At 04:21 PM 10/8/98 -0600, Theo Smit wrote:
>And I forgot wrist pin offset...
>
>Is this topic bludgeoned to death yet?
>
>Theo Smit
>tsmit@novatel.ca
>B382002705
Theo,
All but the most ardent gear heads, I'm sure, are hoping for a quick end to
this Masters Disseratation in Advanced Automotive Engineering so we can get
back to doing our real work - like helping Scott restore his ID plates and
stuff. But how can I let the Mayf have the last slanderous word; to wit,
"I find fallacy in some of the comments to (sic?) Dr. Bob."
And this, coming from a man who, by his own admission, had no clue where a
full 1/3 of the energy output of his engine was going. (It's going down the
driveshaft Larry!) Now, all kidding aside, what we have here is a classic
example of the orthogonal universes between the mentality of physicists and
engineers. Fundamentally, physicists are very simple people, whereas
engineers pride themselves on just how complicated they can make things.
Working in harmony, they make a great team, but when at odds it can get
downright silly. Now, from my point of view, engineers are great as long as
there are one or two physicists around to occasional point them in the
right direction. And they're also great for making up all sorts of handy
tables so you can look up things like logarithms and cosines and stuff like
that. But their weakness is, they often miss the forest for counting the
trees. Given that the Mayf 's thinking is orthogonal to mine, I admit to
being a bit confused about what he considers "fallacy", but I'm guessing it
goes back to the following quote: "the reduction in reciprocating weight
translates to a power increase, since less energy is required to start and
stop the pistons." Now, even trying real hard to be charitable here, I have
to interpret this as saying that all of the kinetic energy acquired by the
piston on each stroke is somehow wasted. I don't think even an engineer can
read this any other way - am I possibly interpreting this statement wrong?
I don't see that he's talking about stress/strain or any subtle parasitic
effects which was the tangent the Mayf proceeded to take. Consider this;
suppose we take just a short block and lubricate it with a zero viscosity,
zero friction, super-lubricant. Now, start the whole crank assembly
spinning. Without friction, it will just continue to spin; pistons going up
and down, up and down, up and down, ad nauseam. Hey, what happened to all
the energy it takes to start and stop the pistons? Like I said, we
physicists look at these kind of problems in very elementary terms. It may
not be the end of the discussion, but it's usually a pretty good place to
start.
Having (probably not) the last word in San Diego,
Bob
Robert L. Palmer
Dept. of AMES, Univ. of Calif., San Diego
rpalmer@ames.ucsd.edu
rpalmer@cts.com
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