The Oskaloosa herald., 1916-01-13

What final ratio Is considered best or
cars with SO by 4 inch tires, and what
speed should be obtained from this
ratio2
The size of the tires is not the all
important factor in determining the
proper gear ratio, as there are many
other points to be considered, such as
the most efficient speed of the motor,
the weight of the car, etc. These may
so alter the proper gear ratio that the
mere size of the tires becomes insig.
nihcant in determining the final re-
duction. With this in view, 1t is i'm.
possible to state that any given final
reduction is best fer a given tire size.
have changed the 80 by 8 inch front
wheels and tires on my car to 80 by 3L2
in order to have the same size all
around. How much more than a mile
will have to travel before the speed
oneter registers one mile? .-.
Unless you have replaced the entire
wheels you should not have changed
your 80 by 3 for 80 by 31a, as the rim
profile for so by 3 tire is different
from that of 80 by 81. In changing
your equipment from 80 by 3 to 80 by
312 on the same wheel it would be nee
essary to cut the felloe Of the wheel
one-half inch all the way around and
buy a new rim Of different profile.
Without changing either the wheel or
the rim you can use a 81 by 3h tire, I'm
which case the distance travelled by
the car would be 3.33 per cent greater
than the spcedOmeter reading would
show. II you change the wheels and
rims and use the 80 by 31h size In place
or the 80 by your speedometer read
ing would not be affected.
What Is the setting of a magnetic on
racing cars in seneral7
In general. the timing for a racing
motor is advanced from one to two
teeth on the timing gears ahead of
touring practice. The exact number of
degrees Of advance will depend upon
the make of magnetic, and hence no
definite rule can be laid down for this.
but where 1t is common touring prac-
tice to have the full retard occur on
upper center in racing motor, the
full retard position will be advanced
one or two teeth on the timing gears.
Can you give me formula for a so
luton to be used in soldering aluminium
as nuriatic acid 10 with sheet from
The flux generally used with alumni
mum Is chloride Of zinc, but with the
solder you speak of this might not
prove to be the best.
Where is the best place for the spark
plug in any type of engine?
The best place in the combustion
space for spark plug is at the point |
If purest mixture. This will vary with !
liferent types Of motor, owing to the
differences in shape in the combustion
chambers. The reason for this is that
where the charge is less diluted by
lnscavenged gases 1t will burn quick.
st and surest.
Some engines stop almost inmedi.
IteIy after the switch is cut off, while
'ther engines seem to lose their mo-
nertum gradually. Why is this?
When the switch is cut off Oh an en-.
Inc 1t Is merely a matter of bringing
D rest the moving parts which are no D
)nger propelled by the explosion of
he gases in the combustion chamber, {
'nly one influence is probably great
nough to be considered es the oppos-
lg factor to the movement of the mo-
Or, and this is the internal friction.
'hen this has eXerted its influence to
lch an extent that the motor is I'M =
Die to turn itself over against the COM =
ress1on or the cylinders it will come 3
rest. The compression is not an op- Is
osing factor unless the momentum Is
to carry the motor over top
inter, because when 1t is carried over :
p center the expansion Of the COM :
'essed air gives up practically all the .
'wer which was utilized in compress .
g 1t. If the compression We're used
fore the engine will be unable TO N
I'm itself over the dead point. With G,
csc considerations it will be easily Ifs
en- that a motor with tight bearings. d.
INT piston rings and high compression 81
i'll come to rest much quicker than m
e which has the opposite conditions. oil
What factors determine proper valve ~
rnensions? ca
Che method for determining the St
'per size of the valve depends upon Oh
; gas velocity through the valve and m
} piston speed. Gas velocities are da
culated on the basis of piston speed LIZ
a full opening of the valve.
~ wi
When an inflated tire 10 in a station do
: position at which point is the high. M,
pressure? 80
he pressure is the same throughout Isl
tire. 1t is one of the fundamental,,15l
gsical properties of gases that when we
mass of gas is inclosed in a vessel il col
'rts a uniform pressure against ev. int
square inch of the surface of the 70
sci and also that at any point in the hei
d mass the pressure Is the same I'm Coz
ry direction. Were this not so the ~,
es In the tire would not be in go,
te of equilibrium, and hence, al me
UGH the fra maa ofakln-.~ A. -