Omaha daily bee. (Omaha [Neb.]) 187?-1922, 1910-05-15
Important Essentials for the Consid.
GRAFTON Of Purchasers.
SIZE, WEIGHT, POWER AND DRIVE
Expert TsPs ON AutO Construction
and Operation Based on va
rious Uses of the
Machine.


cars 1 do not mean different bodies, for
on that score purchaser who has never
seen motor at close quarters can be de-
pended on to know better than any one
can tell him what is most suitable for
his purpose. With the immense variety
TO choose from nowadsys-llmousne semi
limousine, landaulet, touring car, runabout,
etc.-the finer distinctions are mostly
matter of personal taste, and interchange
able bodies for summer and winter. or
town and country, are always procursble.
The chief points then for the purchaser
to consider, whatever may be his require
ments, are: Proportion of weight TO size,
horsepower, method OF drive, method Of
ignition, gearing and certain broad lines
of engine construction.
Excessive weight is, above all things, to
be avoided: tires are by far the largest
item OF expense in the upkeep of a motor
car; and the extra wear and tear.
on them means considerable and
superfluous expense There is no
reason why any car should weigh nearly
1000 pounds unless tits intended to carry
freight; the least weight consistent with
safety and rigldity is desirable.
COncerninE Horsepower.
different matter, and high rating is al
ways preferable to low, regardless Of speed
requirements One often hears a man say:
II am no speed maniac; my car is chiefly
for town use, so have no use for Excess
sive horsepower" This is a natural but
fatal error, for it is especially for town use
that power is wanted. 1t is well known that
the power of explosive engines increases in
proportion to the number of revolutions per
minute and many cars which will give
forty horsepower at forty miles an hour
will not show five at six miles per hour.
To explain this more fully, 1,5O0 revolu-
tions per minute may be taken as the fair
average speed Of a motor engine doing its
best and 800 as the lowest speed likely to
be used on the high gear; the dimlnution
| of power as the number of revolutions d.
minishes may be judged by the following
figures taken from the specifications OF
one of the most popular cars made in
| America: At 1,500 revolutions per minute,
SIS horsepower; at 1000 revolutions, SS.2
horsepower; at 500 revolutions, 30.7 horse
power; at 800 revolutions, 20 horsepower,
| and at 300 revolutions, 11.5 horsepower.
| Unfortunately most cars show a much
| greater dlminution of revolutions per min
ute 1t is, therefore, most important that
| the purchaser should knoy at what num-
Der of revolutions per minute the car is
rated. American rating means the power
developed at 1900 revolutions per minute,
| European at 600.
In hill climbing high power is similarly
desirable a car that will negotiate long
climb, like that of the well known noun
tain pass named Jacobs Ladder" with
out coming down to the low gear will be in
a much better condition when 1t reaches
the top, both intrnscally and as regards
overheating, than one that has to struggle
UP at the expense of an increase OF 80 per
cent or more in the number of revolutions
of the. engine involved in the use of the
low gear.
Drives and Gears.
OF the two methods Of drive, the cardan-
shaft has increased in popularity at the
expense of the chain-drive. chiefly on ac-
| count OF its noiselessness, and in all but the
Largest cars, ii has justified its position.
For heavy cars, however, the chain-drive
has undeniable advantages; it is stronger,
less liable to damage and moreover is
capable of repair on the road in case of a
breakdown, which a shaft-drive practically
never is, as failure generally means strip
ping Of the pinion shaft Another advan-
ltaRe OF the chain Is that the power may be
increased-of course, at the sacrifice of
speedily changing the size of the sprocket-
wheels so that on a long tour the APP
proach to a mountainous country may be
deprived of its terrors by having couple
of spare sprocket-wheels OF suitable SIZE
i'm the kit to give the power required These
/ are changed again, upon entering a flat
country where speed is of more Importance
than abnormal power.
Gears on all but the smallest of run
abcuts are invariably OF the sliding type.
Between the progressive in which the
gear-iever has but one movement, directly
backward and forward, and the ''selective''
in which IL runs In two connected slots,
and must be slipped from one to the other
in changing, the choice is mostly matter
of taste and habit; while the former APP
pears simpler to the novice, the latter is a
general favorite with experts, and is really
the easier to manipulate; but anyone. will
quickly become used to either. Many gears
are now made "fool-proof;" that is, they
are arranged so as to make it almost i'm
possible to slip in the reverse inadvertently
instead OF one of the forward gears. The
ratchet (progressive) gear lever, too, is an
advantage TO the novice, as with 1t he can
notNleave his gears imperfectiy meshed and
therefore likely to slip out, the inevitable
result OF which would be a racing en-.
sine" and the probability OF having Il
slow down and start on lower gear.
Methods of Ignition.
Between the two methods Of ignition
jump-spark and mske-and break, there Il
very little 10 choose; while the latter is les,
liable to functional disorders il is also less
easy OF adjustment in case OF failure and
II Is susceptible to wear and tear as TN
action is mechanical l would accept eithcl
method with equanimty In a car tina
suited me in other respects.
Generation OF the electric current for ig
! milton is effected in three ways, by dr.,
, cells by storage batteries Tor accumula
4 tors). and by magnetos, the last beng tn
n latest method The Disadvantages OF eacl
are that cells wear out, accumulators re
: dulre recharging, and magnetos give
[ spark the intensity of which is in dlrec
n ratio 10 the speed with which they ar
n driven. In slow running. when the hes
spark is required the magnetic is at II
worst moreover. a car cannot be startsi
with a magnetic without spinning tn
engine. With cells or accumulators II 1