. =x. 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 decidedy scarce. The Task ty Group 7.4 staff study clearly indicated that the B-57 had too many "bugs" to risk its use in CASTLE. Had 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-84 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 B-36's needed for the operation. LASL had written JTF SEVEN requesting an additional B-36 for control purposes, feeling that any substitute such as an RB~50 would be unsatisfactory. During Operation IVY this situation had arisen. At that time the RB-50 was already considered marginal due to its inability to attain 2)