OPERATIONS MANUAL
I. INTRODUCTION
A. Purpose of Manual
This manual is designed to serve as a guide in the prepar-
ation. launching. and tracking operations of constant-
level balloons. In the body of this manual, most of the
discussion applies specifically to the 20-foot diameter
balloon developed by General Mills, Inc. In Section IX,
a brief description is given of the other sizes of balloons
used for constant-level flight. The manual is based upon
the experiences and investigations of the Constant Level
Balloon Project, Research Division of the College of Engineer-
ing, New York University. The charta and tables which were
developed to use for this work are included in Appendix II
of the manual.
B. Principles of Altitude Control
For constant-level work, non-extensible balloons are used
for three reasons:
(l) With a given weight of equipment, it is possible to
determine before the release of the balloon, the
maximum altitude Which will be attained.
(2) Without special control equipment, it is possible
to maintain a nearly constant altitude for periods
from one to six hours, depending upon atmospheric
conditions and floating level. Generally, it is
not possible to extend such flights through a sun-
set.
(3) By adding altitude control equipment, it is possible
to maintain the balloon at various nearly constant,
predetermined levels for periods of much more than
six hours regardless of the time of day.
II. GENERAL MILLS 20-FOOT BALLOONS
A. Description
General Mills, Inc. of Minneapolis, Minnesota, has de-
veloped a series of non-extensible, plastic balloons.
These balloons are tear-drop in shape, made from extruded
polyethylene sheet, 0.001" thick. Cells are currently
produced.with a diameter of 7, 20, 30 and 70 feet. The
-7-