Americus times-recorder. [volume] (Americus, Ga.) 1891-current, 1917-09-19

q Standards. 1t is expected to have
an immediate bearing in increasing
efficiency in air fighting in the war,
and probably broader bearing in
Expanding utility of the airplane in
times of peace. The walls of the test
ing chambe are the most striking fea-
ture of the ordinary observer. They
are a foot thick, of concrete heavily
reinforced iron This is to prevent
the walls from being crushed by the
weight of air at the earth's surface,
when the air inside has been rarefied
to the thinness of analtitude of 10000
feet The chamber is not large
about IL feet long inside by fee
wide and Z feet high. In the middleof
OF the floor are two wooden blocks to
form an emplacement for the motor
on test The chamber is to be covered
by a larger building, to house the
heavier apparatus, including twenty
four ton refrigerating plant and an
exhauster capable Of drawing away
1,600 cubic feet of air per minute, and
the dynamometer.
! On of the scientists identified with
working out the plans said, when
asked for a statement about the labo-
ratory
The density of the air-that is, the
mass or amount contained in each
cubic foot of space-decreases rapid
an altitude of $500 feet, the destiny
ly as we go upward At Denver, with
an altitude of about 5000 feet, the
density is about rs per cent of that
at sea level At the top of Pixies
Peak it is 60 per cent of that at sea
level At 100000 feet, the highest IL
titude at which airplanes are flying,
the density is considerably less than
that at sea level.
The power developed by an air
plane engine depends directly on the
, amount of air and the corresponding
amount of fuel that can be taken into
the cylinder at each piston stroke.
Hence if only half the amount of air
can be introduced into the cylinder,
only half the power can be developed.
AS matter of fact, the power may
be reduced even more rapidly with
increasing altitude than in proportion
t the drop in pressure.
!, Fortunately, the speed of the air
plane does not decrease in proportion
to the decrease in power of the engine,
because when the density of the air
is lessened the head resistance Of the
planes is also Iessened. Nevertheless
the decrease in the power of the engine
fixes a limit to the height that any
given airplane can attain. and the
limit appears to be present somewhere
under $4,000 feet. Yet it is in just
this field that supremacy of the air
must be attained, if at all. A pilot who
I can always attack his pponent from a
few hundred feet above has most
important advantage. Obviously, if
menas can be found to prevent the
rapid decrease in power of the engines
at great heights, our pilots win Their
by obtain the advantage of both speed
:,
ents.
Various methods and devices have
been proposed for maintaining engine
power at the reduced pressure, and
some of these have been experiment
ed with to an extent. but the develop
ment of a new engine along any of
these lines is difficult because they
could be properly tried only at high
attitudes, and the only practicable way
Of reaching these attitudes was to fly
there. Moreover, experimental test
ing Of an engine in fight is not a
simple matter, even if the pilot is also
the engine designer, which is prac-
tically never the case
ITO overcome some of the difficult
ties of the development of engines
specially fitted for altitude work, the
Bureau of Standards, in cooperation
with the National Advisory Committee
for Aeronautics, is just completing
what we call, for lack of better
name, an altitude laboratory. The
engine to be tested will be mounted
stand pressure of ton 10 the foot
on the outside This room will con-
tain refrigerator coils, to absorb the
heat from the exposed parts of the
engine, and fans for circulating the
cooled air over the engine and past the
cooling coils.
THE pressure in this chamber can
be maintained at any desired point