Flight 63: Released from Alamogordo, New Mexico, 1116 MST, May 13, 1948
Descended at Alamogordo, New Mexico
On this flight a Seyfang Laboratories balloon, made of neoprene-coated nylon, was flown with a valve in the appendix set to open after an internal pressure of 0.02 psi was built up. On an earlier flight (59) such a balloon was flown with no valve but an appendix held closed with a rubber band; it ruptured upon becoming full.
Both a constant ballast-flow orifice and an automatic ballast control were used to keep this balloon buoyant. In addition to the ballast, a surplus of buoyancy might have been acquired when superpressure was built up inside the cell. Despite these controls, the balloon began to descend after a short period of floating, and its descent was not checked (Figure 24).
[figure]
Figure 24
An analysis of the acceleration which could be gained from a loss of superheat indicated that if the coated fabric had absorbed radiation and gained 50°C over the outside air, the superheat thus obtained would be so great that its subsequent rapid loss (as by ventilation) could not be compensated for even with the ballast flowing at full rate. To improve the analysis of balloon flights, a measure of the temperature difference between lifting gas and air temperature was suggested.
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