and wing accelerations, skin-temperature rise, and mal inputs were realize. then for the Ivy tests. elevator position. the case of Shot 1, where the yield was slightly greater than the maximum probable, good results were obtained. The aircraft sustained only minor The aircraft participated in every shot of the Castle series. The limiting condition on the aircraft was either 190 percent of the design limit allowable physica} damage, and the results indicated that sufficient information was recorded to meet the project bending moment on the horizontal stabilizer or 2 400 F temperature rise on the 0.020-inch magnesium skin on the elevators. In objectives. For Shots 1 through 5, the These data indicated that predictions of aircraft skin response to thermal inputs from highyield weapons were over-conservative. They also aircraft was positioned at time zero in a tail-to aspect for one of the two limiting conditions, whichever indicated the need for a hetter undurstanding of the was critical for the maximum predicted yield of the parameters involved in skin responses to thermal flux: e.g., convective and conductive cooling, as device concerned. For Shot 6, the aircraft was positioned ir a head~on aspect for conservative valucs of bending moments. Data obtained from a head-on well as the possible variance of absorption coefficients with change of incident angle of thermal inputs. orientation were the first experimental verification of theoretically predicted responses and. although conservative. were nevertheless extremely valuabic and necessary for a complete evaluation of aircraft Project 6.4 “Proof Testing of AW Ship Countermeasures” (WT-927), Bureau of Ships und Naval Radiological Defense Laboratory; G. G. Molumyhy, CAPT, USN, Project Officer. response to nuclear explosions. The maximum useful incremental peak temperature measured was 250 F rise on the 0.020-inch magnesium skin on the undersurface of the elevator during Shot 5. The theoretical overpressure criteria of washdown countermeasures on Ships and grounded level of 0.50 psi was attained safely on Shot 1, al~ though considerable sheet-metal damage resulted The maximum gust load ineasured was in incremental fectiveness of ships structures, (3) the tactical radiological recovery procedures on ships and grounded airerart, and (4) the extent of interior contamination The principal objectives were: aircraft, (2) the determination of the shielding ef- beading moment on the horizontal stabilizer of approximately 80 percent of Jesign limit load. and su:taniiity of ventilation protective devices aboard ship. The predicted responses of the critical skin areas to the Two remotely controlled ships, orc protected by a washdown countermeasure, were guided throush thermal) inputs received were conservative, but suf- ficient data werc obtained tc enable 4 more realistic empirical and theoretical determination of the delivery cupabilities of the B-36. regions of contaminated fallout. Special structuru configurations, Loiler ar ducts, ventilation test compartments, and aircraft werc installed on both chips to act as contaminant-collecting surfaces. Recoraing gamma~radiation detectors, uir ga.nplers, Project 6.2b ‘Thermal Effects on B-47B Aircralt in Flight’ (WT-926), Wright Air Development Center; C. L. Luchsinger, Project Officer Project 6.2b was a continuation of the experimen-~ tation begun on Ivy to determine the effects, princi- particle and differential faflout collectors, surface samples, and postshot radiation surveys were used to suppiy data cn the extent of contamination. These data showed that {i was possible for person- pally thermal, of nuclear detonations on a B-47 aircraft in flight. ,1) the evaluation The Castle results, when combined with previous data, will modify existing theories relating the B~47 response to thermal inputs. nel to receive lethal radiation dosage aboard un-~ protected ships and shipboard aircraft if used opera- tionally. Washdown effectiveness on ships and aircraft not in flight was eslimated to be 90 and 95 percent based on dosage and dose rute, respectively. Distance and shielding by the ships structures resulted in attenuation fractions ranging from 0.2 in The Ivy B-47B, with additional instrumentation, participated on all but Shot 5 of the Castle series. Recorded data included total thermal-input energies, intensities, and spectra as well ag overpressures, skin temperature response, and flight attitudes. The aircraft was flown and maintained by WADC personnel who were also responsible for instrumentation compartments close to weather surfaces to 0.001 in interior compartments below armored ducks, with respect to levels observed on weather decks. On unprotected ships and grounded aircraft, excessively long pemods of repetitious decontamination were and aircraft position determination. The average effectiveness of instrumentation for the series was 93 percent. required to achieve satistactory radiation levels: The aircraft was positioned on each shot to receive sufficient thermal energy to raise the temperature in the 0.020-inch skin on the ailerons to 370 [I above ambient. Assigned positions in space were computed on the basia of the maximum probable yield rather than the most probable. In most cases, higher ther- 114 when a washdown countermeasure had been in operation, very little effort wags needed to make the ship or aircraft sabitable. Very little contaminant entered either the boiler air system or ventilation systems For contaminating events of the type encountered in these tests, it appeared that: (1) washdown coun- termeasures will cnable ships and operational planes