Figures 2 and 3 shaw the tear-drop cell ot the stressed tape
design developed by General Mills, Inc. The tilm is .001 inch polyethylene,
but_t-welded, with scotch tape laid along the seam to reinforce the seal and
to carry and distribute 1he load. These strips, which converge to the loaa
ring at the bottom, actually support the load.
The overloading ot a General Mills 20-tdot balloon on Flight 12 at
Lakehurst kept the lower end of the balloon open during ascent. The
ceiling was greatly reduced by the resulting dilution ot the helium with
air. On later flights an unsuccessful attempt to minimize this mixing
was made, using a 10-toot external appendix passing through the shroud
lines. This appendix fouled ir1 the rigging and twisted completely shut,
causing the balloon to burst at pressure-altitude. A moditicationwith
a 10-foot appendix outside the shroud lines also tailed in actual flight.
Figure 4 shows this appendix construction on a General M lls balloon which
is being inflated. The final style is shown in Figures 5 and 6. It con-
sists of a 2-foot external appendix stiffened with cardboard battens.
This is taped on the outside of the load ring. It serves as a one-way
valve which excludes air during ascent but allows the extra helium to
valve freely when the balloon is full. No external appendix can be used
Whenever the rate of rise exceeds 600 feet per minute. For optimum balloon
performance, it has been determined that: 1) the equipment load for the
General Mills 20-foot balloon should be held tinder 30 pounds; 2) ratEBot
rise should be less than 900 feet per minute; and 3) for maximlml altitudes
an external e ppendix is needed; hence 1he limiting rate of rise is about
600 feet per minute in this case.
Several experimental flights have been made using shrouded Dewey
and Almy neoprene balloons, as well as small and large experimental cells in
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