An Investigation of Aircraft Heaters

By means of a hot-wire method, the thermal conductivity of air was measured from air temperatures of 50 degrees to 99 degrees F and the thermal conductivity of gasoline-engine exhauset gases were measured from gas temperatures of 250 degrees to 900 degrees F. The values obtained for air are in good agreement with other data that are available. The values of exhaust gases from an engine operating on fuel-air ratios between 0.056 to 0.085 are practically the same as those for air at the same temperature, but the richer mixtures (fuel-air ratios of 0.10 to 0.15) show increasingly larger values of thermal conductivity, the largest being approximately 30 percent greater than that of air. The thermal conductivity data obtained are shown in graphs at the end of this report.