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Re: Excerpts & Comments

To: Bob Palmer <rpalmer@ames.ucsd.edu>
Subject: Re: Excerpts & Comments
From: Steve Laifman <laifman@flash.net>
Date: Wed, 07 Oct 1998 19:13:45 -0700
Bob,

As I recall, my XK 120 had a 3 inch bore and a 4 inch
stroke.  Talk about piston speed at high rpm.  Why, you
might ask, when the most knowledgeable designers are
building low bore/stroke ratios of 1 or even less, would Jag
build one in the 'wrong' direction.  Because they were
stupid?  No, much more practical.

I remember my tour of England, and the guide's explanation
of all bricked-up windows in London homes.  Seems the
British taxed the homes based upon the number of windows.
So the owners bricked them up, avoiding the tax.

Well, the British civil service engineers believed that
there was only one induction (breathing) capability, so all
power was derived from a single BMEP (brake mean effective
pressure, or effective combustion pressure at ignition, over
the area of the piston.  So, to penalize the wealthy, they
taxed the horsepower of the car.  This was easy for them to
figure out, it was based solely on the bore.  This formula
of bore and BMEP became known as "Taxable Horsepower".  The
car manufacturers, on the other hand, knew there was no
substitute for cubic inches, so they just increased the
stroke to make the power.  Thus, ridiculous engineering for
reduced taxes.

I am not so sure that the reasons for all the effort to
compare apples and oranges in this rod length issue isn't
based on justifications of deeds done.  Too many variables
and too few equations.  Can't be solved by arguing.

Steve
--
Steve Laifman         < One first kiss,       >
B9472289              < one first love, and   >
                      < one first win, is all >
                      < you get in this life. >


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