Evening star., 1941-04-17
40O-M.-P.-H. Wind
Will Test Models
OF New Army Planes
Wright Field Tunnel
Embodies Main Motor
Of 10000 Horsepower
BY JOSEPH S. EDGERTON.

by =.
IN a 00-mile-per-hour man.
made air blast generated by an en-
gine more powerful than the biggest
steamship power plant ever built in
the United States, the Army Air
Corps soon will begin the designing
of warplanes faster and deadlier
than any in the world today
The Army's new high-speed wind
tunnel in which this research pro-
gram will be carried on now is near
ing completion at Wright Field,
Dayton, Ohio, home of the Air Corps
Materiel Division. Devoted eXclu-
sively to problems of military aero
nautical research, it is expected to
provide an invaluable addition to
an American aeronautical research
program which for number of
years has Jagged behind the greatly
accelerated European programs.
The new wind tunnel, costing ap-
proximately s2500,00O, will supple
ment the basic aeronautical research
development carried on by the Ma
tional Advisory Committee for Aero
nautics at its Langley Field and
new California laboratories and will
make possible applied military re-
search of type never before pos
sible.
Throat of 20 Feet.
The new tunnel will provide air
speeds up to 400 miles per hour
through a throat 20 feet in diam
eter handling airplane models up to
IS feet in span or full-size fuSelages
with or without stub wings.
This tremendous blast of air will
be provided by multiple-bladed pro-
pellers or fans driven by single
10000 electric motor.
The size of this giant motor may
be appreciated when 1t is realized
that the S. S. America. largest
steamship yet built in America, is
powered with engines totaling $4,000
shaft horsepower and that even the
great battleships of the Maryland
and California classes run less than
10000 horsepower.
The motor is anchored to a tre-
mendous mass of concrete sunk into
bed rock to absorb the enormous
torque developed. At full speed the
motor requires approximately 10000
kilowatts of current. This load, If
taken without warning, would
darken thousands of homes and fac
tories in the Miami Valley of Ohio.
Special arrangements must be made
in advance to prevent disruption of
service throughout the valley, in
cluding the city of Dayton.
Only Part of Power Plant.
This single drive motor, however
is only a part of the total power
plant of the tunnel. Auxiliary mo-
tors are required to drive motor
generator sets to control speed of
the fan motor, to cool the air heated
by its swift passage through the
tunnel and for other purposes. The
total horsepower housed in the wind
tunnel power building, therefore,
amounts to 10000 horsepower
more than that generated by the U.
S, s. Maryland and three of her
equally powerful sister dreadnaughts
combined.
Flow of air through the tunnel at
maximum speed would heat it to de-
structively high levels. An intricate
cooling device has been installed
which includes the constant drawing
in of cool, fresh air from outside
and the "spilling" of heated air
automatically without loss of much
speed of the general air flow. Even
So to maintain maximum speed flow
through the 20-foot throat requires
the use of two huge propellers each
40 feet in diameter, one behind the
other. The tunnel is Sic feet in
length around a four-sided circuit
and ranges in diameter from the 90 |
foot throat to As feet. near the fans. |
The project engineers are located
In a sealed, conditioned control
room. They can change the flight |
attitude of the model at will without |
disturbing the air flow through the
tunnel.