Chapter 10
The Grand National was the
sport version of a machine that began its existence as about the most ordinary
car that could be built. It was targeted
at the market of commuters and mothers.
While the job of commuting daily up to an hour each way was a
substantial task for a car, the real wring out came when Mommy had to drive the
children to school on a cold morning.
Mommy’s interest was in getting there quickly – things are always late –
and not getting the children excited by racing the engine. She would learn just how hard she could mash
on the accelerator without shifting the car into a lower gear and just when she
could lift off a fraction to shift the car into a higher gear. And this is the way she always drove.
Under the circumstances of a
cold day, high power settings and low engine speed, a normally aspirated
automobile engine will gulp as much cold dense air as it is capable of,
particularly if the car has been asked to deliver peak performance before the
engine itself is hot, as is usually the case.
That meant the greatest amount of oxygen possible is in the cylinder at
the moment of ignition, and with proper admixture of fuel, the forces developed
in the engine are at an absolute maximum.
Add to that chuck holes and unpredictable traction on recently salted
roads. If anyone can break an engine, Mommy
can.
With a hungry market for its
work, the engine developed into an extremely tough mechanism. It had crank shaft, connecting rods and
cylinder walls beefed up for the challenge.
Then one day they decided to
try using a computer to regulate the amount of fuel put into the engine under
such extreme conditions.
Now as an internal combustion
engine gathers speed, at a constant open throttle setting, at first the torque
– the force delivered by the engine – rises.
Then an engine speed comes when the carburetor cannot deliver an optimal
amount of air-fuel mixture in the time during the engine cycle when the intake
valves are open, and the amount of energy released per ignition falls. The torque falls, but the power keeps rising,
since the engine is delivering more cycles per second.
For maximum power the engine
is run in the high end of its designed speed range. But it is not developing maximum torque. That happens at slower engine speeds, and any
engine must be tough enough to handle maximum torque or it will promptly destroy
itself.
Under the control of the
computer, the engine of this car had a torque curve that ran straight
across. It could deliver maximum torque
in any part of its performance range.
The greatest effort a laboring engine must make is to use its power to
propel the car forward. But part of the
power must be used to accelerate the moving parts of the engine itself. And as the car runs through its gears these
parts must be accelerated repeatedly.
The car must work hard to get out of its own
way.
With a normal toque curve,
the car at maximum horsepower is accelerating metal it is not actually
using. Not so the Grand National. It uses all its strength all the time.
The result was a car that
would out accelerate other cars that had more horsepower, less weight and were
better streamlined. By the time the five
were roaring out of Randleman, high end exotic cars routinely were computer
controlled, but the vans never had a chance.
No more vans appeared. They pulled off the road briefly so
By early afternoon they got
to the
It had been one of the many
battles between the Confederate Army of Northern Virginia and the Union Army of
the
So they decided to dig a
tunnel and blow the rebel line up. With
monumental labor the sappers dug their way all the way across the battlefield
and placed kegs of gunpowder under the Southern position. They did their work well. Even today you can see why it is called, “The
Battle of the Crater.” The blast hole
cleanly split the southern defensive works.
But as the sappers dug, the
Southern soldiers heard it and reported it.
Men were sent to dig listening chambers close enough to the advancing
tunnel to eavesdrop on the unfolding events.
This accomplished two things. For
one thing the Army of Northern Virginia knew exactly when the charge was set
and the fuse ignited. For another thing
the chambers absorbed some of the shock of the blast, although by no means
enough to prevent the opening of an enormous hole in the ground.
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