Evening star., 1933-12-17

ana DullulIlS VI IIlcSe dlIpld1lcS
interests of national defense. 7
chance that their new airplane
them quantity contracts.
Because of the economy pre-
longer is able to encourage the |
since it can offer no definite asst
for purchase of airplanes even if
AS a result there now are only three
military types of airplanes being de-
signed in this country to meet the
requirements of existing Air Corps di-
receives. Two years ago there were 1e
types in progress.
THE seriousness of the situation can
not be overemphasiZed in view of the
developments going on abroad" it has
been stated by Maj. Clinton w. Howard
chief of the Materiel Division of the
Air Corps at Wright Field. Dayton
Ohio, the great proving ground for new
Army airplanes.
Pointing to design competitions for
pursuit airplaneS recently conducted
both in France and England and to a
program for the development of a new
type of bombardment airplane inaugu-
rated in France, Maj. Howard declared
that this presents situation which this
country cannot afford to ignore in view
of the time required for experimental
work on new types
Experimental al-metal airplanes now
used for tactical types, Mai Howard
explained, require at least three years
for design, construction and testing
The enforced idleness of our military
constructors during this period will
place the Army Air Corps in a most
unfavorable position within two or three
years, since it can be expected that
some of the new models now being laid
down by foreign countries will result
in a marked increase in performance
over standard airplanes We now have OF
are about to place in service
Only at the expense of other activities
in view of the enforced idleneSs OF
Wright Field personnel for an average
of SO days each, has the Materiel Di-
vision been able to continue its work
on aviation engine projects, regarded as
fundamental necessities.
Work at the field and abroad indicate
that there soon may be radical change
IN Air Corps policy relative to the
fueI injection, exhaust-driven super
chargers for air-cooled types, aero.
dynamic development of the ring COW
and improved fuel with lower specific
consumption, all have favored the re.
placement of the liQuid-cooled engine
by the air-cooled for military types.
Only one new liquid-cooled engine
has passed the preliminary or design
stage and is ready for type test, while
there are three sizes of the double-rov
radial engines which have been devel.
oped which now appear to have a place
in the Air Corps engine program.
Propeller studies have kept the Ma.
ter1el Division busy during the past
year. These studies have included rea.
sons for propeller failures in flight due
to resonant vibration frequencies in the
metal Of the propeller coinciding with
the engine explosions. resulting In ia
tigue" and crystallization and ultimate
breaking of the blade.
Noise Reduction Sought.
With clean airplane structures anc
suitable exhaust mufflers the propeller
today is the chief offender as a noise
producer. Reduction of propeller noise
is very important item in contribut-
ing to the success of night air opera
tionS against an enemy objective de.
Tended by anti-aircraft forces. The
division, therefore, also has been hare
at work on this phase of propeller de-
sign. The work of silencing airplanes
includes the design of propeller blades
having wide, thin tips and working at
high angles of attack along the blade
With tip speed well under 900 feet pei
second, from so to rs per cent of the
noise reproducing energy IS eliminated, ii
has been found.
The comfortable propeller Is be-
coming mandatory for new types of air
planes, Maj. Howard reported Geared
engines, necessary for high efficiency
and reduction of propeller. noise, to-
gether with the wide speed range, re-
suit in very undesirable take-of anc
climb characteristics which can be elm.
mated only by application of a suitable
comfortable propeller. The Air Corps
is working on three such types.
Among the airplanes which have
gone from the service test classification
to standard use In the Air Corps dur
ing the past year are the fast new
Martin Bio and Biz bombardment
airplanes, the Curtiss Ala attack
plane, the Douglas 0-43 corps observa-
ton type and the Boeing P-26 pur-
suit airplane
Both of the bombers include i'm
provements over the test types which
make possible more efficient functioning
of the crew. The Ala includes i'm
provements found to be necessary as a
result of service test. These changes
have somewhat reduced the high speed
The structure of the O-43 has been
changed to provide a straight-wing
type in place of the gull-wing in the
test model. Only minor changes, in
cluding q landing gear of lighter and
cleaner design, were made In the P-26
Airplanes now in service-test status
include the YO-40A and B models OF
corps observation type, produced by
Curtiss- Wright: the consolidated ALL
attack airplane and the YP-30 pursuit
airplane. It has been the policy Of
the Air Corps to utilize commercial