Flight 29, with a manual ballast valve, was released just before sunset on 22 November. It was observed descending 50 miles north of Toronto, Ontario, Canada, 14 hours later. The average wind was 130 mph. Radio reception was for 69 minutes.
Of the other recent flights, satisfactory radio performance was enjoyed only on flight 36. Before any more flights are made, a better transmitter and battery pack will be needed. Even on this flight the signal was lost after 135 minutes, due to excessive range. The last plotted position was northeast of Tucumcari, N.M. This flight was recovered from Burlington, Iowa.
Time-height curves of this series are included in figures 53, 54 and 55. Despite the limited data, some results can be determined. For example, flight 32 is believed to have floated for at least 70 minutes within 1,000 feet of a constant level above 40,000 feet MSL.
Flight 35 also exhibited 32 minutes of constant-level flight before the radio signal was lost. From the remarkable distances that some of the others traveled (See flight summary Table VI, Appendix I) it is almost certain that they floated for long periods.
These flights included a simple-filter manual ballast valve assembly (Figure 9) designed to reduce equipment weight and cost. The performance of this equipment justifies its continued use for relatively short flights.
Considerable difficulty was experienced with the type of filter used. Experiments are now being conducted to improve the filter.
Because of limited data received from earlier flights, modified Fergusson meteorographs were added to the equipment train on flights 33, 35 and 39. As of January 1, 1948 none of these instruments have been recovered.
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