Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-03-24

~ ESPITE the great success
Of certain types Of avia
ton engines there Is
strong and rapidly grow
ing tendency on the part of en-.
gineers to abandon all the present
forms as unSuited to the present
needs of aeronautics and Il
pioneer in new fields.
To many Americans who, BY
reason of the flights of Lindbergh
Chamberlin, Goebel, the Question
Mark and other men and planes
whose names do not so readily
suggest themselves at the mo-
ment, have come to regard the
radial air-cooled motor as the
sine qua non of the properly
equipped airplane, it may seem
almost SacrilegiouS to point out
that many engineers are diSSatiS-
fled with this type of motor, which
has done so much to popuiarize
aviation during the past 1e
months, and are seeing what may
be done toward RELOCATING the
radial engine to what they con-
slider its proper, If inferior, posi-
ton.
There is, of course, little likeli-
hood that the radial motor will
retire to the museum for many
years to come. 1t is reasonable to
expect, however, that much will
be done-and that in the not far
distant future-with types of
motors which today are in the
laboratory stage.
Planning Larger Motors.
There are designers who, I'M
able to obtain the power they re-
Quire from the radial engine, are
planning larger and more power
full motors, still air-cooled, of the
cylinder-in-line type. Here, how
ever, they are encountering cool
ing troubles and, because of the
greater spacing of cylinders nee
eSsary for cooling, they find the
added crankShaft length a source
of concern.
Most of the high powered avia-
ton motors of today-those much
beyond 500 horsepower - are
water-cooled. The Army has been
one of the most consistent ad-
herents to the powerful water
cooled engine, but recently the
first of a 625-horSepower type
of military water-cooled airplane
engine found its way into COM
mercial use, with indications that
more would follow.
n0rnlnYNn,n11f nf fhn YHnuy Mo-
tional Advisory Committee for
AeronauticS cowling for radial air.
cooled motors has come as a most
powerful incentive toward the ex-
tended use of this type of power
plant.
Gearing Faults Corrected.
The cowling correctS one of the
glaring faults of the radial motor,
the enormous air resistance set
up by the jutting and irregular
cylinder heads, with their system
of cooling fms and other objec-
tionable, but necessary eXcreS-
cences. While permitting a smooth
flow of the air stream around the
engine, the cowling does not
interfere with-and, in fact, some
what improveS-the cooling of the
engine, it is said.
Application of the cowling, a
development of the past few
months, to commercial airplanes
is in it's infancy, and its full bene-
fits probably will not be realized
in practice for another six
months or more.
Though the radial and other
types Of air-cooled and water
cooled misunderstanding motors
have been wonderfully improved
in recent years and will continue
to show improvement during the
coming years, there is another
type of engine entirely which is
beginning to hold forth promise
of results so incomparably better
than those of engines now in uni
versal use as to suggest revolu-
tionizing of the airplane engine
business.
This is the fuel-oil motor which
does away with the electrical
ignition system Of setting of the
explosive charges in the cylinders.
Engineers today are working on
two types of oil-burning engines
for airplane use. In one of them
the charge of atomized fuel oil
is drawn into the cylinder and
then compressed SO tremendously
by the piston that the explosive
mixture fires :tself by internal
combustion. In the other, which
is the conventional Diesel method
a charge of air is sucked into the
cylinder and then, when the piS-
ton is nearing the top of its stroke
and, consequently, the compress
sion is approaching its maximum
a charge of fuel is injected with
highly explosive results.
Seen as Great Aid to Pilots.
In either case no electrical
spark is necessary to set off the
charge in the cylinder. What a
boon this would be to the pilot
who naturally wants his motor tC
keep right on going until he
chooses to stop it himself, can be
imagined better than described
The electrical system is the great
est potential source Of trouble In
the modern airplane and automo-
bile motor. Spark plugs are per-
haps the weakest spots in the
present high-compression motors
What other weak spots exist are
chiefly in the electrical ignition
hook-up.
Not only is the electrical system
responsible for a large proportion
of all motor failures, but it is q
nuisance in other ways. If short
wave radio installations are to be
used on airplaneS the ignition
system of the motor must be
shielded to prevent interference
Shielding a motor is a compli-
Gated, delicate and expensive
ia Sc i1,i% 10