A third method of holding the equipment at a nominal constant
altitude is to fly a cluster of standard meteorological balloons equipped
with ballast dropping devices and a device for releasing lifting balloons
should the cluster depart from the altitude limits desired. This method
is inherently unstable, as there are no proportioPAl restoring forces which
will act on the flabb,y, freely extensible meteorological balloons. The
success of this procedure depends on very careful balancing of the load
against the variable lift of the balloons.
This cluster method is of use and interest only as a stop-gap
method of lifting the Army equipment to altitude now, and has been the
method used while awaiting delivery of the non-extensible plastic balloons.
III d) e. A flight was made on 3 April 1947 using this method. A
cluster of 12 balloons meteorological carrying a radiosonde, a 15 lb.
d~ load and a series of ballast dropping devices was released from
the foo~ball field at Lehigh University, Bethlehem, Pa. The train was
to be towed to 30,000 ft. by' 2 lifting balloons which would then be
cut loose. The weight of the equipment was adjusted to equal the lift
of the balloons and presumably the train should have floated after the
towing balloons were cut off. Actually, due to lack of experience in
the difficulty of handling long balloon trains, auxiliary rigging lines
were needed to take up launching stresses. These lines fouled the main
flying line and the ballast which was to be dropped on parachutes. As a
result, the balloon train went to 50,000 ft. where the tow balloons worked
themselves free. The remaining train thereupon descended as fast as it
bad climbed (1,000 ft. per minute), landing in the ocean near Sandy Hook,
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