The sun. [volume] (New York [N.Y.]) 1833-1916, 1910-07-20
.4EROPLANE ENGINES.
IAshtness and Economy IN Fuei Less Inn.
pOrtant Than TrustweFthiness.

Potomac River with Glidors OF his inNen-
ton and q small steam engine whose weight
Was something like twelve pounds horse-
power gave riss to the Idea that only a
motor OF much lighter weight hOrSe-poWer
Was required 10 transform the glider into
! a successful power driven machine. but
now that such a motor Il available through
the perfecting of the Internal combustion
| engine u - found that extreme lightnesS
though desirable u not altogether essential.
! and In fact an engine OF Twelve pounds
horsepower. " fitted TO one Of the best types
OF aeroplane to-day. would carry II with
a pilot into the air
II has lately been seen that a biplane can
lift three passengers besides the pilot over
short distances. while two may he carried
| with ease. Assuming the combined weight
OF the three passengers TO be t7O pounds,
this Is equivalent to an allowance OF more
than eight pounds a horsepower for n 81
rse-po~er engine. In addition to the actual
weight OF the engine. which would be three
70 four pounds n horsepower. While
| therefore the ultimate achievement Of
dynamic night was due to the lightne~s Of
| the Internal combust ion engine In relation
70 the power developed. subsequent expert.
ment has demonstrated how to improve
| the efficiency Of the sustaining surfaces
and to diminish head resistance TO such an
extent ~ to make extreme lightness In the
motor desirable only on the score Of freight
4 carrying capacity
| The competing claims Of freight capacity
| and % motor trust worthine@s as insured
by duplication Of parts with consequent in
crease in weight. will lie determined by the
objects sought in the design Of the aero
plane. Saving Of weight In the motor. how
ever. permits the construction Of more
compact and controllable machine than
| would he possible II the susta ming surfaces
were designed to carry considerable dead
weight. and II IL toward a compromise In
| these respects that the design of the motors
| II tending
! The original motor used by the wriRh,
brothers was comparatively heavy and
crude for the power developed. but with the
large sustaining surfaces with which the
early machines were fitted this extra vel ht
was nv M means q disadvantage. since with
| = motor constituted on the lines Of an auto-
mobile engine " enabled them without
undue risk 10 carry on experiments which
| resulted IN all round Improvement In the
| machine The result OF experience now
shows that the Aeroplane proper. methods
! Of stabiliZinE and control. and construct ion
generally. are more highly developed than
the motor. which suffers from some palpa-
HE defects that must CirCumscribe the use
fulneSs Of the machine until tho Increasing
atten' ion q directed In the subject has wrou ghl
the improvements which are desired
To Rsin freight carrying capacity the
weight Of the motor horsepower must
he kept low. bnt without any sacrifice IN the
certainty OF its working. and the IDEAL
motor. like the one boss shay Of oliver
Wendell Holmes. should 10 constructed
throughout With such a regard To the saving
Of weight that all parts should have the same
factor Of safety for the stre-Se. that come
upon them. Considerable doubt still exists |
a. 90 the best size and type Of propeller |
and therefore the efficiency Of he propelling !
mechanism a. a hole must remain indeter-
inmate hat the lack Of definite rules upon
which 20 design propellers need not inter
fere in the problem Of the motor engineer |
who has to provide = constant power AZ The |
propeller shan With small weight Of motor !
and adequate strength
A. present he sirnan j. more concerned .
with trustN orthiness Of running than with
economy in fuel and he - content I o expend |
= gallon NJ petrol IN tTaver~inR only twelve !
miles n by 50 doing he can secure infAIli- |
hil'v IN the motor upon which his safety !
depends In this respect the design OF \
aerial motors - unlike that Of The motor ,
car engine, where economy forms one Of |
The compel ing claims Of he manufacturers
Leading alrmen have expressed the he !
lief that night viii be- possible with motors .
Of less horse pow r IN the future than are |
htied 10 acceptance to-day. and when the .
experiments ~ the National Physical Lab
orA'ory on propeller- have been concluded
The reasons for this prophetic utterance
may heroine apparent The low thrust a |
horse power ~ due 10 The Ignorance at |
present existing a. TO propeller design
Like the marine turbine. the aerial engine
runs too fast for the best propeller -peeds
The Wright bTot hers overCAme this dim.
Guilty bN he scmeN hat unm."hAnicaI e1pe-
dent ~ chain gearing one chain being |
crossed French nrm has utilized the
half lime cam shaft NJ the engine suitably /
enlarged. TO drive the propeller thus get.
ting speed reducti ION OF two 10 one hut |
the Antoineite. FarmAn and Voisin type.
continue 10 drive the propeller direct with.
out reduction " i probable that the ~.
re"l drive will prevail for any form Of gear.
ing. however simple. Introduces an element
Of risk With doubtful benefits
The elimination OF the dead weight Of a
hNwheel nv ~" rotating cylinder motor Ia
some advantage in favor Of the prtnci.
pie. IA addition 20 the efficient cooling
" i perhaps TO le regretted that British
manufacturers hAv" not devoted more AT.
isntion 70 this type Of motor which has .
claim =" IN" earnest attention and study
or engineers The heavy rotating ma.
provided by the cylinders ha- n .teadying
effect on the machine. and the fact that the
cylinders and connecting rods revoIVe
each In 10 own circular orbit. eliminates
the results of reciprocAtins parts while tho
perfect balance Of the motor can be ea.ilv ~.
'ained. any departure therefrom being coun.
teracted BY s'rewing the sparkling plugs in
or out for the necessary adjustment
One difficulty or the TO, a,lns engine 4. IN.
lubricAtIon. and until some mean. OF reduc.
ING the consumption OF ubricat.ng oil ia
devised the rotating cylinder motor rnust
have at least one compromising defect
On occasions Ike the London to Ma |,
q hester flight the us. of' large ouan,tI.-
OF hhrica'ing oil may not matter but in
an everyday motor for the aeroplane in
the hands Of tho chauffeur or what.ys,
hi- aerial equivalent may be called the L
!ubricstion must he relied upon more ,h.n
n the motor car. for while failure in the on.
case means only incon venieHce. IN IN. o,h.r
It may entail disaster.