Evening star. [volume] (Washington, D.C.) 1854-1972, 1930-07-06
.HE mightiest gales ever pro-
duced by man will begin
blowing for science and the


duced by man will begin
blowing for science and the
progress of aeronauticS at
Langley Field, Hampton, Va, next
Winter, when the 60-foot wind
tunnel now being constructed by
the National Advisory Committee
for Aeronautics is completed.
Through the great mouth of the
tunnel, measuring go by 80 feet,
the air will be forced at speeds of
from 100 to 10 miles per hour by
two 30-foot propellers, each driv-
en- by 1000 horsepower engine.
Though higher velocities have
been produced in wind tunnels,
no such volume of air ever has
been moved at such speeds In any
tunnel in the world.
Completion of the tunnel, it is
believed by many in the aviation
industry, will mark the beginning
OF new era in the study of prac-
tlcal aerodynamicS and, therefore,
In the progress of aeronautical
design and construction. The 20
foot-propeller research tunnel at
Langley Field, now the worlds
largest, made possible experiments
which last year won for the COM
mittee the Collier trophy, award
ed for the greatest achievement
in aeronauticS each year.
Aid to Plane Building Developed.
In the 2O-foot tunnel the now
famous N. A. c. A. cowling for ra-
dial air-cooled engines was devel-
Oped, and the results of these
studies are being applied to air
plane construction throughout the
industry with highly beneficial re-
suits. It is possible that results of
even greater Importance to every
person who flies will be achieved
In the big tunnel now under con-
6truction.
Though the committee has had
many requests for studies to be
made in the 60-foot tunnel, it is
considered likely that the first in
vestigation will be in the nature
of a checking of observations of
airplane characteristics in free
flight against those to be obtained
by mounting the same airplaneS
in the wind tunnel.
For the first time it will be pos
sible to study under laboratory
conditions the precise effects of
air flow on a complete airplane
The immense difficulty of making
observations of this character in
free flight will be overcome in the
tunnel, and for the first time, it
Is believed, it will be possible to
find what actually happens when
air flows around all parts of the
modern airplane at flying speeds.
Present Utility Restricted.
At present it is possible to make
wind tunnel tests only of portions
of airplanes or of airplane mod
els. Even though the models are
made with the most precise accu-
raglan accuracy which is car
ried to the thousandth of an
inch-the results are not accu-
rate. This is due to the fact that
though the airplane may be
scaled down accurately enough,
the air flow cannot be scaled
down. The same air flows around
the model as around the airplane.
There is scale effect which must
be Celebrated. In the celebration
there is opportunity for error. In
fact, it would appear error is in
evitable.
To overcome scale effect, the
National Advisory Committee de-
signed and built the present vari-
able density wind tunnel, in which
air passing through the wind tun-
mel and over the model may be
compressed. The results were
found to be much more accurate
than those obtained with models
in the ordinary tunnel. There
still remain errors, however, which
cannot be entirely overcome until
the big tunnel is completed.
Tunnel Foundations Complete.
The foundations for the big
tunnel have been completed and
the steel framework is approx
mately IS per cent completed.
Completion of the building and
tunnel by Thanksgiving is posi-
bic, though 1t will be at least De-
cember l before the tunnel is
ready for operation, it now is be-
lieved. The structure adjoins the
present propeller research tunnel.
Beyond it construction crews are
at work on the 2,500-foot seaplane
test channel, which is to serve for
Seaplane and flying boat floats
and hulls as wind tunnels serve
for airplaneS.
The problem of supplying suffi-
cient current for the operation of
the great tunnel has required
thorough study. At present cables
carrying only 10000 volts are laid
to the field. This is insufficient
to operate all the present tunnels
and machinery at one time, and
staggered schedule must be OBJ
served. The two great motors for
the new tunnel will draw at least
a 23,OOO-volt supply.
Special Gables Provide Current.
Special cables to provide cur
rent for the motors are being laid
by the local public utility COM
pany to a point separated from
Langley Field by a narrow inlet
OF Back River. Across this inlet
the supply cable will be laid under
water. Laying of the special ca
BILE, however, is only a minor
problem. So great will be the de-
mands of the motors for current
that the utility company will be
able to supply them only when it's
normal loads fall off. The motors
can be run only at times when the
demand for current in all the