The Hawaiian gazette. [volume] (Honolulu [Oahu, Hawaii]) 1865-1918, 1899-03-28

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. |HHI. Um.Hr .H .H. ra.s and fH.
. |fUH NIuIIun caused d. HIN There
|ifF un I0assa Hfafttpf Loo fHHsu. .0H
af 4. ifs laf NJ ftH trolley com
T, irfrH0f ~ simply q pumping snfIns ln
which thr nuid d. cir Instead ~ water.
ITHH cImpfsasfd a'f ftHifm ran there.
fIfa hl operated by the same GLASS Of
mon thnt rln run locomotive or a
mill engine The air motor IN the OR
car 'a similar in design 10 that 81 lo-
locomotive Certainly n0 simpler device
can bu imagined than this nor one
moro easily Kept In repair 1r Jess U.
able 10 get out NJ order
Tho operation ~ ON air car D. much
| simpler than that NJ an electric car. Il
| requiring but q slight motion % the
wrist 10 bring the car from full speed
90 o dead stop I'm an electric motor
| there Dr. first 20 Doe operated an cleo
Itrin switch. and then the brake This.
ls one Jf the most important adyani-
lagos U' compressed air. iUasmuch as
There o. less liability Df damages re-.
IsIliIug from Injury tD property and 70.
| lie. This has been actually demon
Is.Fatod by the air motor cars that were
Ioperatcd for one year sn l2Jth s., New
York city.
| Electric people point out as a danger
the high pressure carried In the stor-
age tanks on the air cars As already
stated the bursting OF one of these
| tanks will not throw any metal, and,
unless q person was directly on the
point Of break, no harm would be
done. Those who have seen men and
horses burned 10 death by the breaking
OF a trolley wire. have not much to say
regarding the safety Of the trolley sys-
TEN. Furthermore, the rapid strides
made In the perfection of the strength
Of materials has reached a very high
point, Steel tubing Is made by several
large manufacturers in the world, the
material Of which is guaranteed to.
stand a test inside OF the elastic limit
Of 1900 pounds, the bursting pressure
being more than 5000 pounds. The
pressure carried in street car work in
these storage tubes Is but from 20OO
TO $500 pounds, giving factor Of safe
~ OF about four. Were water used
under this pressure, the factor of safe
~ should be greater because water Is
InOn-COmpressible. Air, however. being
an elastic fluid, Is entirely different
and nothing can occur by its use sim
liar to what Is known as "water-h ham
mer," or acknowledgements. occurring
in use of water under pressure. There
Is not as much danger In using an air
pressure Of $500 pounds. as there is
in a boiler pressure of 100 pounds. One
hundred and eighty pounds. steam
boiler pressure, Is being used in several
of the pumping plants in these Islands.
| The writer knows that there are
movements on foot In several OF the
large cities towards the installation OF
air motors for city and suburban work
and predicts that in less than three
years the air car service will have
strong public approval. II must be
taken into consideration that there Is
a large amount Of money at present in
vested In electrical equipment and that
the cost to investors to change their
present systems would be enormous
However, public sentiment and lower
cost Of operation will soon cause COM
pressed air 10 be Installed
a point of advantage Of the Hardie
system of air cars is that the pound
on the track is much less than for an
electric motor Of The same weight
This Is due to the difference OF the
blow OF a spring supported and OF a
lrigidly mounted load When passing
al. tf.. 4t. 81
inch In height at a speed OF ten miles
per hour. the blow struck will be about
seven times harder for an electric
motor than for an air motor. There
fore. for the same weight of rail the
streets Of a city will not be dishgured
as often in the case of the air system
as with the electric.
There are several forms of air mot
ors, the writer much preferring the
Hardie on account of its mechanical
simplicity as well as economy in oper-
alton.
To sum mp tcrsely: II Is an indie
pendent motor, under quick control,
noiseless. at reasonable cost. of high
efficiency, free from danger and OBJ
jectionable features. II Is the most
economical system in cost of installa-
ton, operation, and maintenance. It
has been thoroughly tested, both win
ter and summer, and Is endorsed by
many Of the most prominent engineers
in various parts OF the country 1t is
for this reason that the writer, at the
request OF many friends. has written
the above article in hopes that 1t may
be Of some assistance in determining
Tor the people OF Honolulu what street.
car system they will eventually adopt.
II. 4. ALLEN.
Mr.. Allen is a graduate of Annapolis
land Is consulting engineer with Fraser