Edwards air show B-1 speed record attempt

On Fri, 24 Oct 2003 23:57:02 GMT, Gene Nygaard wrote:

On Fri, 24 Oct 2003 09:12:12 -0700, "Tarver Engineering"
wrote:


"Gene Nygaard" wrote in message
. ..
On Fri, 24 Oct 2003 08:15:17 -0700, "Tarver Engineering"
wrote:


"Gene Nygaard" wrote in message
.. .
On Thu, 23 Oct 2003 12:46:36 -0700, "Tarver Engineering"
wrote:

snip
Why not "pounds", like an aircraft?

Because there are too many engineers too stupid to understand the
simple fact that those pounds are, by definition, units of mass
exactly equal to 0.45359237 kg.

I find it unlikely that there are many engineers that can not operate a
calculator.

Show me a calculator that will figure out *which* pounds are being
used, so that they get converted correctly.

Aircraft already have units of measure. Why use different units? Why is
anyone working in NASA Operations that does not know aircraft units?

What you write is a non-sequitur.

You also underestimate the effects of systematic miseducation. The
mere existence of a conversion factor from pounds to kilograms on a
calculator isn't going to undo the fact that some favorite teacher has
drummed into someone's head the notion that pounds are always units of
force and not units of mass, so you can't really convert between
pounds and kilograms. In fact, in today's screwed up world, there are
a number of textbooks which tell you just exactly that.

Why change from the units of aerospace to some other arbitrary set of units
in the first palce?

Because it is the interdisciplinary and International System of Units.
There is no reason to have to learn different units of measure for
each activity we engage in.

Such changes have taken place in the past, of course. But when the
air speed indicators of many aircraft were changed in the second half
of the twentieth century, they weren' t changed to metric. Instead,
they were just changed from one Fred Flintstone unit to another.

That's about as silly as if the United States were to change now from
inches of mercury to millimeters of mercury for altimeter settings.

In my 20 20 hindsight I can say for a fact that
attempting to apply si units to aerospace has come at the cost of confusion
and we are very fortunate to have avoided toumbstones.

In fact, the calculator is the end of any need to change to si
units, as si is a slide rule reality.

Any time you make a conversion, at least other than by factors that
are exact powers of 10, you lose something.

Perhaps, but not enough to matter from an engineering, of operational
standpoint.

Certainly enough to matter.

Often the "something" which you lose is the sense of how precise a
measurement is.

Any time there is a need to make conversions, it is an opportunity for
all sorts of other errors, including misentry of the numbers into the
calculator, transposition of digits in copying the result, or
whatever.

In that case, why stray from what already works and play silly SI games?

Because there is only one way to get rid of the need to do
conversions:

You are right, when do you intend to start the conversion to the inch??

Al Minyard