dan DeLong

Relevant Pages

  • Re: We Went to the Moon on Feet and Inches
    ... (Rant #1) ... measure heat pump efficiency. ... Most residential air conditioners have a COP ...
    (sci.space.history)
  • Re: We Went to the Moon on Feet and Inches
    ... (Rant #1) ... measure heat pump efficiency. ... Most residential air conditioners have a COP ...
    (sci.space.shuttle)
  • Re: Air to air heat pumps efficiency
    ... what do these COP figures (and thermal power) ... those conditions, 80% of COP/thermal power vs nominal condition an air to air heat pump could be an efficient and low cost strategy for space heating, I suspect at least in hotter climates for example where the coldest temperature typically doesn't fall in winter to less than - 5 degree °C ... "Mätpunkter, utomhustemperatur" means measurement points, outdoor temperature. ...
    (sci.energy)
  • Re: Convert from Oil Heat?
    ... with water source heat pump ... with a COP of 5. ... The ground or well loop may be the most expensive part of a heat pump. ... and heat exchanger but no loop costs about $5K and uses less power ...
    (alt.home.repair)