On these flights fixed ballast leaks of from 250 to 600 grams per hour were used. These leaks were provided through round orifices rather than through needle valves which had been in use previously. This improvement reduced the possibility of clogging.
On Flight 43 the first model of an Olland-cycle pressure modulator was flown with a modified T-69 (400 mc) radiosonde transmitter. The results obtained on this flight were not satisfactory, but later test proved successful.
The train seen in Figure 16 is typical of those flown during this period. Note the presence of the device to rip the balloon when descending into air lanes and thus speed up its fall.
[figure]
Flight 16: Train, typical of those flown in April, 1948
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