Evening star. [volume] (Washington, D.C.) 1854-1972, 1934-06-10


gas, and read a large thermometer dial
800 feet above his head, which will tell
him the temperature of the hydrogen
gas-a vitality important bit of informa-
ton to the balloonist, since the lifting
power of the gas Is directly affected by
temperature changes. Many portfolios,
for observation and other purposes, are
provided. Through one opening an
oblique camera will operate; through
another, in the bottom, the great YER
tical camera will point. Another will
house a drift indicator for the use of
the pilot in working out his navigation
problems.
A peculiar and extremely important
opening in the bottom, only an inch in
diameter, is that through which ballast
will be dropped. Through it will pass
more than three tons of tiny lead shot
as fine as mustard seed. Only shot
must go out; not any of the life-giving
air. The problem is complex. 1t was
solved by an ingenious two-Story hop
per, the lower inclosed and alright.
arranged so that the shot passes
through a double air lock.
THE gondola has been tested for leak
age by being filled with water under
a pressure of 40 pounds to the square
inch and by being left for "a hours
with an interior air pressure of 20
pounds to the square inch. Inside are
many shelves for the dozens Of pieces
of scientific apparatus, batteries, oxygen
TASKS and other paraphernalia.
The gondola will be hung below the
balloon in a sort of sling or cradle.
the bottom of which Is a broad metal
hoop fitting closely against the shell,
to which will be riveted 10 metal bands
extending upward and also hitting close
to the shell. Around these bands an
other hoop will be placed to hold them
tightly to the upper part Of the shell.
The bands viii end In loops to which
viii be attached ropes from the balloon
bag.
The balloon bag itself Is q marvel Of
aeronautical engineering. It Is COM
posed Of $1,000 running feet Of rubber
lied fabric, ~ inches wide. or more
than seven and . third miles Of cloth
more than 81 feet wide. This vast
expanse Of fabric, more than three acres
in extent, was cut into 3.4s2 major
pieces, which were cemented together
with more than 800 gallons Of cement
to form the great bag. The work was
done in q huge room with sealed win
dows. AL air admitted to the room was
strained through canton flannel and the
workers, 80 in number, wore grit-free
"slumber shoes" of cloth.
Although the balloon room was 800
feet long and in places more than 100
feet wide, it was too small to spread out
the bag and the sections were gathered
in long wind-rows, or pleats, with only
the edges exposed for cementing. When
the fabric had been cemented, thou
sands of cubic feet of air were pumped
underneath to float" it of the floor for
inspection. Men under the cloth in
spected it foot by foot, looking through
it to strong light to find thin spots and
reinforce them with rubber patches.
Every foot of the huge expanse of cloth
in the balloon passed through rubber
izing machine 80 times each time re-
ceiving very thin coat of rubber.
The bag is surrounded by two wide
belts, or "catenary bands" to which are
attached the ropes for holding the bag
as gas is fed in for the fight and for
supporting the gondola. The lower
band, to which the gondola is to be
slung, is composed of heavy cloth, with
its lower edge cut into 100 carefully
designed scallops to spread the weight
to best advantage and to form attach
ments for the many ropes which will