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Position of recording and radio instruments in the flight
train is in some oases dictated by the size and shape of
antennae or other special part. In general this type of
gear is not placed below the altitude control equipment
because of possibl~ damage which might result from
ballast being dropped upon them. ~pical trains are shown
in Figures 16, 17, and 18.
F. Flight Tools and Equipment
A list of tools and equipment and facilities which should
be provided for any launching site is given in Appendix II.
IV. PRE-FLIGHT COMPUTATIONS
A. Lifting Gas and Rate of Rise
When the equipment for a flight is in readiness and the
inflation procedure is to be begun, the total weight to
be lifted must be determined. A weight sheet (Shown in
Appendix I) is filled in, with the final weight of each
piece of gear with its rigging. In this work the wei~hts
of the equipment are measured in grams and kilograms. for
ease of computation. The gross load reported should be
accurate to the nearest 200 grams. The amount of lifting
gas to be used must be carefully figured to prevent in-
correct inflation which might result either in the bal-
loon failing to rise, or perhaps rising too fast and rup-
turing at its ceiling. After the total weight to be
lifted is found, a percentage of this total is added to
provide for lifting the load at some specified rate.
With a given excess of buoyancy, a balloon will lift its
load at an almost constant predictable speed. (The rate
of rise will increase by about 25% at higher altitudes,
due to the changes in balloon shape and decrease of air
density.) Graph 1 of Appendix II shows the relationship
between the free lift and the :t-ate of r·ise, with free
lift expressed as a percentage of the total or gross load
(which includes the weight of the balloon itself). For
example, if a gross load of 10.0 kilograms is to be lifted
at a desired ascent rate of 600 feet per minute, 9.2%
of the gross load should be added, giving a gross lift
of 10.0 t .920 • 10.920 kilograms. (The rete of rise
should not exceed 700 feet per minute if a standard appen-
dix is used.)
It should be noted that this graph, derived from equations
for spherical balloons, applies also to the tear-drop cells
of General .Mills, Inc., without regard for the balloon
die.mter.
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