coer 20 were expected to be off the assembly line by the end of 1953. Moreover, the limited range of the aircraft without bomb bay tanks made flight from the West Coast to Hawaii impossible. Range was limited also by excessive oil consumption and a small oil reservoir. Therefore, water- lift would be required to get the B-57 to the Proving Ground. Acces- sories for the aircraft were totally inadequate and mission-required modifications would be extremely difficult and costly. Flight and maintenance personnel for the aircraft were decidedly scarce. The Task Group 7.4 staff study clearly indicated that the B-57 had too many "bugs" to risk its use in CASTLE. Hed later tests proven the B~57 a better aircraft, the Air Task Group would have recommended the use of one on a limited basis during the latter stages of the operation. On this basis the decision was made to use featherweight B-36's for high altitude cloud sampling. B. SAMPLER CONTROL Originally scheduled for CASTLE participation was one B=36 effects aircraft, two B-36 featherweight controller-samplers, possibly a B-47 effects aircraft, and an RB-50 for photography. The question arose as to how to control the F-8, samplers should one B-36 fail to get air= borne, At Los Alamos on 13 August, General Estes, Colonel Kesling and Dr. Graves discussed the number of Be36's needed for the operation. LASL had written JIF SEVEN requesting an additional B-36 for control purposes, feeling that any substitute such as an RB-50 would be unsatis= factory. During Operation IVY this situation hed arisen. At that time the RB-50 was already considered marginal due to its inebility to attain aFWL/HO ae RRera CESSse