2 aa IVY to determine the effects, principally thermal, of nuclear weapons on the structure of the B-47B. IVY .and CASTLE results were to be used either to support or modify existing theories relating to the thermal output of nuclear explosions to their effect on the B-47B. ELAINE TWO, code name of the B-47, was to be positioned on each shot so as to receive thermal inputs sufficient to raise the temperature of the critical skin panel to 370° F above ambient at 35,000 feet altitude, The skin panel considered critical was the 0.020 aluminum skin in the ailerons. The safety of crew and aircraft made it necessary to position ELAINE TWO according to the maximm probable yield, rather than the most probable yield of the device. This system resulted in relatively low thermal inputs on IVY, but on CASTLE the difference between maximum probable and most probable yield was generally smaller, resulting in higher thermal inputs. On BRAVO, Shot 1, the yield was higher than predicted and the aircraft received minor external damage, ‘ Calorimeters and radiometers for these projects were” supplied and maintained by the Naval Radiological Defense Laboratory. Statham pres- sure transducers of appropriate range and sensitivity were used to meagure blast inputs. Thermal effects were measured on 0.020, 0.040 and 0.188 aluminum and 0.040 magnesium, using both thermocouples and strain gauges or thermocouples alone. Instrumentation necessary to correlate the primary data and to accurately ascertain the spatial position and attitude of the aircraft was also provided. This instrumentation was ninety-three percent effective on the five shots in which ELAINE Two participated. AFWL/HO