Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-01-12

planned, the interior of the watel
Jackets is washed with a sub
stance on the order of liQuiC
glass, which closes up any hole!
through which water might leak
The ethylene cooling compound
however, disSolveS any such coat
ing and runs through.
Development OF a comfortable
pitch and reversible pitch propel-
Ter for use on Supercharged air
craft engines designed for high
altitude work is another impor-
tant experimental project now in
progress, Gen. Fechet said. Such
a propeller may be expected to
reduce the length of run needed
for take-off, increase the rate OF
climb and improve the all-around
performance at high attitudes.
Compromise Search Fails.
No fixed-type propeller blade
which is efficient in the heavy air
at ground level is efficient at the
high attitudes in which modern
military planes must operate. The
effort in the past has been to OBJ
tain compromise type, which
was not always good for the take
off and which would give only
fair performance at extreme alti-
tudeS. The adjuStable-pitch pro-
peller may be set for efficiency
on the ground and then ad-
justed for efficiency at any given
altitude.
Development of the aerial
camera has been going forward
steadily, and during the past year
the Air Corps camera of the Fair
child KS type has been used for
photographs over distance of
227 miles. Capt. Albert w.
Stevens OF Wright Field, flying at
an altitude of $4,000 feet over
Northern California, took a
photograph that distinctly shows
Mount Rainier, near Seattle,
Wash.
A heavy red filter is used, the
filter itself being so thick that
the fllament of an incandescent
light bulb scarcely can be made
out through the red screen. The
emulsion is so sensitive, however,
that an exposure of only one
fiftieth of a second, through the
filter, is used, the penetration OBJ
tanned being due to the infra-re
ray.
Rays Pierce Cloud Banks.
Through employment of the
infra-red ray and its penetrative
powers, pictures now may be made
through clouds which obStruct
ordinary vision, according to Gen.
Fechet. Vertical pictures, made
from an altitude of five miles
through clouds which form a
complete barrier to vision are so
clear they will reveal persons
walking on the streets, he said.
AS result of the development
Of higher compression aviation
engines, the use of ethyl gasoline
on a large scale will be necessary
during the coming year. The Air
Corps expects to use approx
mately IS per cent plain gasoline
and IS per cent ethyl gas. The
new high-compreSsion motor will
not run on ordinary gasoline, it
was pointed out.
An example of the destructive
effect of ordinary gasoline in the
new motor occurred when the
old-type fuel was burned in a new
bombardment plane motor. The
engine was ruined in short time
through the defamation of the
low-grade gasoline before the
proper point was reached in the
compression stroke.
Liberty Motor Passes.
The past year has witnessed the
final passing of the famous Lib
erty motor as standard installa-
ton for Army planes. The Lib
erty was the American wartime
production motor and has been
used continuously since that time,
small changes in detail having
been made from time to time.
The appropriations bill for the
current year forbids the pur-
chase of any airplane equipped
with Liberty or any other en-
CINE purchased or built prior to
July /, 1920.
One of the important Air Corps
developments of the year was the
development of a bombardment
plane which may be used, with
minor changes, as a commercial
transport plane. This is the first
case in which the Air Corps has
been able to adopt a truly con-
vertible plane, one which might
in case of emergency be con-
verted from a commercial to a
military plane, either on the pro-
duction line at the factory or at
the repair depot from planes
actually engaged in commercial
aviation at the time.
This plane is the heavy bonn
bardment plane, known to the
Army as the "B-2" and to COM
mercial aviation as the "Curtiss
| Condor" The Condor is a twin
motored biplane using 600-horse-
power water-cooled engines. AS a
transport plane it carries Is pas
sengers. Conversion of the trans
port plane for bombardment use
is made possible through the fact
that there is no nose motor to
! interfere with visibility and that
the plane is properly balanced for
the carrying and dropping OF
| bombs.