A proposed Walk-Around Sleeping Bag for inclusion in the F-111 and survival kits for other aircraft was evaluated in a cold chamber with temperatures below -40° F. Rectal temperature drops of 1° C were experienced with a mean heat debt of 57 kcal/m2 during six-hour exposures with human subjects. It was shown that insulation was insufficient and that larger men could not don this garment. Recommendations were made to drop consideration of this garment in favor of standard Air Force down-filled arctic survival equipment.
Ground temperature studies were initiated at Fairbanks, Alaska, to provide data for predicting temperatures of survival shelters warmed by radiation from the earth. Some of this data is presented here in the hope it may be interesting to investigators of mammalian microclimates. Holes to depths of 10 ft were instrumented with thermistors during September 1963 and readings were taken at regular intervals until July 1966. Insulated shelters were placed in the vicinity of instrumented holes and temperature data were obtained. Temperatures were also taken inside shelters occupied by human subjects. Instrumented shelters were placed on frozen Chena River and data obtained while unoccupied and during occupancy. Nearby thermistors were frozen to river ice under snow cover and with snow removed. Temperatures of ground surface beneath snow were -6° C when ambient air was -46° C. When ambient air was -40° C, temperatures inside shelters were as high as -8° C and when shelters were occupied temperatures were over +15° C. With ambient air below -40° C, temperature in unoccupied shelter on the river was -9° C, under snow -8° C, and where snow was removed -30° C.