Norwich bulletin., 1916-01-25

motor broader ability, smoother ac-
ton and less noise. All the work done
in this direction has been influencing
one principle. the principle OF splitting
heavy stresses into lesser ones. The in
frequent. smashing power-stroke of
the one-cylinder motor, delivered once
to every four. revolutions of the n.y.
wheel, exerted such strain and re-
quired such construction as were in
compatible with economy and comfort,
| and early brought about the Develop
ment Of the two-cylinder motor. In
this type, one power-stoke was deliv-
| fywheel, and the chief disadvantage
of the internal combustion engines
were lessened by half
In the same way, and at various Pc
RODS. the two-cylinder motor went
out before the four, and the four, in
| turn, similarly was superseded by the
| six For considerable time the six
| cylinder motor seemed completely to
satisfy engineering aims, but reasons
gradually were discovered which made
it seem advisable to split up the driv-
ing force still more.
A six-cylinder motor is theoretical
ly in perfect balance and vibration
less. But in actual practice this ball
greater or less extent by the weight
of the pistons of the motor. Each
piston pushes and pulls on the crank
shaft as 1t rotates, and the pulls and
|
vfbratory influence just as long as the
crankshaft remains absolutely stiff
| and true. But let there be ever so
slight a. twist in the shaft-let the
] center of gravity Of the piston move
| even by the tiny fraction of an inch
and as once we have vibration that
| is detrimental to the motor and I'M
| pleasant to the passengers.
This result is in no way due to ex-
plosive force. but to the weight of the
Init hal cd 90 (-<1 80 q,
crank. 1t is an engineering truth that
| doubling the area of piston more
than doubles it's weight. Conversely
| If we halve its area we do more than
halve its weight. But If we are to
have a greater range of ability and
i preserve the advantage OF balance we
| must have more pistons. And as soon
as the effect Of many small pistons OF
light weight and many explosions of
small intensity is noted other advan-
tages are apparent With the reduce
| ton of strain through the motor
through using many pistons to get the
| required power, we save not only pis-
ton weight, but f1ywheel weight, crank
| shaft weight and crankcase weight
| Further, we get more power from an
engine of the same total size of capac-
ity in cubic inches than Is possible in
| a six of a corresponding standard OF
engineering. This is because the light
piStOnS and connecting rods allow the
engine greater range Of speed, while
the smaller bore of the cylinders per-
mits the use OF a higher pressure, and
the higher the compression the more
efficient the burning Of the gas at all
speeds.
Naturally the first step onward from
a six Is an eight. And to preserve the
advantages of short, stiff crankshaft,
almost sacrificed in a sizeable six, and
| to enjoy the benefit OF q short light,
stiff motor, the v or twin-type of mo-
tor construction suggested itself. Once
developed, the twin-four revealed GER
tain advantages when compared to a
six of similar size and power. So far
as the character of the torque or turn
ing effect, Is concerned, the twin-four
motor has an advantage over the six
by reason Of the more frequent inn
pulses of lesser intensity. Another
advantage concerns weight, particu-
larly in the crankshaft and flywheel.
All things considered, it Is plain that
along with the acknowledged ad-
vantages derived from the twin-four
reappear these characteristics of the
signed to overcome. The logical ad-
vance from the twin-four is the twin
six type of motor, since 1t preserves
the theoretical and practical balance
of the six, and by use of smaller pis-
tons and cylinders removes these
factions with the six.
1t is clear that the torque of the
| twin six motor must be 100 per cent.
better than the single six. Six power
strokes per crank shaft revolution
blend together so closely as to make
it possible to distinguish any pause
between them, even at very low engine
speeds, as when pulling through traf-
fic on up grades. Its operation can
best be likened to the action of steam.
In weight the twin six is lighter than
the single six, and SO far as accessi-
| bility Is concerned is quite as salts
factory.
Aside from the structural advan-
tages with this type of motor, its SUI
periority in performance is so pro-
nounced as to make is a most signi-
fcant factor in motor development. 1t
is more nearly than all others the per-
feet result that all automobile engi-
neers would attain in ability, smooth
ness and silence. Its perfect balance
its lighter parts, the higher compress
sion possible and the improved car
| buretion due to uniform suction, result
in noticeable gasoline and oil economy
to the user.
OF course actual service is the only
real test of a motors serviceability
and in this regard the twin six has
even exceeded expectations. 1t has
been very gratifying to us to watch
the trend of motor development in
Europe for air craft purposes, where
the prime consideration has been re-
liable, economical power with the least
possible weight. For this very i'm
portant service the II cylinder motor
has steadily been supplanting other
types since the beginning of the war
and is the most desirable and sought
after type of motor for air craft pur-
poses in existence today. In thus es-
tablishing its supremacy for air craft
work, the IL has had to compete with
every other known type of motor with
the result that the engineering skill
Of the world has been involved.
This Is the time of the year that
difficulty is liable to be encountered in
starting the engine. When the car is
equipped with an electric starter, con-
tinuous spinning of the motor will
soon run down the storage battery. A
sure method Of preventing extra tax
alton of the battery is to provide some
reliable printing arrangement.
The chief duty of the motorist le
to determine that the battery Is fully
charged and that the electrolyte fully
covers the battery plates. There Is nc
danger of a fully charged battery
freezing. The specific gravity should
be tested by hydrometer at least
once every two weeks. The reading