New-York tribune., 1919-05-04

& production Of aeropianes i:
mainly governed by the out
put by engineering firms Of the en-.
gines required for the aeroplanes
which can be constructed in a given
time, says the aeronautic CORE
spondent of "The London Times"
Even q single-engine aeroplane re-
uuires more than one engine to main
tain it daily in the air. One engine
is required as 4 spare under repair
and one ready repaired to replace
the original engine fitted into the
machine. For civil flying it will
probably be found necessary to have
q proportion of one to two spares for
each single engine machine and
uroportionate number for multiple
engine machines. Consequently, our
capacity for producing engines is
very important and requires immedi-
ate consideration.
The main consideration in design
ing al aeroplane engine for war is
the maximum amount Of power for
the minimum weight, irrespective of
cost Of the manufacture of the en-
CINE or of the material. So far has
this been carried that the designer
has been allowed to reduce the weight
by cutting down bearing surfaces to
the finest possible limits, with the
result that the number of hours an
engine will run without overhauling
has been greatly reduced.
In designing aeroplane engines for
civil purposes considerable modifca-
tions will be necessary, and in all
probability bearing areas on cranks,
shafts, connecting rods and other
wearing parts will have to be in
creased from 25 per cent to so per
cent. In most engines this will en-
tail an appreciate change in design,
and in any case the designer of the
aeroplane engine for civil purposes
viii have to consider reliability as
well as light weight and the best
possible performance. Although
power for weight is of the utmost
importance in war, it is not as i'm
portant in civil flying.
Generally speaking, for ordinary
commercial transport work it will
not Re necessary for machine to
fly above 5000 feet, and it is evident
that the height Of from $4,000 feet
to $4,000 feet, at which aerial fight
ing has been mostly carried out, will
not be required for civilians. There
will be, however, cases where in
long distance routes high mountain
ranges viii have TO be crossed,
when greater heights than the aver
age must be reached; for these
routes engines can be specially de-
signed.
II building engines for civil fly
ing the main consideration will be
reliability. If the government in
tends 70 use commercial flying mo-
tors for military purposes when oc-
casion arises, weight and reliability
viii require very close investigation
to determine whether definite stand
ards can be laid down and engines
which conform to these standards
subsidized From the results OBJ
tanned in the bulk production Of
both aeroplanes and engines during
the war it would appear that it is
more necessary TO subsidize the en-
CINE than the aeroplane for the fol-
lowing reasons:
1t has been found possible to
change the production Of a high
c4ass engineering firm from its
usual peacetime output to the man
ufacturirg Of aeroplanes in quanti-
nes within six months, but it has
been proved that it is practically
impossible to obtain quantity pro-
anction Of aeroplane engines from a
Arse eiass car engine building firm
IL leas than sig months, and in most
cases Il has been eighteen months
before any real quantity production
has been arrived at.
It ia eYident. therefore, that the
engine Il the first part Of a ma
chine II be considered for subsidi-
zatlon, and this brings one at once
10 naturalization in it's broadest
zSfktTt IL nrdar 4h1% ey,<r;ros ~