The Oskaloosa herald., 1915-09-30


applying brakes to lock the wheels OIL
applying greatest possible brake strair
without locking wheels? And will {
heavy car stop in as short distance al
light one, the, speed and brake power
being equal7
1t, is generally supposed that a mo
torcar viii stop in shorter. distance
| II the. wheels are not fully locked, bu
almost so and, revolving. When tbs
brakes are applied so. the wheels loci
the only friction tending to stop the
car is that Of the. tires on the ground
| but when the brakes are applied so al
nearly to lock the wheels there Is roll
Ing friction of the wheels, gear set and
rear axle friction and brake friction
hence with the greater friction the
car will stop in shorter, distance. II
you VIII watch street car motormen
whose cars are equipped with all
brakes or locomotive engineers al
work you will find that when the con,
veyance. is to be stopped the brake
control is alternately applied and re-
leased, thus setting and releasing the
brakes, which prevents the wheels
from sliding. This not only tends TO
keep the vehicle from moving off the
track, but stops 1t in shorter distance
than. il the. wheels had to slide on the
tracks.
or two cars exactly the same, In ev-
cry respect. except as to the load car
ried, the, one with the lighter load will
stop in the. shorter distance. This may
be attributed to the fact that the in
ertia of the heavier. vehicle is greater
than that of the lighter. II you We're
pushing a baby buggy at ten miles per
hour you could very easily stop it
within few yards. but II you were
pushing a 300 pound cart you would
lind it would require greater distance
in which TO stop.
What pressure is, counted good com.
preston in a cylinder?
Good average practice Is about sew
enty pounds to the square inch.
wish, to paint black the brass, fiN-
lures on my car, but have no recipe.
Can you inforrn me how ! am to do this
work? dc 49,
Fuse eight ounces Of asDhaltum and
fiye.tenths of an ounce Of dark gum
anime, adding fifteen ounces of Ihseed
oil. Then one and ive-tenths ounces Of
dark gum amber, having been preTi-
Ously fused with three ounces Of lin
seed oil, are boiled and added to the
first mixture. The boiling should be
kept up until little Of the mass when
cooled becomes plastic. Now stop the
heuting and add two and five-tenths
ounces Of turpentine, The paint can
he applied with a brush and requires
no enameItng,
Can you tell me the best fireproof
material to use in the construction OF
a earase7
Although concrete is considered bet
ter than other material for this pur-
pose, consultation with a prominent
builder brings out that cheap and eff
cient flooring can be made with cOm-
binatiOn of hollow tile and concrete.
The tile is placed In rows and about
five inches left between each row. Into
this space concrete is poured and re-
enforcement Of plain round rod used.
The main advantage of this construc
ton is that 1t Is light In weight and
cheaper than concrete alone. 1t has
proved satisfactory in practice. 1t is
claimed further that the air spaces In
the tile act as an tnsulator against heat
cold and noise.
How can a motor designed for a GER
tain voltage do any pulling at all when
connected up TO current either twice
or only half as much az the designers
figured ONT II is understood that the
generator supplying current is one Of
low voltage, probably about thirty-t"e.
An electric motor designed to operate
normally at thirty-two volts, for exam
pie, viii operate at Voltages under thlr-
ty-tw0, but the speed will he reduced
considerably. 1t also may be operated
at slightly over thirty-two volts proyid-
ed the designer took this into consid-
GRAFTON In the windings Many elee-
tric vehicles are operated by simply
changing the voltage across the motor
terminals, this being accomplished
either by inserting resistance In the
line or by altering the battery connec-
tons SO that either series or parallel
connections may be made with various
numbers Of batteries. However. a mo-
tor designed to operate at thirty-two
volts maximum would burn out IL the
voltage were doubled, just as a 40 volt
lamp would burn out II inserted In a
go volt circuit
While my engine is idling with the
clutch in or out q dull thump may be
heard. This comes at irregular inter
walls. Can you explain thls7
The thump undoubtedly is from the
motor, since by declptching the clutch
everything behind 1t remains still. A
loose bearing might cause a thnmp
and loose fiywheel might emit the
same sound.
What Is thu best bushins fer vslvs
stemg7
Brass or bronze seems to be the best
valve stem bnshing. These metals are
soft comparatively. ana the wear be
~. y 49, -