Thermal insulation of materials with possible aerospace application.

Thermal insulation values for several materials that may have aerospace applications have been determined by a single method. Heat transfer across a specimen on a constant temperature heat source was measured by heat flow disc, and temperature on each side of the specimen was measured by thermistor. The data demonstrate that, with various thermal insulating materials, the primary factor in thermal insulation is the entrapped air. Where convective air currents were sufficiently reduced, insulative values for different materials varied only slightly. Reflective and nonreflective materials sandwiched into the insulators made little difference in these experiments, but if employed differently, might increase insulative values significantly.