spherical particle with a fall rate of 125 cm/sec is about 120 microns. Figure C.1 gives essen- tially no particles with fall rates as great as 125 cm/sec. However, Figure C.10 gives about 30 percentof the particles with diameters greater than 120 microns. This disagreement is possibly due to the effect of the micromerograph on weakly constructed Particles, and the effect may not be uniform onall types of particles. The above exampleillustrates the inconsistencies in the data and points out the need for caution in making interpretations based on them. 3.3 COMPARISON WITH RESULTS OF PREVIOUS TESTS Shots were fired during Operation Redwing under conditions similar to those of the Hardtack series, and some results are available from published reports, which may be used for com- parison purposes. Results on the ratios of Mo” to Kr®® and on the Sr® R-values as a function of altitude in the cloud for the first 4 hours are reproduced in Table 3.11 from Reference 29. It is noted that for the land and reef shots the Sr” R-values increase and the Mo" to Kr®® ratiog decrease in a manner generally comparable to the similar Hardtack events. On the water shots, the Sr R-values are nearly constant with altitude, as with Walnut, but the ratios of Mo*® tg Kr"® are not comparable. The faliout R-values for the Hardtack shots are generally not inconsistent with those arrived at for the Redwing shots by Project 2.63. The latter gave radionuclide compositions which generated computed decay curves in good agreement with those actually meagured on several different types of instruments. The R-values from Redwing are listed in Table 3.12. Fallout R-values for Sr® amd Cs'*" collected in different locations from Tewa and Zuni (land and reef shots) showed variations of up to an order of magnitude. The fallout collections from those stations closest to the zero point were most depleted in these nuclides. Flathead and Navajo (water surface shots) gave much less change in the R-values with distance from the zero point— at most a factor of 2. 3.4 EFFECTIVENESS OF INSTRUMENTATION The aircraftborne sampling equipment performed in a generally satisfactory manner throughout the entire operation with the exception of some malfunctioning of the gas compressor pumps after the first shot. This was due primarily to the shortage of time for checkout prior to actual operational use. As the participating personnel gained experience, communications improved and the sampling flights progressed more smoothly. Each of the three types of aircraft sampling equipment is considered to be well suited for its intended use. Difficulties experienced with the rocket samplers are fully described in Chapter 2 and Appendix A. 41