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Marc,
That brings up a related point. Even if I were a
qualified engineer (which I'm not) I would still procure a complete engineering
review of my plans before I started ordering materials and
components. The farther upstream one can detect and correct an error
or oversight, the cheaper it is to correct. I think I have some
talent as a designer, but as that great philosopher Dirty Harry one said, "A man
has to know his limitations."
Jim
In a message dated 12/9/2010 9:48:14 P.M. Central Standard Time,
piolenc@archivale.com writes:
On
12/10/2010 9:20 AM, Les & Anna wrote:
> Just a couple of
thoughts, as with Doctors talking with their trained
> terminology,
likewise, Engineers and the like, to those not in the field
> it does
sound complicated,
> inherently increased by those same professionals
not having that other
> specialized field of knowing how to impart that
knowledge.
In some cases, professional jargon is deliberately
overcomplicated to
exclude lay persons. In others, serviceable terms
understandable to
laymen are set aside in favor of those understandable to
other
professionals speaking other languages. Medicine is an example: a
Russian doctor often has less trouble understanding an English doctor's
diagnosis than does his English patient.
Anything that one doesn't
understand is by definition complicated. When
somebody speaks a foreign
language, it always sounds as if he's talking
very fast whether that is so
or not. The only remedy is to learn the
language.
> It is all in
the way it is presented .....as a suggestion; would it not
> be simpler
to give an example of a simple workable format and then the
> related
maths to confirm how it was established so that individuals can
>
reverse engineer a simple format to assist them to understand the
>
principles, maths and calculations easier, to apply to for more
>
complicated formats.
There are limits to the degree to which a problem
can be simplified.
More on that below.
> i.e.. A simple example
if you like, to help them visualize and get an
> indication of exactly
what is involved.
> eg. If someone in the club, engineering orientated,
could, for the
> exercise, apply this to;
> a simple cylinder say
1200mm diameter x 4meter long, no tapers
> include two normal round end
capsno other orifices
An example of simplification that isn't.
Intuitively, hemispherical end
caps on a cylinder should give the simplest
structural solution and the
lowest stress. They don't. The stress state
where the caps meet the
cylinder is very complicated and very high. The
optimal structural shape
is different and requires some grasp of higher
math to comprehend.
> What this does for the layperson is give them
a perception of size,
> shape, steel dimensions, weight etc.of what they
should be considering
> ,which also acts
> as a reasonable check
to their later calculations with tapers and other
> shapes, and conning
towers, considering dynamic loads etc.
I'm not sure this is so. I think
it would tend to give a false sense of
security, instead, and lead to
possibly fatal errors.
In my consulting work I often run into people
who try to scale up a
model airplane, say, to full size and think that
anything that works at
one scale will work at another. The first time I
encountered this I was
floored; I had been immersed in dimensional
analysis for so long that I
forgot this was not the normal condition of
Mankind. Explaining dynamic
scaling laws doesn't always work, and you just
have to let reality prove
itself. That's okay if it's a model airplane, or
if the only consequence
of error is that a ducted fan's thrust doesn't
meet expectations; if
your life is at stake, it's probably
unacceptable.
> They then have an idea of what expectations should
be for the
> environment they are calculating for .........*a base line
if you like*.
Baselines are only useful if the person using it has a
grasp of the
correct process for proceeding from that baseline to the
scale of his
project. Unfortunately, that is "complicated"...and
crucial.
> How much volume a 1000litres of liquid takes up,the
weight of a 1000
> litres of liquid etc.
A thousand liters has a
volume of...1000 liters! The liter is a unit of
volume, after all.
Everybody outside the USA should have learned in
Elementary School that it
equals 1/1000 of a cubic meter, and that the
volume was chosen such that
one liter of pure water weighs one kilogram.
the size and weight
of appropriate batteries etc.
Here is one area where a repertoire can
be useful and not misleading.
Such data are routinely used in
weight-sensitive applications like
aircraft - there is even a Society of
Aeronautical Weight Engineers
(SAWE) that publishes tables of typical
weights for various items. I
have some excerpts from their old lists that
include such exotics as
kapok insulation, corkboard and so forth for
estimating the weight of
cabin furniture.
One psubs FAQ topic could
be Weights and Volumes and include entries
ranging from formulas used for
first-order estimates to actual weights
of specific apparatus, by brand
and model.
Best to all,
Marc de
Piolenc
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