(UCLA), were 400°F for the 0.020 in. magnesium skin of the B~36 aircraft and 350°F for the 0.025,in. aluminum skin of the B-47 aircraft. Gust loads were not to exceed 100 per cent limit load for any component. culation of tlast-induced loads was primarily the responsibility of Aliied Research Associates, Inc. (ARA). radiation were performed by UULA, Cal- Calculations relstive to thermal Utilizing the most conservative realistic values for all variables not firmly established, it was determined that the positioning of both aircraft for IVY would be based upon the maximum allowable skin temper- ature rise. For the lower yield weapon employed in Shot 9, UPSHOTKNOTHOLE, gust~loading was limiting. The exact position assigned each aircraft for the three shots is given in paragraph 2.4, Field Testing. 203 INSTRUMENTATION Since coth instrumented aircraft were manned, many of the problems related to data-recording were minimized. Remote control (external to the aircraft) of equipment and telemetering of the data were not neces~ sary. The equipment was located in a heated, pressurized compartment so thet teaperature and pressure extremes were not encountered. Aireraft vicration and shock acceleration in the air and also humidity, funei, ard salt spray on the ground were the main considerations governing recording equinment selection. The sensins elements, Leing located for the most part in regions that were neither heated nor pressurized, were subjected during each flicht to wide temperature and pressure fluctuations, as well as to the above mentior.ed adverse environmental conditions. In addition, certain sensing devices were subjected to thermal radiaticn, either directly or indirectly, The above factors were considered in the selection of in- strumertation, The major portion of the instrumentation was devoted to measuring and recordins aircraft responses including bending, shear, torsion, and acceleratior. measurements, To facilitate correlation of input and response, overpressure measurezents were also made, Jeneral fliczht data, such as airspeed, aitituize, and orientation with respect to the burst point, were setermirned ad recorded, Fhotocraphic instrumentation was emrloyei for visual resrons. ceterminstions. 2.3.1 Inruts ard Flirsht Data The measurement of overpressure=-inputs and the obtaining of general flisht data, such as airspeed inc alitituce, are discussed in the sno=pararrarhs followins. Standard aircraft equipment was used to determine the cesired flight variables, Existing ecuirment was modified in some instances to rrovide additional indicstors for use by project personnel operating the instrumentation ecsulpment. 2.3.1.1 Cverpressure Tao types of instrumentation were employed for meacuring overeprescure incats, (ne tyre, tne Sieh Frequency rressure “ecorder manuSacturea ov look Research Laooratories, used a plezoelectric crystal as « 49 -