The Leavenworth echo. [volume] (Leavenworth, Wash.) 1904-current, 1917-05-25


tell when the magnetic magnets Of a
car need reoharging? What does 1t
cost to have them rechsrsed?
The magnets are not weak enough to
do any harm until the action of the en-
CINE is interfered with. Should there
be an appreciate power loss and after
very thorough inspection you cannot
find the cause to be elsewhere, 1t can
very likely be in weak magnets. If tue
engine misses and there is no other ap-
parent cause il can be in weak mag
nets. If the spark will not jump one
sixteenth inch gap in the plug 1t Is
probable that the magnet Is weak. Al
though this is not sure test, it is
good indication when the engine is run
ming at slow speed. About the ayera"e
cost of recharging magnets when dis
sembled is 30 cents: when the repair
man has to disassemble them it is s
Why are the wheels Of car usually
made of the same size front and backf
They are not always made the same
size, but it is more desirable that they
should be so than of different dimen-
sions in order TO avoid carrying differ
ent sizes of spare tires and also to en-
able the car owner to shift his tires
about. thus getting greater mileage.
Will you please tell me how gasoline
and spark are supplied to rotary motors
and what their advantages are?
Gas is supplied to the cylinders of
rotary cylinder motor through mani
fold In the form of ring about the
crank shaft, which revolves with the
cylinders and from which pipes lead
to the inlet valves of each. Gas is
taken into this ring through passage
in the crank shaft opening into the
manifold or through stationary
half of the ring. The ignition distrib-
utor reyolves about stationary brush.
individual wires leading to each spark
plug. The advantages claimed for this
type of motor are lightness, due to Its
compact construction; practicability Of
air cooling, due to the positive move
ment of the cylinders through the air;
perfect balance, due to the balancing
of all revolving parts, and the station
airy crank. In explanation of this last
it must be remembered that bad bal
ance in the usual type of engine Is the
result of the reciprocatory motion of
the pistons and cranks, while In the
rotary motors the pistons revolve
about a stationary crank pin, while
the cylinders revolve about main jour
nails, eccentric with the crank pin. 1t
is this freedom from vibration and
lightness that has made this type so
popular with aeronauts.
In what respect does the American
law of the road differ from the English
law
In England all vehicles keep to the
left, while In America they keep to the
right.
Will you please explain a good meth
cd of figuring horsepower by the bore
and stroke of an engine?
The accepted method of calculating
horsepower which is used In almost
every state as a basis for taxation or
rate of license fee, does not take the
stroke into consideration. With this
formula the horsepower equals the
bore squared multiplied by the number
of cylinders and divided by the con
slant 212. Thus In a by inch en-
CINE the horsepower equals 3 multi
piled by and this multiplied by 4 las
Stunning that the engine is four cylin-
tutd Lodi nv
or 40 horsepower.
You ask for a formula in which the
stroke is a factor. The following
method meets this requirement: Horse
power equals O.197 multiplied by the
bore, and this again multiplied by the
bore minus l, multiplied by the stroke
divided by the bore, plus 2, and this In
turn multiplied by the number OF cylin-
ders. In the 8 by inch four cylin-
der engine previously mentioned horse
power equals 0.197 multiplied by 3, this
In turn multiplied by minus l, multi
Piled by plus 2, and this In turn
multiplied by 4, the resultant horse
power being 1928
In fixed spark ignition as practIeeo
on a number of cars 10 there any sys-
tenn used of advancing the spark auto
maticaIy or does the fact that at
higher speeds a fatter spark alone
solves the problemf
The term fixed spark means exactly
what it implies, although there are
nonadjustable spark systems that au'
tomatically advance the spark. In
fixed spark systems the spark occurs
usually at dead center and remains
there at all times. The relatively
greater intensity Of the current at high
speeds reduces the lag in ignition and
thus brings the actual ignition nearer
the timing at high speeds than at low
speeds. OF course a fixed spark sys
TEN never admits of actual advance
and is used only where the greater EN-
cheney and economy of the adjustable
spark or automatic spark are not deem
ed necessary or where the skill OF the
operator is not great enough TO war
rant the use Of an adjustable spark
The terms nonadjustable and fixed al
applied to spark systems should no
be confused. The one is a negative
term that embraces both fixed and au
tomato advance systems, while thu