roswell

D. Ballast Requirements
For a 20-foot General Mille balloon, a flow of ballast
of at least 200 grams per hour is needed to keep the bal-
loon aloft. Flow of the compass fluid used varies
(through a sharp-edged orifice) with the head, or vertical
distance between the tree surface of the liquid and the
orifice. It is not affected by the temperature or preuure,
so long as the reservoir is properly vented.
Flow also varies with the size and shape of tbe orifice.
Using round spinnerette orifices, the flow of various heads
has been computed and is shown in Table 3, Appendix II.
From a knowledge of the minimum head to be expected (de-
pending on the construction of the ballast reservoir and
its connection to the orifice), the desired rate of flow
can be obtained by proper selection of orifice size. While
200 grams per hour has been used successfully for the
usual floating altitudes of the General Mills 20-foot cells,
this figure should be considered as an abaolute minimum.
~ short period check of the flow rate through each ballaat
assembly prior to flight is recommended.
E. Altitude Sensitivity
The altitude gained by a balloon when its load is re-
duced by one kilogram is called its altitude sensitivity.
This amount is affected by the density of the atmosphere
at the floating levelJ for 20-foot balloons between
40,000 and 53,000 feet, it is roughly 1000 feet per kilo-
gram of weight lost. This weight is normally lost by
ballast dropping. The altitude sensitivity and the ballast
drop control the rate of rise of the ceiling. Graph 4,
Appendix II gives more exact values for this figure at
various altitudes.
F. Fo~s and Records
For the purpose of making standard pre-flight compu·tations,
a series of computation sheets have been draw• up. These
are shown in Appendix· I. Reward tags attached to component•
of the flight train have encouraged the finders to protect
the equipment and report its location for recovery. The
tags, questionnaires, and the warning notices which are
used on appropriate gear where squi-bs or acid are used are
shown in Figures 20 and 21.
V. BALLO<li INFLATION
A. Preparation of Balloon
From the moment the protective packing of the balloon is
removed, great care must be exercised to prevent tears
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