New-York tribune., 1918-09-29
Mechanic Says Air Mo-
tors Can Be Adapt
ed to Road Cars
By Frank F. Tenney
West Side Y. W. c. A.
School for AirpLane Mechanics.

usefulness for flying. Already there
are many thousands of used engines ac-
cumulated at every flying field in this
country and at all of the aviation bases.
Not all the airplane engines shipped to
France are demolished in the course of
war. Reading the papers. one might be
led 20 believe that sooner or later all
airplanes are smashed beyond repair
or drop within enemy lines. But far
the greater number are retired because
they are no longer effective.
When one is told that the average
life Of an airplane engine is 100 hours
it is startling. People who are prone
to find fault because that endless
stream Of Liberty planes is not wing
ing across the Atlantic will please take
note of this fact. Even were there no
other obstacle, the fact is that the trip
would take one-third or more of the
life of the engine before it reached the
fighting line. The prolonged strain OF
a trip Of this kind might further
shorten the life Of the motor.
May Be Sole Supply
But the fact that an engine is no
longer Of value in a flying machine does
not signify that it has no usefulness
for other purposes In fact, this may
be the sole source Of supply of auto
engines for some time to come-at
least, until the war is over. The ques-
ton naturally arises whether the air
plane engine is suitable for auto pro-
pulsion. Well, it was not designed for
that purpose, and in some respects the
ideas Of the two engines are diamet-
rically opposed, but it is not only fea-
sible to put used aero motor in an
auto, but it already is being done.
Here are some of the differences be-
tween the two motors. which weigh for
and against the substitution. The aero
! engine is made very light, just as light
as they dare make it, and is bal
anced to nicely. Lghtness is essen
tial, as will be appreciated, but the bal
ancing eliminates much Of the vibra-
ton experienced with the auto engine.
The latter rests upon a sturdy steel
frame riveted firmly together and sus-
pended on springs and through these
and rubber tires on the ground. The
aero engine. rests upon ignt-almost
fragile-bed, supported by struts and
wires to wings which rest upon the air.
Just as the auto motor was better
balanced than the stationary gas en-
gine, which was mounted on solid
base, so the aero power plant must be
! lighter and more finely balanced than
/ the auto engine. Again, there is more
care exercised in building the aero en-
gine. It must be perfect because it
must be more reliable. The driver
cannot get out on a cloud to
doctor up the aero engine, as the chauf-
feur gets out and gets under when
L. l. Il
of aviators climbing up to the engine
to see what the trouble was, but 1
doubt the. truth of the story. Engine
trouble means get to earth, if possible
safely; you get there anyway.
/ mentioned the fact of the lighter
construction and the finer workman
ship. The fact is that the factor of
safety is lowered almost to the vanish
ing point, bun the scientific construc-
tion offsets this. TIE auto engine is
not designed with reference to safety
table; it is not necessary.
Aero Engine Is Simple Type
The aero motor is likewise much
simpler. In all types except the Lib
erty motor they use magnetic ignition.
There is no battery ignition, or practi-
cally none, SINCE 95 per cent use the
magnetic. At the last automobile show
there were only q couple OF cars
equipped with the magnetic. They have
sel--starter systems and battery igni
tior. The airplane engine has no self
starter. In a few cases it was tried,
but doubt if many are in service to-
day There is no use for the self start
er. The engine does not stall in the
air. If it does-good night. 1t either
runs or doesn't; if the latter the ava-
tor, if he tried to operate starter,
would lose control of the plane, doubt
less, even if he did get the engine run
ming again.
Then the lubricating system is much
more highly developed than in the auto,
though some builders are devoting
much attention to this feature lately.
This is one of the elements of greater
safety. 1t is not more oil that is
needed, but positive supply under all
conditions. Oil must flow to the bear
ings no matter what The position of the
plane may be, and in the Hispano-
Suiza and perhaps others the carbure-
tor feeds gas and the fabrication works
even though the plane be upside down
for considerable period.
said that after 100 hours of flying
service the engine is scrapped. 1t may
be ~ exceptional cases that an engine
may reach 200 hours. This does not
u,
they are unsuitable for air service for
several reasons. They begin to loosen
up, as it is called, and the aviator does
not want to take a chance. The valve
cages, for instance, are very thin and
sometimes they are ground through,
but there are many where this is not
true. 1t is not so good a seat, perhaps,
and there may be loss of 20 or 80 per
cent of power, but this loss can be dis
counted.
Some of the parts may be crystal
lized. In rare cases almost the whole
engine is crystallized. Parts break
from this cause at times. Where
it develops the engine is unsafe
for air work; where the engine
runs under a full load practically all
the time the aviator is off the ground
and breakage would mean loss of life.
The auto seldom runs under full load,
and II there was break it would mean
Inconvenience rather than danger.
Power Loss Is Not Serious
The loss of power referred to is not
SO serious as it would appear offhand
A set of dry cells which runs down too
low for ignition purposes will do for
door bell for long time and will run
several lights Tor a considerable pc
Rod. We have Curtiss engine in our
school for instruction purposes which
we got after 1T was no longer safe for
flying. 1t has been in continuous SER
vice with US for ten months and still
has lots Of kick in it. 1t has run at
! y III lo,, hJ