Chapter 5 RESULTS The measurements and calculations are presented and discussed, shot by shot, in the succeeding paragraphs. Data are given concerning the diameter and heights to top and bottom of the cloud proper, as functions of time for a maximum of 10 minutes. Few data were obtained at later times and, with the exception noted in Chapter 6, are omitted in view of uncertainty as to motion of the cloud with the wind. . In general, the diameter data are considered the most accurate while the height to the top of the cloud is least reliable. This follows from the fact that the cloud towers high above the camera and the top cannot be seen. For the purposes of this report, the top of the cloud is measured at the top during the rise and near the edge after stabilization. Whenever a thunderhead (a small wisp of material going to higher altitudes than the cloud proper) is observed, the data are also given. The bottom.of the cloud is sometimes poorly defined, because of the massive stem, but roughly represents the cloud level about halfway from stem to edge. 5.1 SHOT 1 ’ Data from this detonation are less complete than from succecding shots. Two of the planes furnished adequate navigation data, and also usable films; fortunately, the worst camera failures occurred in the aircraft whose positions were unknown. Table 5.1 lists all of the films exposed for cloud Projects 9.1 and13.2, together with an evaluation of ‘their utility for these purposes. The results, given in Figure 5.1, are based on measurements from three aerial films (two from K—17C cameras and one from an Eclair) and are tied into the 13.2 data from ground-based cameras, which cover only the first 0.6 minute. The diameter curve is believed to be good to +3 percent for the first 5 minutes; after this the photographs are poor and only two measurements could be taken. The height-to-top figures are good to +3 percent for 4 minutes. Then they become increasingly uncertain; at 6 minutes the given data could be in error by +10 percent, and thereafter the prominent thunderhead provides the only reliable measurements. Height to bottom is probably goog to +5 per= cent out to 10 minutes. _Experience on this first shot led to corrective measures designed to improve the quality of the data on succeeding shats. 5.2 SHOT 2 Three of the aircraft furnished good navigation data (an estimated probable curve was derived for the fourth) and five of the eight films exposed are quite good. Table 5.2 lists’ all of the films exposed for Projects 9.1 and 13.2, together with evaluation as to their utility for cloud study. The results, given in Figure 5.2, are based on measurements from four K—17C and three Eclair films, and are tied into the 13.2 data from ground-based cameras. The diameter curve is felt to be good to +3 percent for 7 minutes, and only slightly poorer there20 SECRET TO eRLE RE 8 ee ehARID One Sa et ME om