Shehtke flown a B-57 with J-65's, he stated that at a more recent test at the Mertin factory, an aircraft had taken off with a maximum gross weight and flown immediately to altitude. At 48,000 feet the pilot had encouni- ered difficulty with one of his engines and returned to the base. The indication was that a B-57 equipped with Avon engines would be as good as or better than a B57 equipped with J-65 engines. It was agreed at Edwards that the B-57 would be well-suited for the sampling mission and easily maintained in the Forvard Area in its then=present state of development, and that a request should be made to ARDC, by AFSWC, for early altitude testing of this aircraft. If the B=-57's were to be obtained for the early stages of CASTLE, the most likely source of procurement was from the eight to be assigned to Ed- verds for testing, BEST AVAILABLE COPY However, back at the Air Task Group Headquarters, General Estes had initiated a staff study of B-57 capabilities for CASTLE. By 16 October this study was completed and General Estes forwarded a memo to General Mills delineating reasons why the B-57 was no longer a logical CASTLE particdpant.” Test results from Martin indicated that the B-57 had de- veloped an eight-cycle buffet appearing at .72 Mach, which Martin engineers had been unable to locate. Martin had lost several eircraft through disintegration due to this flaw and was justly concerned over finding the cause. The Be57 still wallowed considerably at altitude. Its ceiling was 48,600 feet, according to the USAF Characteristics Chart, which was well below the anticipated and desired maximum. Severe engine difficulties had been experienced with the J-65 engine, insofer as production and operation were concerned, Therefore, only sixteen B-57's