Evening star., 1917-09-28
VACUUM CHAMBER CONSTRUCTED
j FOR TESTING AIRPLANE ENGINES
Experts at Bureau of Standards Able to
Simulate Atmospheric Conditions at
Z Elevation Of 10000 Feet.

In The shadow o: little knoll out at
ths bureau OF standards Is a modest
otucco building which may be epochh
IN the development of aerial nayiga
sion-
It contains a vacuum chamber for the
testing of airplane engines at atmos-
pheric conditions ranging from that
encountered at sea level to that found
at an altitude of 10000 or more meet
IT is the product Of months OF study
and the ingenuity of many experts. In
about a week It will be ready for its
unique work.
Probably because 1t is considered well
for the public to know that its govern
ment is not asleep IN meeting the prob
lens of modern warfare, and the reali-
xation that 1t won't help the Germans
much to know the Same thing. per-
mission was given q Star reporter to
obtain a description Of this unique ap-
paratus-
For Peace and War.
This is just one of g number of high
1y interesting experiments being con-
Quoted Just now at the bureau OF
planned. are related to peace-time
progress well as war. So it is with
this one. A representative of the
Handley-Page aeroplane building, re-
Gently IN this city, predicted that the
big planes which have been circling
about Ostend, travelling from London
TO Paris and to Rome, will cross the
Atlantic regularly after the war And
the United States is sustaining Its fun
share OF the effort to develop sky tour
ing, both for war and peace functions.
Attention of government aerial ex-
perts first was directed to the problems
of high altitude navigation when the
French and British missions came to
- t-~~ ~%a-, ,1oI0 thA til
quota Of the French scientific mission
stress the necessity OF developing some
means of testing engines at attitudes
higher than the 1000 or 5000 feet, at
which the difference in the atmospheric
pressure and that on the ground level
Is negligible enough to be neglected in
flying. Allied machines in skimming
over German territory. must rise to
10000 feet or so. At that height the
air pressure Is half. or less than half,
that at an ordinary level. Hence the
engine used generates. under such con-
ditions, only half as much power. So
the national advisory committee on
ae-onautics and the bureau of stand
ards set to work on the problem of
testing engines for use at such an alti-
tude
No Mountain Available.
The obvious way would be TO take
the engine aloft. That would be risky
Also the aviator usually is not the de-
signer, and the formers observations
would be sketchy and perhaps mac
curate. Moreover, even If an expert
were aboard time would not be suffi-
cient to observe fully the air. fuel, oil,
water circulation, power production and
the numerous other points involved.
Another way would he to take the en-
Eine to the top of a 2o.O0G-foot noun
tain-and mountains have been util-
ized abroad-but the United States has
no mountains to fit the experiment.
The third alternative was to simulate
as nearly as possible, earth, condi-
tions of 2o,000-foot altitude, so the
bureau experts set about bringing the
mythical mountain to the mechanical
Mahomet.
To do that test chamber was de-