roswell

and pin holes from being made in the fabric. For example,
the film is so easily injured that it is not safe to lay
a folded-up balloon on a bare table-top or other hard
surface on which sander splinters might be found. For
this reason a clean ground cloth of canvas should always
be used for the lay-out of the balloon. Once the balloon
has been laid out on the ground cloth, it is made ready
for inflation and the rip line of the flight-termination
gear is inserwdinto the cell (see Sectioniii, C).
B. Use of Shot Bags and Releasing Device
While the balloon is being inflated it is necessary to
hold it in position. Under conditions of calm wind, thB
may be accomplished by simple fastening heavy weights to
the loading ring and allowing the entire balloon envelope
to rise freely above its anchor.
Since only 10 to 2Q% of the balloon is full at the surface
when the inflation is complete, it is possible to restrict
the volume filled and so cut down the area exposed to
the wind on days which are not calm. '!he volume required
can be expressed as the length of the bubble collected
at the head or top of the balloon. Having determined the
desired iength (see Section IV, B), the remainder of the
balloon may be held down on the ground cloth by weighted
bags wrapped in protective sheets of polyethylene (see
Fi.gures 22 and 23). Elliptical shot bags, weighing 100
pounds,are used to hold the base of the bubble to be tn-
flated. Twenty-pound sand bags are used to keep the
appendix closed to prevent filling of the balloon with air
and to restrict the uninflated folds or the balloon. A
more elaborate system of holding the gas in the upper section
of the bubble makes use of the General Mills releasing de-
vice shown in Figures 24 and 25. Motmted on 'Wheels, this
mechanism is rolled into position with the head of the
balloon lying across the platform. The protective roller
arms lock into position holding the bubble until launching.
This device is used with large loads when shot bags might
roll or slide off the balloon. As the arms open outward
as well as upward when the locking pins are removed, 1t is
necessary to position the platform with the arms opening
away from the bubble.
c. Inflation Techniques
When the balloon is manufactured, a polyethylene inflation
tube about 4" in diameter is inserted. This tube extends
from a few feet outside the appendix to near the top of
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