Flights 68 through 72: In July, 1948 this series of flights was made without ballast controls to determine the natural buoyancy of the General Mills, Inc. 20-foot .001" polyethylene balloons. Of five such flights, only two good barograph records were obtained, one daytime flight (70) and one night flight (71). In both cases a nearly constant level was maintained for about four hours at the highest altitude reached.
On the barogram of Flight 70 (Figure 25) a section of arrested descent may be noticed, preceded and followed by a nearly constant fall. The cause of this step is not apparent, although a check has been made of the atmospheric structure of that day.
[figure]
NYU BALLOON PROJECT FLIGHT 70
Showing 20' General Mills Balloon
Performance When No Ballast Was
Dropped
RELEASED AT HOLLOMAN AFB, N.M.—JULY 8, 1948
0633 MST — RECOVERED AT KENT, TEXAS
Figure 25
On Flight 71 marked oscillations are seen at the floating level and also during the descent portion of the barogram (Figure 26). Clearly these must represent atmospheric motions since no controls of any sort were in use. There is no reason to believe that rapid changes in superheat occurred, since the floating level was far above the cloud level. Also the flight was made at night and no sunshine was encountered.
[figure]
NYU BALLOON PROJECT FLIGHT 71
Barograph Record Of GM. 20 Ft. Plastic Balloon Showing
Balloon Performance When No Ballast Was Dropped.
RELEASED AT ALAMOGORDO N.M., 2042 MST—9 JULY, 1948
RECOVERED AT VALENTINE TEXAS, 10 JULY, 1948
ESTIMATED DURATION 10 HOURS
Figure 26
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